Print mtime before updating file metadata

If set to `no`, PFERD won't print status or report messages for not deleted files

.github/workflows/build-and-release.yml

@@ -0,0 +1,78 @@
+name: build-and-release
+
+on: push
+
+defaults:
+  run:
+    shell: bash
+
+jobs:
+
+  build:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, windows-latest, macos-latest]
+        python: ["3.9"]
+    steps:
+
+      - uses: actions/checkout@v3
+
+      - uses: actions/setup-python@v4
+        with:
+          python-version: ${{ matrix.python }}
+
+      - name: Set up project
+        if: matrix.os != 'windows-latest'
+        run: ./scripts/setup
+
+      - name: Set up project on windows
+        if: matrix.os == 'windows-latest'
+        # For some reason, `pip install --upgrade pip` doesn't work on
+        # 'windows-latest'. The installed pip version works fine however.
+        run: ./scripts/setup --no-pip
+
+      - name: Run checks
+        run: ./scripts/check
+
+      - name: Build
+        run: ./scripts/build
+
+      - name: Rename binary
+        # Glob in source location because on windows pyinstaller creates a file
+        # named "pferd.exe"
+        run: mv dist/pferd* dist/pferd-${{ matrix.os }}
+
+      - name: Upload binary
+        uses: actions/upload-artifact@v3
+        with:
+          name: Binaries
+          path: dist/pferd-${{ matrix.os }}
+
+  release:
+    runs-on: ubuntu-latest
+    if: startsWith(github.ref, 'refs/tags/v')
+    needs: build
+    steps:
+
+      - name: Download binaries
+        uses: actions/download-artifact@v3
+        with:
+          name: Binaries
+
+      - name: Rename binaries
+        run: |
+          mv pferd-ubuntu-latest pferd-linux
+          mv pferd-windows-latest pferd-windows.exe
+          mv pferd-macos-latest pferd-mac
+
+      - name: Create release
+        uses: softprops/action-gh-release@v1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          files: |
+            pferd-linux
+            pferd-windows.exe
+            pferd-mac

.github/workflows/package.yml

@@ -1,74 +0,0 @@
-name: Package Application with Pyinstaller
-
-on:
-  push:
-    branches:
-      - "*"
-    tags:
-      - "v*"
-
-jobs:
-  build:
-
-    runs-on: ${{ matrix.os }}
-    strategy:
-      matrix:
-        os: [ubuntu-latest, windows-latest, macos-latest]
-
-    steps:
-    - uses: actions/checkout@v2
-
-    - uses: actions/setup-python@v2
-      with:
-        python-version: '3.x'
-
-    - name: "Install dependencies"
-      run: "pip install setuptools keyring pyinstaller rich requests beautifulsoup4 -f --upgrade"
-
-    - name: "Install sync_url.py"
-      run: "pyinstaller sync_url.py -F"
-
-    - name: "Move artifact"
-      run: "mv dist/sync_url* dist/sync_url-${{ matrix.os }}"
-
-    - uses: actions/upload-artifact@v2
-      with:
-        name: "Pferd Sync URL"
-        path: "dist/sync_url*"
-
-  release:
-    name: Release
-
-    needs: [build]
-    runs-on: ubuntu-latest
-    if: startsWith(github.ref, 'refs/tags/')
-
-    env:
-      GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-
-    steps:
-    - name: "Checkout"
-      uses: actions/checkout@v2
-
-    - name: "Download artifacts"
-      uses: actions/download-artifact@v2
-      with:
-        name: "Pferd Sync URL"
-
-    - name: "look at folder structure"
-      run: "ls -lah"
-
-    - name: "Rename releases"
-      run: "mv sync_url-macos-latest pferd_sync_url_mac && mv sync_url-ubuntu-latest pferd_sync_url_linux && mv sync_url-windows-latest pferd_sync_url.exe"
-
-    - name: "Create release"
-      uses: softprops/action-gh-release@v1
-
-    - name: "Upload release artifacts"
-      uses: softprops/action-gh-release@v1
-      with:
-        body: "Download the correct sync_url for your platform and run it in the terminal or CMD. You might need to make it executable on Linux/Mac with `chmod +x <file>`. Also please enclose the *url you pass to the program in double quotes* or your shell might silently screw it up!"
-        files: |
-          pferd_sync_url_mac
-          pferd_sync_url_linux
-          pferd_sync_url.exe

.gitignore

@@ -1,15 +1,11 @@
-__pycache__/
-.venv/
-venv/
-.idea/
-build/
 .mypy_cache/
-.tmp/
-.env
-.vscode
-ilias_cookies.txt
-PFERD.egg-info/
+/.venv/
+/PFERD.egg-info/
+__pycache__/
+/.vscode/
+/.idea/
 
-# PyInstaller
-sync_url.spec
-dist/
+# pyinstaller
+/pferd.spec
+/build/
+/dist/

CHANGELOG.md

@@ -0,0 +1,208 @@
+# Changelog
+
+All notable changes to this project will be documented in this file. The format
+is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
+
+This project has its own custom versioning scheme. Version numbers consist of
+three parts (e. g. `3.1.5`).
+- The first number is increased on major rewrites or changes. What classifies as
+  a major change is up to the maintainers. This is pretty rare and a PFERD
+  version 4 should hopefully not be necessary.
+- The second number is increased on backwards-incompatible changes in behaviour.
+  This refers to any change that would make an existing setup behave differently
+  (e. g. renaming options or changing crawler behaviour). If this number is
+  increased, it may be necessary for you to adapt your own setup.
+- The third number is increased on backwards-compatible changes (e. g. adding
+  new options or commands, changing documentation, fixing bugs). Updates that
+  only increase this number should be safe and not require manual intervention.
+
+We will try to correctly classify changes as backwards-compatible or
+backwards-incompatible, but may occasionally make mistakes or stumble across
+ambiguous situations.
+
+## Unreleased
+
+## 3.5.0 - 2023-09-13
+
+### Added
+- `no-delete-prompt-override` conflict resolution strategy
+- Support for ILIAS learning modules
+- `show_not_deleted` option to stop printing the "Not Deleted" status or report
+  message. This combines nicely with the `no-delete-prompt-override` strategy,
+  causing PFERD to mostly ignore local-only files.
+- Support for mediacast video listings
+- Crawling of files in info tab
+
+### Changed
+- Remove size suffix for files in content pages
+
+### Fixed
+- Crawling of courses with the timeline view as the default tab
+- Crawling of file and custom opencast cards
+- Crawling of button cards without descriptions
+- Abort crawling when encountering an unexpected ilias root page redirect
+- Sanitize ascii control characters on Windows
+- Crawling of paginated past meetings
+- Ignore SCORM learning modules
+
+## 3.4.3 - 2022-11-29
+
+### Added
+- Missing documentation for `forums` option
+
+### Changed
+- Clear up error message shown when multiple paths are found to an element
+
+### Fixed
+- IPD crawler unnecessarily appending trailing slashes
+- Crawling opencast when ILIAS is set to English
+
+## 3.4.2 - 2022-10-26
+
+### Added
+- Recognize and crawl content pages in cards
+- Recognize and ignore surveys
+
+### Fixed
+- Forum crawling crashing when a thread has no messages at all
+- Forum crawling crashing when a forum has no threads at all
+- Ilias login failing in some cases
+- Crawling of paginated future meetings
+- IPD crawler handling of URLs without trailing slash
+
+## 3.4.1 - 2022-08-17
+
+### Added
+- Download of page descriptions
+- Forum download support
+- `pass` authenticator
+
+### Changed
+- Add `cpp` extension to default `link_regex` of IPD crawler
+- Mention hrefs in IPD crawler's `--explain` output for users of `link_regex` option
+- Simplify default IPD crawler `link_regex`
+
+### Fixed
+- IPD crawler crashes on some sites
+- Meeting name normalization for yesterday, today and tomorrow
+- Crawling of meeting file previews
+- Login with new login button html layout
+- Descriptions for courses are now placed in the correct subfolder when
+  downloading the whole desktop
+
+## 3.4.0 - 2022-05-01
+
+### Added
+- Message when Shibboleth entitlements need to be manually reviewed
+- Links to unofficial packages and repology in the readme
+
+### Changed
+- Increase minimum supported Python version to 3.9
+- Support video listings with more columns
+- Use UTF-8 when reading/writing the config file
+
+### Fixed
+- Crash during authentication when the Shibboleth session is still valid
+
+## 3.3.1 - 2022-01-15
+
+### Fixed
+- ILIAS login
+- Local video cache if `windows_paths` is enabled
+
+## 3.3.0 - 2022-01-09
+
+### Added
+- A KIT IPD crawler
+- Support for ILIAS cards
+- (Rudimentary) support for content pages
+- Support for multi-stream videos
+- Support for ILIAS 7
+
+### Removed
+- [Interpolation](https://docs.python.org/3/library/configparser.html#interpolation-of-values) in config file
+
+### Fixed
+- Crawling of recursive courses
+- Crawling files directly placed on the personal desktop
+- Ignore timestamps at the unix epoch as they crash on windows
+
+## 3.2.0 - 2021-08-04
+
+### Added
+- `--skip` command line option
+- Support for ILIAS booking objects
+
+### Changed
+- Using multiple path segments on left side of `-name->` now results in an
+  error. This was already forbidden by the documentation but silently accepted
+  by PFERD.
+- More consistent path printing in some `--explain` messages
+
+### Fixed
+- Nondeterministic name deduplication due to ILIAS reordering elements
+- More exceptions are handled properly
+
+## 3.1.0 - 2021-06-13
+
+If your config file doesn't do weird things with transforms, it should continue
+to work. If your `-re->` arrows behave weirdly, try replacing them with
+`-exact-re->` arrows. If you're on Windows, you might need to switch from `\`
+path separators to `/` in your regex rules.
+
+### Added
+- `skip` option for crawlers
+- Rules with `>>` instead of `>` as arrow head
+- `-exact-re->` arrow (behaves like `-re->` did previously)
+
+### Changed
+- The `-re->` arrow can now rename directories (like `-->`)
+- Use `/` instead of `\` as path separator for (regex) rules on Windows
+- Use the label to the left for exercises instead of the button name to
+  determine the folder name
+
+### Fixed
+- Video pagination handling in ILIAS crawler
+
+## 3.0.1 - 2021-06-01
+
+### Added
+- `credential-file` authenticator
+- `--credential-file` option for `kit-ilias-web` command
+- Warning if using concurrent tasks with `kit-ilias-web`
+
+### Changed
+- Cookies are now stored in a text-based format
+
+### Fixed
+- Date parsing now also works correctly in non-group exercises
+
+## 3.0.0 - 2021-05-31
+
+### Added
+- Proper config files
+- Concurrent crawling
+- Crawl external ILIAS links
+- Crawl uploaded exercise solutions
+- Explain what PFERD is doing and why (`--explain`)
+- More control over output (`--status`, `--report`)
+- Debug transform rules with `--debug-transforms`
+- Print report after exiting via Ctrl+C
+- Store crawler reports in `.report` JSON file
+- Extensive config file documentation (`CONFIG.md`)
+- Documentation for developers (`DEV.md`)
+- This changelog
+
+### Changed
+- Rewrote almost everything
+- Better error messages
+- Redesigned CLI
+- Redesigned transform rules
+- ILIAS crawling logic (paths may be different)
+- Better support for weird paths on Windows
+- Set user agent (`PFERD/<version>`)
+
+### Removed
+- Backwards compatibility with 2.x
+- Python files as config files
+- Some types of crawlers

CONFIG.md

@@ -0,0 +1,479 @@
+# Config file format
+
+A config file consists of sections. A section begins with a `[section]` header,
+which is followed by a list of `key = value` pairs. Comments must be on their
+own line and start with `#`. Multiline values must be indented beyond their key.
+Boolean values can be `yes` or `no`. For more details and some examples on the
+format, see the [configparser documentation][1] ([interpolation][2] is
+disabled).
+
+[1]: <https://docs.python.org/3/library/configparser.html#supported-ini-file-structure> "Supported INI File Structure"
+[2]: <https://docs.python.org/3/library/configparser.html#interpolation-of-values> "Interpolation of values"
+
+## The `DEFAULT` section
+
+This section contains global configuration values. It can also be used to set
+default values for the other sections.
+
+- `working_dir`: The directory PFERD operates in. Set to an absolute path to
+  make PFERD operate the same regardless of where it is executed from. All other
+  paths in the config file are interpreted relative to this path. If this path
+  is relative, it is interpreted relative to the script's working dir. `~` is
+  expanded to the current user's home directory. (Default: `.`)
+- `explain`: Whether PFERD should log and explain its actions and decisions in
+  detail. (Default: `no`)
+- `status`: Whether PFERD should print status updates (like `Crawled ...`,
+  `Added ...`) while running a crawler. (Default: `yes`)
+- `report`: Whether PFERD should print a report of added, changed and deleted
+   local files for all crawlers before exiting. (Default: `yes`)
+- `show_not_deleted`: Whether PFERD should print messages in status and report
+   when a local-only file wasn't deleted. Combines nicely with the
+   `no-delete-prompt-override` conflict resolution strategy.
+- `share_cookies`: Whether crawlers should share cookies where applicable. For
+  example, some crawlers share cookies if they crawl the same website using the
+  same account. (Default: `yes`)
+
+## The `crawl:*` sections
+
+Sections whose names start with `crawl:` are used to configure crawlers. The
+rest of the section name specifies the name of the crawler.
+
+A crawler synchronizes a remote resource to a local directory. There are
+different types of crawlers for different kinds of resources, e.g. ILIAS
+courses or lecture websites.
+
+Each crawl section represents an instance of a specific type of crawler. The
+`type` option is used to specify the crawler type. The crawler's name is usually
+used as the output directory. New crawlers can be created simply by adding a new
+crawl section to the config file.
+
+Depending on a crawler's type, it may have different options. For more details,
+see the type's [documentation](#crawler-types) below. The following options are
+common to all crawlers:
+
+- `type`: The available types are specified in [this section](#crawler-types).
+- `skip`: Whether the crawler should be skipped during normal execution. The
+  crawler can still be executed manually using the `--crawler` or `-C` flags.
+  (Default: `no`)
+- `output_dir`: The directory the crawler synchronizes files to. A crawler will
+  never place any files outside this directory. (Default: the crawler's name)
+- `redownload`: When to download a file that is already present locally.
+  (Default: `never-smart`)
+    - `never`: If a file is present locally, it is not downloaded again.
+    - `never-smart`: Like `never`, but PFERD tries to detect if an already
+      downloaded files has changed via some (unreliable) heuristics.
+    - `always`: All files are always downloaded, regardless of whether they are
+      already present locally.
+    - `always-smart`: Like `always`, but PFERD tries to avoid unnecessary
+      downloads via some (unreliable) heuristics.
+- `on_conflict`: What to do when the local and remote versions of a file or
+  directory differ, including when a file is replaced by a directory or a
+  directory by a file. (Default: `prompt`)
+    - `prompt`: Always ask the user before overwriting or deleting local files
+      and directories.
+    - `local-first`: Always keep the local file or directory. Equivalent to
+      using `prompt` and always choosing "no". Implies that `redownload` is set
+      to `never`.
+    - `remote-first`: Always keep the remote file or directory. Equivalent to
+      using `prompt` and always choosing "yes".
+    - `no-delete`: Never delete local files, but overwrite local files if the
+      remote file is different.
+    - `no-delete-prompt-overwrite`: Never delete local files, but prompt to
+      overwrite local files if the remote file is different. Combines nicely
+      with the `show_not_deleted` option.
+- `transform`: Rules for renaming and excluding certain files and directories.
+  For more details, see [this section](#transformation-rules). (Default: empty)
+- `tasks`: The maximum number of concurrent tasks (such as crawling or
+  downloading). (Default: `1`)
+- `downloads`: How many of those tasks can be download tasks at the same time.
+  Must not be greater than `tasks`. (Default: Same as `tasks`)
+- `task_delay`: Time (in seconds) that the crawler should wait between
+  subsequent tasks. Can be used as a sort of rate limit to avoid unnecessary
+  load for the crawl target. (Default: `0.0`)
+- `windows_paths`: Whether PFERD should find alternative names for paths that
+  are invalid on Windows. (Default: `yes` on Windows, `no` otherwise)
+
+Some crawlers may also require credentials for authentication. To configure how
+the crawler obtains its credentials, the `auth` option is used. It is set to the
+full name of an auth section (including the `auth:` prefix).
+
+Here is a simple example:
+
+```ini
+[auth:example]
+type = simple
+username = foo
+password = bar
+
+[crawl:something]
+type = some-complex-crawler
+auth = auth:example
+on_conflict = no-delete
+tasks = 3
+```
+
+## The `auth:*` sections
+
+Sections whose names start with `auth:` are used to configure authenticators. An
+authenticator provides a username and a password to one or more crawlers.
+
+Authenticators work similar to crawlers: A section represents an authenticator
+instance whose name is the rest of the section name. The type is specified by
+the `type` option.
+
+Depending on an authenticator's type, it may have different options. For more
+details, see the type's [documentation](#authenticator-types) below. The only
+option common to all authenticators is `type`:
+
+- `type`: The types are specified in [this section](#authenticator-types).
+
+## Crawler types
+
+### The `local` crawler
+
+This crawler crawls a local directory. It is really simple and mostly useful for
+testing different setups. The various delay options are meant to make the
+crawler simulate a slower, network-based crawler.
+
+- `target`: Path to the local directory to crawl. (Required)
+- `crawl_delay`: Artificial delay (in seconds) to simulate for crawl requests.
+  (Default: `0.0`)
+- `download_delay`: Artificial delay (in seconds) to simulate for download
+  requests. (Default: `0.0`)
+- `download_speed`: Download speed (in bytes per second) to simulate. (Optional)
+
+### The `kit-ipd` crawler
+
+This crawler crawls a KIT-IPD page by url. The root page can be crawled from
+outside the KIT network so you will be informed about any new/deleted files,
+but downloading files requires you to be within. Adding a show delay between
+requests is likely a good idea.
+
+- `target`: URL to a KIT-IPD page
+- `link_regex`: A regex that is matched against the `href` part of links. If it
+  matches, the given link is downloaded as a file. This is used to extract
+  files from KIT-IPD pages. (Default: `^.*?[^/]+\.(pdf|zip|c|cpp|java)$`)
+
+### The `kit-ilias-web` crawler
+
+This crawler crawls the KIT ILIAS instance.
+
+ILIAS is not great at handling too many concurrent requests. To avoid
+unnecessary load, please limit `tasks` to `1`.
+
+There is a spike in ILIAS usage at the beginning of lectures, so please don't
+run PFERD during those times.
+
+If you're automatically running PFERD periodically (e. g. via cron or a systemd
+timer), please randomize the start time or at least don't use the full hour. For
+systemd timers, this can be accomplished using the `RandomizedDelaySec` option.
+Also, please schedule the script to run in periods of low activity. Running the
+script once per day should be fine.
+
+- `target`: The ILIAS element to crawl. (Required)
+    - `desktop`: Crawl your personal desktop
+    - `<course id>`: Crawl the course with the given id
+    - `<url>`: Crawl a given element by URL (preferably the permanent URL linked
+      at the bottom of its ILIAS page)
+- `auth`: Name of auth section to use for login. (Required)
+- `tfa_auth`: Name of auth section to use for two-factor authentication. Only
+  uses the auth section's password. (Default: Anonymous `tfa` authenticator)
+- `links`: How to represent external links. (Default: `fancy`)
+    - `ignore`: Don't download links.
+    - `plaintext`: A text file containing only the URL.
+    - `fancy`: A HTML file looking like the ILIAS link element.
+    - `internet-shortcut`: An internet shortcut file (`.url` file).
+- `link_redirect_delay`: Time (in seconds) until `fancy` link files will
+  redirect to the actual URL. Set to a negative value to disable the automatic
+  redirect. (Default: `-1`)
+- `videos`: Whether to download videos. (Default: `no`)
+- `forums`: Whether to download forum threads. (Default: `no`)
+- `http_timeout`: The timeout (in seconds) for all HTTP requests. (Default:
+  `20.0`)
+
+## Authenticator types
+
+### The `simple` authenticator
+
+With this authenticator, the username and password can be set directly in the
+config file. If the username or password are not specified, the user is prompted
+via the terminal.
+
+- `username`: The username. (Optional)
+- `password`: The password. (Optional)
+
+### The `credential-file` authenticator
+
+This authenticator reads a username and a password from a credential file.
+
+- `path`: Path to the credential file. (Required)
+
+The credential file has exactly two lines (trailing newline optional). The first
+line starts with `username=` and contains the username, the second line starts
+with `password=` and contains the password. The username and password may
+contain any characters except a line break.
+
+```
+username=AzureDiamond
+password=hunter2
+```
+
+### The `keyring` authenticator
+
+This authenticator uses the system keyring to store passwords. The username can
+be set directly in the config file. If the username is not specified, the user
+is prompted via the terminal. If the keyring contains no entry or the entry is
+incorrect, the user is prompted for a password via the terminal and the password
+is stored in the keyring.
+
+- `username`: The username. (Optional)
+- `keyring_name`: The service name PFERD uses for storing credentials. (Default:
+  `PFERD`)
+
+### The `pass` authenticator
+
+This authenticator queries the [`pass` password manager][3] for a username and
+password. It tries to be mostly compatible with [browserpass][4] and
+[passff][5], so see those links for an overview of the format. If PFERD fails
+to load your password, you can use the `--explain` flag to see why.
+
+- `passname`: The name of the password to use (Required)
+- `username_prefixes`: A comma-separated list of username line prefixes
+  (Default: `login,username,user`)
+- `password_prefixes`: A comma-separated list of password line prefixes
+  (Default: `password,pass,secret`)
+
+[3]: <https://www.passwordstore.org/> "Pass: The Standard Unix Password Manager"
+[4]: <https://github.com/browserpass/browserpass-extension#organizing-password-store> "Organizing password store"
+[5]: <https://github.com/passff/passff#multi-line-format> "Multi-line format"
+
+### The `tfa` authenticator
+
+This authenticator prompts the user on the console for a two-factor
+authentication token. The token is provided as password and it is not cached.
+This authenticator does not support usernames.
+
+## Transformation rules
+
+Transformation rules are rules for renaming and excluding files and directories.
+They are specified line-by-line in a crawler's `transform` option. When a
+crawler needs to apply a rule to a path, it goes through this list top-to-bottom
+and applies the first matching rule.
+
+To see this process in action, you can use the `--debug-transforms` or flag or
+the `--explain` flag.
+
+Each rule has the format `SOURCE ARROW TARGET` (e. g. `foo/bar --> foo/baz`).
+The arrow specifies how the source and target are interpreted. The different
+kinds of arrows are documented below.
+
+`SOURCE` and `TARGET` are either a bunch of characters without spaces (e. g.
+`foo/bar`) or string literals (e. g, `"foo/b a r"`). The former syntax has no
+concept of escaping characters, so the backslash is just another character. The
+string literals however support Python's escape syntax (e. g.
+`"foo\\bar\tbaz"`). This also means that in string literals, backslashes must be
+escaped.
+
+`TARGET` can additionally be a single exclamation mark `!` (*not* `"!"`). When a
+rule with a `!` as target matches a path, the corresponding file or directory is
+ignored by the crawler instead of renamed.
+
+`TARGET` can also be omitted entirely. When a rule without target matches a
+path, the path is returned unmodified. This is useful to prevent rules further
+down from matching instead.
+
+Each arrow's behaviour can be modified slightly by changing the arrow's head
+from `>` to `>>`. When a rule with a `>>` arrow head matches a path, it doesn't
+return immediately like a normal arrow. Instead, it replaces the current path
+with its output and continues on to the next rule. In effect, this means that
+multiple rules can be applied sequentially.
+
+### The `-->` arrow
+
+The `-->` arrow is a basic renaming operation for files and directories. If a
+path matches `SOURCE`, it is renamed to `TARGET`.
+
+Example: `foo/bar --> baz`
+- Doesn't match `foo`, `a/foo/bar` or `foo/baz`
+- Converts `foo/bar` into `baz`
+- Converts `foo/bar/wargl` into `baz/wargl`
+
+Example: `foo/bar --> !`
+- Doesn't match `foo`, `a/foo/bar` or `foo/baz`
+- Ignores `foo/bar` and any of its children
+
+### The `-name->` arrow
+
+The `-name->` arrow lets you rename files and directories by their name,
+regardless of where they appear in the file tree. Because of this, its `SOURCE`
+must not contain multiple path segments, only a single name. This restriction
+does not apply to its `TARGET`.
+
+Example: `foo -name-> bar/baz`
+- Doesn't match `a/foobar/b` or `x/Foo/y/z`
+- Converts `hello/foo` into `hello/bar/baz`
+- Converts `foo/world` into `bar/baz/world`
+- Converts `a/foo/b/c/foo` into `a/bar/baz/b/c/bar/baz`
+
+Example: `foo -name-> !`
+- Doesn't match `a/foobar/b` or `x/Foo/y/z`
+- Ignores any path containing a segment `foo`
+
+### The `-exact->` arrow
+
+The `-exact->` arrow requires the path to match `SOURCE` exactly. The examples
+below show why this is useful.
+
+Example: `foo/bar -exact-> baz`
+- Doesn't match `foo`, `a/foo/bar` or `foo/baz`
+- Converts `foo/bar` into `baz`
+- Doesn't match `foo/bar/wargl`
+
+Example: `foo/bar -exact-> !`
+- Doesn't match `foo`, `a/foo/bar` or `foo/baz`
+- Ignores only `foo/bar`, not its children
+
+### The `-re->` arrow
+
+The `-re->` arrow is like the `-->` arrow but with regular expressions. `SOURCE`
+is a regular expression and `TARGET` an f-string based template. If a path
+matches `SOURCE`, the output path is created using `TARGET` as template.
+`SOURCE` is automatically anchored.
+
+`TARGET` uses Python's [format string syntax][6]. The *n*-th capturing group can
+be referred to as `{g<n>}` (e.g. `{g3}`). `{g0}` refers to the original path.
+If capturing group *n*'s contents are a valid integer, the integer value is
+available as `{i<n>}` (e.g. `{i3}`). If capturing group *n*'s contents are a
+valid float, the float value is available as `{f<n>}` (e.g. `{f3}`). If a
+capturing group is not present (e.g. when matching the string `cd` with the
+regex `(ab)?cd`), the corresponding variables are not defined.
+
+Python's format string syntax has rich options for formatting its arguments. For
+example, to left-pad the capturing group 3 with the digit `0` to width 5, you
+can use `{i3:05}`.
+
+PFERD even allows you to write entire expressions inside the curly braces, for
+example `{g2.lower()}` or `{g3.replace(' ', '_')}`.
+
+Example: `f(oo+)/be?ar -re-> B{g1.upper()}H/fear`
+- Doesn't match `a/foo/bar`, `foo/abc/bar`, `afoo/bar` or `foo/bars`
+- Converts `foo/bar` into `BOOH/fear`
+- Converts `fooooo/bear` into `BOOOOOH/fear`
+- Converts `foo/bar/baz` into `BOOH/fear/baz`
+
+[6]: <https://docs.python.org/3/library/string.html#format-string-syntax> "Format String Syntax"
+
+### The `-name-re->` arrow
+
+The `-name-re>` arrow is like a combination of the `-name->` and `-re->` arrows.
+
+Example: `(.*)\.jpeg -name-re-> {g1}.jpg`
+- Doesn't match `foo/bar.png`, `baz.JPEG` or `hello,jpeg`
+- Converts `foo/bar.jpeg` into `foo/bar.jpg`
+- Converts `foo.jpeg/bar/baz.jpeg` into `foo.jpg/bar/baz.jpg`
+
+Example: `\..+ -name-re-> !`
+- Doesn't match `.`, `test`, `a.b`
+- Ignores all files and directories starting with `.`.
+
+### The `-exact-re->` arrow
+
+The `-exact-re>` arrow is like a combination of the `-exact->` and `-re->`
+arrows.
+
+Example: `f(oo+)/be?ar -exactre-> B{g1.upper()}H/fear`
+- Doesn't match `a/foo/bar`, `foo/abc/bar`, `afoo/bar` or `foo/bars`
+- Converts `foo/bar` into `BOOH/fear`
+- Converts `fooooo/bear` into `BOOOOOH/fear`
+- Doesn't match `foo/bar/baz`
+
+### Example: Tutorials
+
+You have an ILIAS course with lots of tutorials, but are only interested in a
+single one.
+
+```
+tutorials/
+  |- tut_01/
+  |- tut_02/
+  |- tut_03/
+  ...
+```
+
+You can use a mix of normal and exact arrows to get rid of the other ones and
+move the `tutorials/tut_02/` folder to `my_tut/`:
+
+```
+tutorials/tut_02 --> my_tut
+tutorials -exact->
+tutorials --> !
+```
+
+The second rule is required for many crawlers since they use the rules to decide
+which directories to crawl. If it was missing when the crawler looks at
+`tutorials/`, the third rule would match. This means the crawler would not crawl
+the `tutorials/` directory and thus not discover that `tutorials/tut02/` exists.
+
+Since the second rule is only relevant for crawling, the `TARGET` is left out.
+
+### Example: Lecture slides
+
+You have a course with slides like `Lecture 3: Linear functions.PDF` and you
+would like to rename them to `03_linear_functions.pdf`.
+
+```
+Lectures/
+  |- Lecture 1: Introduction.PDF
+  |- Lecture 2: Vectors and matrices.PDF
+  |- Lecture 3: Linear functions.PDF
+  ...
+```
+
+To do this, you can use the most powerful of arrows: The regex arrow.
+
+```
+"Lectures/Lecture (\\d+): (.*)\\.PDF" -re-> "Lectures/{i1:02}_{g2.lower().replace(' ', '_')}.pdf"
+```
+
+Note the escaped backslashes on the `SOURCE` side.
+
+### Example: Crawl a Python project
+
+You are crawling a Python project and want to ignore all hidden files (files
+whose name starts with a `.`), all `__pycache__` directories and all markdown
+files (for some weird reason).
+
+```
+.gitignore
+.mypy_cache/
+.venv/
+CONFIG.md
+PFERD/
+  |- __init__.py
+  |- __main__.py
+  |- __pycache__/
+  |- authenticator.py
+  |- config.py
+  ...
+README.md
+...
+```
+
+For this task, the name arrows can be used.
+
+```
+\..*        -name-re-> !
+__pycache__ -name->    !
+.*\.md      -name-re-> !
+```
+
+### Example: Clean up names
+
+You want to convert all paths into lowercase and replace spaces with underscores
+before applying any rules. This can be achieved using the `>>` arrow heads.
+
+```
+(.*) -re->> "{g1.lower().replace(' ', '_')}"
+
+<other rules go here>
+```

DEV.md

@@ -0,0 +1,89 @@
+# PFERD Development Guide
+
+PFERD is packaged following the [Python Packaging User Guide][ppug] (in
+particular [this][ppug-1] and [this][ppug-2] guide).
+
+[ppug]: <https://packaging.python.org/> "Python Packaging User Guide"
+[ppug-1]: <https://packaging.python.org/tutorials/packaging-projects/> "Packaging Python Projects"
+[ppug-2]: <https://packaging.python.org/guides/distributing-packages-using-setuptools/> "Packaging and distributing projects"
+
+## Setting up a dev environment
+
+The use of [venv][venv] is recommended. To initially set up a development
+environment, run these commands in the same directory as this file:
+
+```
+$ python -m venv .venv
+$ . .venv/bin/activate
+$ ./scripts/setup
+```
+
+The setup script installs a few required dependencies and tools. It also
+installs PFERD via `pip install --editable .`, which means that you can just run
+`pferd` as if it was installed normally. Since PFERD was installed with
+`--editable`, there is no need to re-run `pip install` when the source code is
+changed.
+
+If you get any errors because pip can't update itself, try running
+`./scripts/setup --no-pip` instead of `./scripts/setup`.
+
+For more details, see [this part of the Python Tutorial][venv-tut] and
+[this section on "development mode"][ppug-dev].
+
+[venv]: <https://docs.python.org/3/library/venv.html> "venv - Creation of virtual environments"
+[venv-tut]: <https://docs.python.org/3/tutorial/venv.html> "12. Virtual Environments and Packages"
+[ppug-dev]: <https://packaging.python.org/guides/distributing-packages-using-setuptools/#working-in-development-mode> "Working in “development mode”"
+
+## Checking and formatting the code
+
+To run a set of checks against the code, run `./scripts/check` in the repo's
+root directory. This script will run a few tools installed by `./scripts/setup`
+against the entire project.
+
+To format the code, run `./scripts/format` in the repo's root directory.
+
+Before committing changes, please make sure the checks return no warnings and
+the code is formatted.
+
+## Contributing
+
+When submitting a PR that adds, changes or modifies a feature, please ensure
+that the corresponding documentation is updated as well. Also, please ensure
+that `./scripts/check` returns no warnings and the code has been run through
+`./scripts/format`.
+
+In your first PR, please add your name to the `LICENSE` file.
+
+## Releasing a new version
+
+This section describes the steps required to release a new version of PFERD.
+Usually, they don't need to performed manually and `scripts/bump-version` can be
+used instead.
+
+1. Update the version number in `PFERD/version.py`
+2. Update `CHANGELOG.md`
+3. Commit changes to `master` with message `Bump version to <version>` (e. g. `Bump version to 3.2.5`)
+4. Create annotated tag named `v<version>` (e. g. `v3.2.5`)
+    - Copy changes from changelog
+    - Remove `#` symbols (which git would interpret as comments)
+    - As the first line, add `Version <version> - <date>` (e. g. `Version 3.2.5 - 2021-05-24`)
+    - Leave the second line empty
+5. Fast-forward `latest` to `master`
+6. Push `master`, `latest` and the new tag
+
+Example tag annotation:
+```
+Version 3.2.5 - 2021-05-24
+
+Added
+- Support for concurrent downloads
+- Support for proper config files
+- This changelog
+
+Changed
+- Rewrote almost everything
+- Redesigned CLI
+
+Removed
+- Backwards compatibility with 2.x
+```

LICENSE

@@ -1,4 +1,6 @@
-Copyright 2019-2020 Garmelon, I-Al-Istannen, danstooamerican, pavelzw, TheChristophe, Scriptim
+Copyright 2019-2021 Garmelon, I-Al-Istannen, danstooamerican, pavelzw,
+                    TheChristophe, Scriptim, thelukasprobst, Toorero,
+                    Mr-Pine
 
 Permission is hereby granted, free of charge, to any person obtaining a copy of
 this software and associated documentation files (the "Software"), to deal in

PFERD/__init__.py

@@ -1,8 +0,0 @@
-# pylint: disable=invalid-name
-
-"""
-This module exports only what you need for a basic configuration. If you want a
-more complex configuration, you need to import the other submodules manually.
-"""
-
-from .pferd import Pferd

PFERD/__main__.py

@@ -0,0 +1,169 @@
+import argparse
+import asyncio
+import configparser
+import os
+import sys
+from pathlib import Path
+
+from .auth import AuthLoadError
+from .cli import PARSER, ParserLoadError, load_default_section
+from .config import Config, ConfigDumpError, ConfigLoadError, ConfigOptionError
+from .logging import log
+from .pferd import Pferd, PferdLoadError
+from .transformer import RuleParseError
+
+
+def load_config_parser(args: argparse.Namespace) -> configparser.ConfigParser:
+    log.explain_topic("Loading config")
+    parser = configparser.ConfigParser(interpolation=None)
+
+    if args.command is None:
+        log.explain("No CLI command specified, loading config from file")
+        Config.load_parser(parser, path=args.config)
+    else:
+        log.explain("CLI command specified, loading config from its arguments")
+        if args.command:
+            args.command(args, parser)
+
+    load_default_section(args, parser)
+
+    return parser
+
+
+def load_config(args: argparse.Namespace) -> Config:
+    try:
+        return Config(load_config_parser(args))
+    except ConfigLoadError as e:
+        log.error(str(e))
+        log.error_contd(e.reason)
+        sys.exit(1)
+    except ParserLoadError as e:
+        log.error(str(e))
+        sys.exit(1)
+
+
+def configure_logging_from_args(args: argparse.Namespace) -> None:
+    if args.explain is not None:
+        log.output_explain = args.explain
+    if args.status is not None:
+        log.output_status = args.status
+    if args.show_not_deleted is not None:
+        log.output_not_deleted = args.show_not_deleted
+    if args.report is not None:
+        log.output_report = args.report
+
+    # We want to prevent any unnecessary output if we're printing the config to
+    # stdout, otherwise it would not be a valid config file.
+    if args.dump_config_to == "-":
+        log.output_explain = False
+        log.output_status = False
+        log.output_report = False
+
+
+def configure_logging_from_config(args: argparse.Namespace, config: Config) -> None:
+    # In configure_logging_from_args(), all normal logging is already disabled
+    # whenever we dump the config. We don't want to override that decision with
+    # values from the config file.
+    if args.dump_config_to == "-":
+        return
+
+    try:
+        if args.explain is None:
+            log.output_explain = config.default_section.explain()
+        if args.status is None:
+            log.output_status = config.default_section.status()
+        if args.report is None:
+            log.output_report = config.default_section.report()
+        if args.show_not_deleted is None:
+            log.output_not_deleted = config.default_section.show_not_deleted()
+    except ConfigOptionError as e:
+        log.error(str(e))
+        sys.exit(1)
+
+
+def dump_config(args: argparse.Namespace, config: Config) -> None:
+    log.explain_topic("Dumping config")
+
+    if args.dump_config and args.dump_config_to is not None:
+        log.error("--dump-config and --dump-config-to can't be specified at the same time")
+        sys.exit(1)
+
+    try:
+        if args.dump_config:
+            config.dump()
+        elif args.dump_config_to == "-":
+            config.dump_to_stdout()
+        else:
+            config.dump(Path(args.dump_config_to))
+    except ConfigDumpError as e:
+        log.error(str(e))
+        log.error_contd(e.reason)
+        sys.exit(1)
+
+
+def main() -> None:
+    args = PARSER.parse_args()
+
+    # Configuring logging happens in two stages because CLI args have
+    # precedence over config file options and loading the config already
+    # produces some kinds of log messages (usually only explain()-s).
+    configure_logging_from_args(args)
+
+    config = load_config(args)
+
+    # Now, after loading the config file, we can apply its logging settings in
+    # all places that were not already covered by CLI args.
+    configure_logging_from_config(args, config)
+
+    if args.dump_config or args.dump_config_to is not None:
+        dump_config(args, config)
+        sys.exit()
+
+    try:
+        pferd = Pferd(config, args.crawler, args.skip)
+    except PferdLoadError as e:
+        log.unlock()
+        log.error(str(e))
+        sys.exit(1)
+
+    try:
+        if os.name == "nt":
+            # A "workaround" for the windows event loop somehow crashing after
+            # asyncio.run() completes. See:
+            # https://bugs.python.org/issue39232
+            # https://github.com/encode/httpx/issues/914#issuecomment-780023632
+            # TODO Fix this properly
+            loop = asyncio.get_event_loop()
+            loop.run_until_complete(pferd.run(args.debug_transforms))
+            loop.run_until_complete(asyncio.sleep(1))
+            loop.close()
+        else:
+            asyncio.run(pferd.run(args.debug_transforms))
+    except (ConfigOptionError, AuthLoadError) as e:
+        log.unlock()
+        log.error(str(e))
+        sys.exit(1)
+    except RuleParseError as e:
+        log.unlock()
+        e.pretty_print()
+        sys.exit(1)
+    except KeyboardInterrupt:
+        log.unlock()
+        log.explain_topic("Interrupted, exiting immediately")
+        log.explain("Open files and connections are left for the OS to clean up")
+        pferd.print_report()
+        # TODO Clean up tmp files
+        # And when those files *do* actually get cleaned up properly,
+        # reconsider if this should really exit with 1
+        sys.exit(1)
+    except Exception:
+        log.unlock()
+        log.unexpected_exception()
+        pferd.print_report()
+        sys.exit(1)
+    else:
+        pferd.print_report()
+
+
+if __name__ == "__main__":
+    main()

PFERD/auth/__init__.py

@@ -0,0 +1,29 @@
+from configparser import SectionProxy
+from typing import Callable, Dict
+
+from ..config import Config
+from .authenticator import Authenticator, AuthError, AuthLoadError, AuthSection  # noqa: F401
+from .credential_file import CredentialFileAuthenticator, CredentialFileAuthSection
+from .keyring import KeyringAuthenticator, KeyringAuthSection
+from .pass_ import PassAuthenticator, PassAuthSection
+from .simple import SimpleAuthenticator, SimpleAuthSection
+from .tfa import TfaAuthenticator
+
+AuthConstructor = Callable[[
+    str,                # Name (without the "auth:" prefix)
+    SectionProxy,       # Authenticator's section of global config
+    Config,             # Global config
+], Authenticator]
+
+AUTHENTICATORS: Dict[str, AuthConstructor] = {
+    "credential-file": lambda n, s, c:
+        CredentialFileAuthenticator(n, CredentialFileAuthSection(s), c),
+    "keyring": lambda n, s, c:
+        KeyringAuthenticator(n, KeyringAuthSection(s)),
+    "pass": lambda n, s, c:
+        PassAuthenticator(n, PassAuthSection(s)),
+    "simple": lambda n, s, c:
+        SimpleAuthenticator(n, SimpleAuthSection(s)),
+    "tfa": lambda n, s, c:
+        TfaAuthenticator(n),
+}

PFERD/auth/authenticator.py

@@ -0,0 +1,80 @@
+from abc import ABC, abstractmethod
+from typing import Tuple
+
+from ..config import Section
+
+
+class AuthLoadError(Exception):
+    pass
+
+
+class AuthError(Exception):
+    pass
+
+
+class AuthSection(Section):
+    def type(self) -> str:
+        value = self.s.get("type")
+        if value is None:
+            self.missing_value("type")
+        return value
+
+
+class Authenticator(ABC):
+    def __init__(self, name: str) -> None:
+        """
+        Initialize an authenticator from its name and its section in the config
+        file.
+
+        If you are writing your own constructor for your own authenticator,
+        make sure to call this constructor first (via super().__init__).
+
+        May throw an AuthLoadError.
+        """
+
+        self.name = name
+
+    @abstractmethod
+    async def credentials(self) -> Tuple[str, str]:
+        pass
+
+    async def username(self) -> str:
+        username, _ = await self.credentials()
+        return username
+
+    async def password(self) -> str:
+        _, password = await self.credentials()
+        return password
+
+    def invalidate_credentials(self) -> None:
+        """
+        Tell the authenticator that some or all of its credentials are invalid.
+
+        Authenticators should overwrite this function if they have a way to
+        deal with this issue that is likely to result in valid credentials
+        (e. g. prompting the user).
+        """
+
+        raise AuthError("Invalid credentials")
+
+    def invalidate_username(self) -> None:
+        """
+        Tell the authenticator that specifically its username is invalid.
+
+        Authenticators should overwrite this function if they have a way to
+        deal with this issue that is likely to result in valid credentials
+        (e. g. prompting the user).
+        """
+
+        raise AuthError("Invalid username")
+
+    def invalidate_password(self) -> None:
+        """
+        Tell the authenticator that specifically its password is invalid.
+
+        Authenticators should overwrite this function if they have a way to
+        deal with this issue that is likely to result in valid credentials
+        (e. g. prompting the user).
+        """
+
+        raise AuthError("Invalid password")

PFERD/auth/credential_file.py

@@ -0,0 +1,46 @@
+from pathlib import Path
+from typing import Tuple
+
+from ..config import Config
+from ..utils import fmt_real_path
+from .authenticator import Authenticator, AuthLoadError, AuthSection
+
+
+class CredentialFileAuthSection(AuthSection):
+    def path(self) -> Path:
+        value = self.s.get("path")
+        if value is None:
+            self.missing_value("path")
+        return Path(value)
+
+
+class CredentialFileAuthenticator(Authenticator):
+    def __init__(self, name: str, section: CredentialFileAuthSection, config: Config) -> None:
+        super().__init__(name)
+
+        path = config.default_section.working_dir() / section.path()
+        try:
+            with open(path, encoding="utf-8") as f:
+                lines = list(f)
+        except UnicodeDecodeError:
+            raise AuthLoadError(f"Credential file at {fmt_real_path(path)} is not encoded using UTF-8")
+        except OSError as e:
+            raise AuthLoadError(f"No credential file at {fmt_real_path(path)}") from e
+
+        if len(lines) != 2:
+            raise AuthLoadError("Credential file must be two lines long")
+        [uline, pline] = lines
+        uline = uline[:-1]  # Remove trailing newline
+        if pline.endswith("\n"):
+            pline = pline[:-1]
+
+        if not uline.startswith("username="):
+            raise AuthLoadError("First line must start with 'username='")
+        if not pline.startswith("password="):
+            raise AuthLoadError("Second line must start with 'password='")
+
+        self._username = uline[9:]
+        self._password = pline[9:]
+
+    async def credentials(self) -> Tuple[str, str]:
+        return self._username, self._password

PFERD/auth/keyring.py

@@ -0,0 +1,65 @@
+from typing import Optional, Tuple
+
+import keyring
+
+from ..logging import log
+from ..utils import agetpass, ainput
+from ..version import NAME
+from .authenticator import Authenticator, AuthError, AuthSection
+
+
+class KeyringAuthSection(AuthSection):
+    def username(self) -> Optional[str]:
+        return self.s.get("username")
+
+    def keyring_name(self) -> str:
+        return self.s.get("keyring_name", fallback=NAME)
+
+
+class KeyringAuthenticator(Authenticator):
+
+    def __init__(self, name: str, section: KeyringAuthSection) -> None:
+        super().__init__(name)
+
+        self._username = section.username()
+        self._password: Optional[str] = None
+        self._keyring_name = section.keyring_name()
+
+        self._password_invalidated = False
+        self._username_fixed = section.username() is not None
+
+    async def credentials(self) -> Tuple[str, str]:
+        # Request the username
+        if self._username is None:
+            async with log.exclusive_output():
+                self._username = await ainput("Username: ")
+
+        # First try looking it up in the keyring.
+        # Do not look it up if it was invalidated - we want to re-prompt in this case
+        if self._password is None and not self._password_invalidated:
+            self._password = keyring.get_password(self._keyring_name, self._username)
+
+        # If that fails it wasn't saved in the keyring - we need to
+        # read it from the user and store it
+        if self._password is None:
+            async with log.exclusive_output():
+                self._password = await agetpass("Password: ")
+                keyring.set_password(self._keyring_name, self._username, self._password)
+
+        self._password_invalidated = False
+        return self._username, self._password
+
+    def invalidate_credentials(self) -> None:
+        if not self._username_fixed:
+            self.invalidate_username()
+        self.invalidate_password()
+
+    def invalidate_username(self) -> None:
+        if self._username_fixed:
+            raise AuthError("Configured username is invalid")
+        else:
+            self._username = None
+
+    def invalidate_password(self) -> None:
+        self._password = None
+        self._password_invalidated = True

PFERD/auth/pass_.py

@@ -0,0 +1,98 @@
+import re
+import subprocess
+from typing import List, Tuple
+
+from ..logging import log
+from .authenticator import Authenticator, AuthError, AuthSection
+
+
+class PassAuthSection(AuthSection):
+    def passname(self) -> str:
+        if (value := self.s.get("passname")) is None:
+            self.missing_value("passname")
+        return value
+
+    def username_prefixes(self) -> List[str]:
+        value = self.s.get("username_prefixes", "login,username,user")
+        return [prefix.lower() for prefix in value.split(",")]
+
+    def password_prefixes(self) -> List[str]:
+        value = self.s.get("password_prefixes", "password,pass,secret")
+        return [prefix.lower() for prefix in value.split(",")]
+
+
+class PassAuthenticator(Authenticator):
+    PREFIXED_LINE_RE = r"([a-zA-Z]+):\s?(.*)"  # to be used with fullmatch
+
+    def __init__(self, name: str, section: PassAuthSection) -> None:
+        super().__init__(name)
+
+        self._passname = section.passname()
+        self._username_prefixes = section.username_prefixes()
+        self._password_prefixes = section.password_prefixes()
+
+    async def credentials(self) -> Tuple[str, str]:
+        log.explain_topic("Obtaining credentials from pass")
+
+        try:
+            log.explain(f"Calling 'pass show {self._passname}'")
+            result = subprocess.check_output(["pass", "show", self._passname], text=True)
+        except subprocess.CalledProcessError as e:
+            raise AuthError(f"Failed to get password info from {self._passname}: {e}")
+
+        prefixed = {}
+        unprefixed = []
+        for line in result.strip().splitlines():
+            if match := re.fullmatch(self.PREFIXED_LINE_RE, line):
+                prefix = match.group(1).lower()
+                value = match.group(2)
+                log.explain(f"Found prefixed line {line!r} with prefix {prefix!r}, value {value!r}")
+                if prefix in prefixed:
+                    raise AuthError(f"Prefix {prefix} specified multiple times")
+                prefixed[prefix] = value
+            else:
+                log.explain(f"Found unprefixed line {line!r}")
+                unprefixed.append(line)
+
+        username = None
+        for prefix in self._username_prefixes:
+            log.explain(f"Looking for username at prefix {prefix!r}")
+            if prefix in prefixed:
+                username = prefixed[prefix]
+                log.explain(f"Found username {username!r}")
+                break
+
+        password = None
+        for prefix in self._password_prefixes:
+            log.explain(f"Looking for password at prefix {prefix!r}")
+            if prefix in prefixed:
+                password = prefixed[prefix]
+                log.explain(f"Found password {password!r}")
+                break
+
+        if password is None and username is None:
+            log.explain("No username and password found so far")
+            log.explain("Using first unprefixed line as password")
+            log.explain("Using second unprefixed line as username")
+        elif password is None:
+            log.explain("No password found so far")
+            log.explain("Using first unprefixed line as password")
+        elif username is None:
+            log.explain("No username found so far")
+            log.explain("Using first unprefixed line as username")
+
+        if password is None:
+            if not unprefixed:
+                log.explain("Not enough unprefixed lines left")
+                raise AuthError("Password could not be determined")
+            password = unprefixed.pop(0)
+            log.explain(f"Found password {password!r}")
+
+        if username is None:
+            if not unprefixed:
+                log.explain("Not enough unprefixed lines left")
+                raise AuthError("Username could not be determined")
+            username = unprefixed.pop(0)
+            log.explain(f"Found username {username!r}")
+
+        return username, password

PFERD/auth/simple.py

@@ -0,0 +1,62 @@
+from typing import Optional, Tuple
+
+from ..logging import log
+from ..utils import agetpass, ainput
+from .authenticator import Authenticator, AuthError, AuthSection
+
+
+class SimpleAuthSection(AuthSection):
+    def username(self) -> Optional[str]:
+        return self.s.get("username")
+
+    def password(self) -> Optional[str]:
+        return self.s.get("password")
+
+
+class SimpleAuthenticator(Authenticator):
+    def __init__(self, name: str, section: SimpleAuthSection) -> None:
+        super().__init__(name)
+
+        self._username = section.username()
+        self._password = section.password()
+
+        self._username_fixed = self.username is not None
+        self._password_fixed = self.password is not None
+
+    async def credentials(self) -> Tuple[str, str]:
+        if self._username is not None and self._password is not None:
+            return self._username, self._password
+
+        async with log.exclusive_output():
+            if self._username is None:
+                self._username = await ainput("Username: ")
+            else:
+                print(f"Username: {self._username}")
+
+            if self._password is None:
+                self._password = await agetpass("Password: ")
+
+            # Intentionally returned inside the context manager so we know
+            # they're both not None
+            return self._username, self._password
+
+    def invalidate_credentials(self) -> None:
+        if self._username_fixed and self._password_fixed:
+            raise AuthError("Configured credentials are invalid")
+
+        if not self._username_fixed:
+            self._username = None
+        if not self._password_fixed:
+            self._password = None
+
+    def invalidate_username(self) -> None:
+        if self._username_fixed:
+            raise AuthError("Configured username is invalid")
+        else:
+            self._username = None
+
+    def invalidate_password(self) -> None:
+        if self._password_fixed:
+            raise AuthError("Configured password is invalid")
+        else:
+            self._password = None

PFERD/auth/tfa.py

@@ -0,0 +1,30 @@
+from typing import Tuple
+
+from ..logging import log
+from ..utils import ainput
+from .authenticator import Authenticator, AuthError
+
+
+class TfaAuthenticator(Authenticator):
+    def __init__(self, name: str) -> None:
+        super().__init__(name)
+
+    async def username(self) -> str:
+        raise AuthError("TFA authenticator does not support usernames")
+
+    async def password(self) -> str:
+        async with log.exclusive_output():
+            code = await ainput("TFA code: ")
+            return code
+
+    async def credentials(self) -> Tuple[str, str]:
+        raise AuthError("TFA authenticator does not support usernames")
+
+    def invalidate_username(self) -> None:
+        raise AuthError("TFA authenticator does not support usernames")
+
+    def invalidate_password(self) -> None:
+        pass
+
+    def invalidate_credentials(self) -> None:
+        pass

PFERD/authenticators.py

@@ -1,214 +0,0 @@
-"""
-General authenticators useful in many situations
-"""
-
-import getpass
-import logging
-from typing import Optional, Tuple
-
-from .logging import PrettyLogger
-
-LOGGER = logging.getLogger(__name__)
-PRETTY = PrettyLogger(LOGGER)
-
-try:
-    import keyring
-except ImportError:
-    pass
-
-
-class TfaAuthenticator:
-    # pylint: disable=too-few-public-methods
-    """
-    An authenticator for a TFA token. Always prompts the user, as the token can not be cached.
-    """
-
-    def __init__(self, reason: str):
-        """
-        Create a new tfa authenticator.
-
-        Arguments:
-            reason {str} -- the reason for obtaining the credentials
-        """
-        self._reason = reason
-
-    def get_token(self) -> str:
-        # pylint: disable=no-self-use
-        """
-        Prompts the user for the token and returns it.
-        """
-        print(f"Enter credentials ({self._reason})")
-        return getpass.getpass("TFA Token: ")
-
-
-class UserPassAuthenticator:
-    """
-    An authenticator for username-password combinations that prompts the user
-    for missing information.
-    """
-
-    def __init__(
-            self,
-            reason: str,
-            username: Optional[str] = None,
-            password: Optional[str] = None,
-    ) -> None:
-        """
-        reason   - what the credentials are used for
-        username - the username (if already known)
-        password - the password (if already known)
-        """
-
-        self._reason = reason
-
-        self._given_username = username
-        self._given_password = password
-
-        self._username = username
-        self._password = password
-
-    def get_credentials(self) -> Tuple[str, str]:
-        """
-        Returns a tuple (username, password). Prompts user for username or
-        password when necessary.
-        """
-
-        if self._username is None and self._given_username is not None:
-            self._username = self._given_username
-
-        if self._password is None and self._given_password is not None:
-            self._password = self._given_password
-
-        if self._username is None or self._password is None:
-            print(f"Enter credentials ({self._reason})")
-
-        username: str
-        if self._username is None:
-            username = input("Username: ")
-            self._username = username
-        else:
-            username = self._username
-
-        password: str
-        if self._password is None:
-            password = getpass.getpass(prompt="Password: ")
-            self._password = password
-        else:
-            password = self._password
-
-        return (username, password)
-
-    @property
-    def username(self) -> str:
-        """
-        The username. Accessing this property may cause the authenticator to
-        prompt the user.
-        """
-
-        (username, _) = self.get_credentials()
-        return username
-
-    @property
-    def password(self) -> str:
-        """
-        The password. Accessing this property may cause the authenticator to
-        prompt the user.
-        """
-
-        (_, password) = self.get_credentials()
-        return password
-
-    def invalidate_credentials(self) -> None:
-        """
-        Marks the credentials as invalid. If only a username was supplied in
-        the constructor, assumes that the username is valid and only the
-        password is invalid. If only a password was supplied in the
-        constructor, assumes that the password is valid and only the username
-        is invalid. Otherwise, assumes that username and password are both
-        invalid.
-        """
-
-        self._username = None
-        self._password = None
-
-        if self._given_username is not None and self._given_password is not None:
-            self._given_username = None
-            self._given_password = None
-
-
-class KeyringAuthenticator(UserPassAuthenticator):
-    """
-    An authenticator for username-password combinations that stores the
-    password using the system keyring service and prompts the user for missing
-    information.
-    """
-
-    def get_credentials(self) -> Tuple[str, str]:
-        """
-        Returns a tuple (username, password). Prompts user for username or
-        password when necessary.
-        """
-
-        if self._username is None and self._given_username is not None:
-            self._username = self._given_username
-
-        if self._password is None and self._given_password is not None:
-            self._password = self._given_password
-
-        if self._username is not None and self._password is None:
-            self._load_password()
-
-        if self._username is None or self._password is None:
-            print(f"Enter credentials ({self._reason})")
-
-        username: str
-        if self._username is None:
-            username = input("Username: ")
-            self._username = username
-        else:
-            username = self._username
-
-        if self._password is None:
-            self._load_password()
-
-        password: str
-        if self._password is None:
-            password = getpass.getpass(prompt="Password: ")
-            self._password = password
-            self._save_password()
-        else:
-            password = self._password
-
-        return (username, password)
-
-    def _load_password(self) -> None:
-        """
-        Loads the saved password associated with self._username from the system
-        keyring service (or None if not password has been saved yet) and stores
-        it in self._password.
-        """
-        self._password = keyring.get_password("pferd-ilias", self._username)
-
-    def _save_password(self) -> None:
-        """
-        Saves self._password to the system keyring service and associates it
-        with self._username.
-        """
-        keyring.set_password("pferd-ilias", self._username, self._password)
-
-    def invalidate_credentials(self) -> None:
-        """
-        Marks the credentials as invalid. If only a username was supplied in
-        the constructor, assumes that the username is valid and only the
-        password is invalid. If only a password was supplied in the
-        constructor, assumes that the password is valid and only the username
-        is invalid. Otherwise, assumes that username and password are both
-        invalid.
-        """
-
-        try:
-            keyring.delete_password("pferd-ilias", self._username)
-        except keyring.errors.PasswordDeleteError:
-            pass
-
-        super().invalidate_credentials()

PFERD/cli/__init__.py

@@ -0,0 +1,13 @@
+# isort: skip_file
+
+# The order of imports matters because each command module registers itself
+# with the parser from ".parser" and the import order affects the order in
+# which they appear in the help. Because of this, isort is disabled for this
+# file. Also, since we're reexporting or just using the side effect of
+# importing itself, we get a few linting warnings, which we're disabling as
+# well.
+
+from . import command_local  # noqa: F401 imported but unused
+from . import command_kit_ilias_web  # noqa: F401 imported but unused
+from . import command_kit_ipd  # noqa: F401 imported but unused
+from .parser import PARSER, ParserLoadError, load_default_section  # noqa: F401 imported but unused

PFERD/cli/command_kit_ilias_web.py

@@ -0,0 +1,120 @@
+import argparse
+import configparser
+from pathlib import Path
+
+from ..crawl.ilias.file_templates import Links
+from ..logging import log
+from .parser import (CRAWLER_PARSER, SUBPARSERS, BooleanOptionalAction, ParserLoadError, load_crawler,
+                     show_value_error)
+
+SUBPARSER = SUBPARSERS.add_parser(
+    "kit-ilias-web",
+    parents=[CRAWLER_PARSER],
+)
+
+GROUP = SUBPARSER.add_argument_group(
+    title="kit-ilias-web crawler arguments",
+    description="arguments for the 'kit-ilias-web' crawler",
+)
+GROUP.add_argument(
+    "target",
+    type=str,
+    metavar="TARGET",
+    help="course id, 'desktop', or ILIAS URL to crawl"
+)
+GROUP.add_argument(
+    "output",
+    type=Path,
+    metavar="OUTPUT",
+    help="output directory"
+)
+GROUP.add_argument(
+    "--username", "-u",
+    type=str,
+    metavar="USERNAME",
+    help="user name for authentication"
+)
+GROUP.add_argument(
+    "--keyring",
+    action=BooleanOptionalAction,
+    help="use the system keyring to store and retrieve passwords"
+)
+GROUP.add_argument(
+    "--credential-file",
+    type=Path,
+    metavar="PATH",
+    help="read username and password from a credential file"
+)
+GROUP.add_argument(
+    "--links",
+    type=show_value_error(Links.from_string),
+    metavar="OPTION",
+    help="how to represent external links"
+)
+GROUP.add_argument(
+    "--link-redirect-delay",
+    type=int,
+    metavar="SECONDS",
+    help="time before 'fancy' links redirect to to their target (-1 to disable)"
+)
+GROUP.add_argument(
+    "--videos",
+    action=BooleanOptionalAction,
+    help="crawl and download videos"
+)
+GROUP.add_argument(
+    "--forums",
+    action=BooleanOptionalAction,
+    help="crawl and download forum posts"
+)
+GROUP.add_argument(
+    "--http-timeout", "-t",
+    type=float,
+    metavar="SECONDS",
+    help="timeout for all HTTP requests"
+)
+
+
+def load(
+        args: argparse.Namespace,
+        parser: configparser.ConfigParser,
+) -> None:
+    log.explain("Creating config for command 'kit-ilias-web'")
+
+    parser["crawl:ilias"] = {}
+    section = parser["crawl:ilias"]
+    load_crawler(args, section)
+
+    section["type"] = "kit-ilias-web"
+    section["target"] = str(args.target)
+    section["output_dir"] = str(args.output)
+    section["auth"] = "auth:ilias"
+    if args.links is not None:
+        section["links"] = str(args.links.value)
+    if args.link_redirect_delay is not None:
+        section["link_redirect_delay"] = str(args.link_redirect_delay)
+    if args.videos is not None:
+        section["videos"] = "yes" if args.videos else "no"
+    if args.forums is not None:
+        section["forums"] = "yes" if args.forums else "no"
+    if args.http_timeout is not None:
+        section["http_timeout"] = str(args.http_timeout)
+
+    parser["auth:ilias"] = {}
+    auth_section = parser["auth:ilias"]
+    if args.credential_file is not None:
+        if args.username is not None:
+            raise ParserLoadError("--credential-file and --username can't be used together")
+        if args.keyring:
+            raise ParserLoadError("--credential-file and --keyring can't be used together")
+        auth_section["type"] = "credential-file"
+        auth_section["path"] = str(args.credential_file)
+    elif args.keyring:
+        auth_section["type"] = "keyring"
+    else:
+        auth_section["type"] = "simple"
+    if args.username is not None:
+        auth_section["username"] = args.username
+
+
+SUBPARSER.set_defaults(command=load)

PFERD/cli/command_kit_ipd.py

@@ -0,0 +1,54 @@
+import argparse
+import configparser
+from pathlib import Path
+
+from ..logging import log
+from .parser import CRAWLER_PARSER, SUBPARSERS, load_crawler
+
+SUBPARSER = SUBPARSERS.add_parser(
+    "kit-ipd",
+    parents=[CRAWLER_PARSER],
+)
+
+GROUP = SUBPARSER.add_argument_group(
+    title="kit ipd crawler arguments",
+    description="arguments for the 'kit-ipd' crawler",
+)
+GROUP.add_argument(
+    "--link-regex",
+    type=str,
+    metavar="REGEX",
+    help="href-matching regex to identify downloadable files"
+)
+GROUP.add_argument(
+    "target",
+    type=str,
+    metavar="TARGET",
+    help="url to crawl"
+)
+GROUP.add_argument(
+    "output",
+    type=Path,
+    metavar="OUTPUT",
+    help="output directory"
+)
+
+
+def load(
+        args: argparse.Namespace,
+        parser: configparser.ConfigParser,
+) -> None:
+    log.explain("Creating config for command 'kit-ipd'")
+
+    parser["crawl:kit-ipd"] = {}
+    section = parser["crawl:kit-ipd"]
+    load_crawler(args, section)
+
+    section["type"] = "kit-ipd"
+    section["target"] = str(args.target)
+    section["output_dir"] = str(args.output)
+    if args.link_regex:
+        section["link_regex"] = str(args.link_regex)
+
+
+SUBPARSER.set_defaults(command=load)

PFERD/cli/command_local.py

@@ -0,0 +1,70 @@
+import argparse
+import configparser
+from pathlib import Path
+
+from ..logging import log
+from .parser import CRAWLER_PARSER, SUBPARSERS, load_crawler
+
+SUBPARSER = SUBPARSERS.add_parser(
+    "local",
+    parents=[CRAWLER_PARSER],
+)
+
+GROUP = SUBPARSER.add_argument_group(
+    title="local crawler arguments",
+    description="arguments for the 'local' crawler",
+)
+GROUP.add_argument(
+    "target",
+    type=Path,
+    metavar="TARGET",
+    help="directory to crawl"
+)
+GROUP.add_argument(
+    "output",
+    type=Path,
+    metavar="OUTPUT",
+    help="output directory"
+)
+GROUP.add_argument(
+    "--crawl-delay",
+    type=float,
+    metavar="SECONDS",
+    help="artificial delay to simulate for crawl requests"
+)
+GROUP.add_argument(
+    "--download-delay",
+    type=float,
+    metavar="SECONDS",
+    help="artificial delay to simulate for download requests"
+)
+GROUP.add_argument(
+    "--download-speed",
+    type=int,
+    metavar="BYTES_PER_SECOND",
+    help="download speed to simulate"
+)
+
+
+def load(
+        args: argparse.Namespace,
+        parser: configparser.ConfigParser,
+) -> None:
+    log.explain("Creating config for command 'local'")
+
+    parser["crawl:local"] = {}
+    section = parser["crawl:local"]
+    load_crawler(args, section)
+
+    section["type"] = "local"
+    section["target"] = str(args.target)
+    section["output_dir"] = str(args.output)
+    if args.crawl_delay is not None:
+        section["crawl_delay"] = str(args.crawl_delay)
+    if args.download_delay is not None:
+        section["download_delay"] = str(args.download_delay)
+    if args.download_speed is not None:
+        section["download_speed"] = str(args.download_speed)
+
+
+SUBPARSER.set_defaults(command=load)

PFERD/cli/parser.py

@@ -0,0 +1,245 @@
+import argparse
+import configparser
+from argparse import ArgumentTypeError
+from pathlib import Path
+from typing import Any, Callable, List, Optional, Sequence, Union
+
+from ..output_dir import OnConflict, Redownload
+from ..version import NAME, VERSION
+
+
+class ParserLoadError(Exception):
+    pass
+
+
+# TODO Replace with argparse version when updating to 3.9?
+class BooleanOptionalAction(argparse.Action):
+    def __init__(
+            self,
+            option_strings: List[str],
+            dest: Any,
+            default: Any = None,
+            type: Any = None,
+            choices: Any = None,
+            required: Any = False,
+            help: Any = None,
+            metavar: Any = None,
+    ):
+        if len(option_strings) != 1:
+            raise ValueError("There must be exactly one option string")
+        [self.name] = option_strings
+        if not self.name.startswith("--"):
+            raise ValueError(f"{self.name!r} doesn't start with '--'")
+        if self.name.startswith("--no-"):
+            raise ValueError(f"{self.name!r} starts with '--no-'")
+
+        options = [self.name, "--no-" + self.name[2:]]
+
+        super().__init__(
+            options,
+            dest,
+            nargs=0,
+            default=default,
+            type=type,
+            choices=choices,
+            required=required,
+            help=help,
+            metavar=metavar,
+        )
+
+    def __call__(
+            self,
+            parser: argparse.ArgumentParser,
+            namespace: argparse.Namespace,
+            values: Union[str, Sequence[Any], None],
+            option_string: Optional[str] = None,
+    ) -> None:
+        if option_string and option_string in self.option_strings:
+            value = not option_string.startswith("--no-")
+            setattr(namespace, self.dest, value)
+
+    def format_usage(self) -> str:
+        return "--[no-]" + self.name[2:]
+
+
+def show_value_error(inner: Callable[[str], Any]) -> Callable[[str], Any]:
+    """
+    Some validation functions (like the from_string in our enums) raise a ValueError.
+    Argparse only pretty-prints ArgumentTypeErrors though, so we need to wrap our ValueErrors.
+    """
+    def wrapper(input: str) -> Any:
+        try:
+            return inner(input)
+        except ValueError as e:
+            raise ArgumentTypeError(e)
+    return wrapper
+
+
+CRAWLER_PARSER = argparse.ArgumentParser(add_help=False)
+CRAWLER_PARSER_GROUP = CRAWLER_PARSER.add_argument_group(
+    title="general crawler arguments",
+    description="arguments common to all crawlers",
+)
+CRAWLER_PARSER_GROUP.add_argument(
+    "--redownload", "-r",
+    type=show_value_error(Redownload.from_string),
+    metavar="OPTION",
+    help="when to download a file that's already present locally"
+)
+CRAWLER_PARSER_GROUP.add_argument(
+    "--on-conflict",
+    type=show_value_error(OnConflict.from_string),
+    metavar="OPTION",
+    help="what to do when local and remote files or directories differ"
+)
+CRAWLER_PARSER_GROUP.add_argument(
+    "--transform", "-T",
+    action="append",
+    type=str,
+    metavar="RULE",
+    help="add a single transformation rule. Can be specified multiple times"
+)
+CRAWLER_PARSER_GROUP.add_argument(
+    "--tasks", "-n",
+    type=int,
+    metavar="N",
+    help="maximum number of concurrent tasks (crawling, downloading)"
+)
+CRAWLER_PARSER_GROUP.add_argument(
+    "--downloads", "-N",
+    type=int,
+    metavar="N",
+    help="maximum number of tasks that may download data at the same time"
+)
+CRAWLER_PARSER_GROUP.add_argument(
+    "--task-delay", "-d",
+    type=float,
+    metavar="SECONDS",
+    help="time the crawler should wait between subsequent tasks"
+)
+CRAWLER_PARSER_GROUP.add_argument(
+    "--windows-paths",
+    action=BooleanOptionalAction,
+    help="whether to repair invalid paths on windows"
+)
+
+
+def load_crawler(
+        args: argparse.Namespace,
+        section: configparser.SectionProxy,
+) -> None:
+    if args.redownload is not None:
+        section["redownload"] = args.redownload.value
+    if args.on_conflict is not None:
+        section["on_conflict"] = args.on_conflict.value
+    if args.transform is not None:
+        section["transform"] = "\n" + "\n".join(args.transform)
+    if args.tasks is not None:
+        section["tasks"] = str(args.tasks)
+    if args.downloads is not None:
+        section["downloads"] = str(args.downloads)
+    if args.task_delay is not None:
+        section["task_delay"] = str(args.task_delay)
+    if args.windows_paths is not None:
+        section["windows_paths"] = "yes" if args.windows_paths else "no"
+
+
+PARSER = argparse.ArgumentParser()
+PARSER.set_defaults(command=None)
+PARSER.add_argument(
+    "--version",
+    action="version",
+    version=f"{NAME} {VERSION} (https://github.com/Garmelon/PFERD)",
+)
+PARSER.add_argument(
+    "--config", "-c",
+    type=Path,
+    metavar="PATH",
+    help="custom config file"
+)
+PARSER.add_argument(
+    "--dump-config",
+    action="store_true",
+    help="dump current configuration to the default config path and exit"
+)
+PARSER.add_argument(
+    "--dump-config-to",
+    metavar="PATH",
+    help="dump current configuration to a file and exit."
+    " Use '-' as path to print to stdout instead"
+)
+PARSER.add_argument(
+    "--debug-transforms",
+    action="store_true",
+    help="apply transform rules to files of previous run"
+)
+PARSER.add_argument(
+    "--crawler", "-C",
+    action="append",
+    type=str,
+    metavar="NAME",
+    help="only execute a single crawler."
+    " Can be specified multiple times to execute multiple crawlers"
+)
+PARSER.add_argument(
+    "--skip", "-S",
+    action="append",
+    type=str,
+    metavar="NAME",
+    help="don't execute this particular crawler."
+    " Can be specified multiple times to skip multiple crawlers"
+)
+PARSER.add_argument(
+    "--working-dir",
+    type=Path,
+    metavar="PATH",
+    help="custom working directory"
+)
+PARSER.add_argument(
+    "--explain",
+    action=BooleanOptionalAction,
+    help="log and explain in detail what PFERD is doing"
+)
+PARSER.add_argument(
+    "--status",
+    action=BooleanOptionalAction,
+    help="print status updates while PFERD is crawling"
+)
+PARSER.add_argument(
+    "--report",
+    action=BooleanOptionalAction,
+    help="print a report of all local changes before exiting"
+)
+PARSER.add_argument(
+    "--share-cookies",
+    action=BooleanOptionalAction,
+    help="whether crawlers should share cookies where applicable"
+)
+PARSER.add_argument(
+    "--show-not-deleted",
+    action=BooleanOptionalAction,
+    help="print messages in status and report when PFERD did not delete a local only file"
+)
+
+
+def load_default_section(
+        args: argparse.Namespace,
+        parser: configparser.ConfigParser,
+) -> None:
+    section = parser[parser.default_section]
+
+    if args.working_dir is not None:
+        section["working_dir"] = str(args.working_dir)
+    if args.explain is not None:
+        section["explain"] = "yes" if args.explain else "no"
+    if args.status is not None:
+        section["status"] = "yes" if args.status else "no"
+    if args.report is not None:
+        section["report"] = "yes" if args.report else "no"
+    if args.share_cookies is not None:
+        section["share_cookies"] = "yes" if args.share_cookies else "no"
+    if args.show_not_deleted is not None:
+        section["show_not_deleted"] = "yes" if args.show_not_deleted else "no"
+
+
+SUBPARSERS = PARSER.add_subparsers(title="crawlers")

PFERD/config.py

@@ -0,0 +1,193 @@
+import asyncio
+import os
+import sys
+from configparser import ConfigParser, SectionProxy
+from pathlib import Path
+from typing import Any, List, NoReturn, Optional, Tuple
+
+from rich.markup import escape
+
+from .logging import log
+from .utils import fmt_real_path, prompt_yes_no
+
+
+class ConfigLoadError(Exception):
+    """
+    Something went wrong while loading the config from a file.
+    """
+
+    def __init__(self, path: Path, reason: str):
+        super().__init__(f"Failed to load config from {fmt_real_path(path)}")
+        self.path = path
+        self.reason = reason
+
+
+class ConfigOptionError(Exception):
+    """
+    An option in the config file has an invalid or missing value.
+    """
+
+    def __init__(self, section: str, key: str, desc: str):
+        super().__init__(f"Section {section!r}, key {key!r}: {desc}")
+        self.section = section
+        self.key = key
+        self.desc = desc
+
+
+class ConfigDumpError(Exception):
+    def __init__(self, path: Path, reason: str):
+        super().__init__(f"Failed to dump config to {fmt_real_path(path)}")
+        self.path = path
+        self.reason = reason
+
+
+class Section:
+    """
+    Base class for the crawler and auth section classes.
+    """
+
+    def __init__(self, section: SectionProxy):
+        self.s = section
+
+    def error(self, key: str, desc: str) -> NoReturn:
+        raise ConfigOptionError(self.s.name, key, desc)
+
+    def invalid_value(
+            self,
+            key: str,
+            value: Any,
+            reason: Optional[str],
+    ) -> NoReturn:
+        if reason is None:
+            self.error(key, f"Invalid value {value!r}")
+        else:
+            self.error(key, f"Invalid value {value!r}: {reason}")
+
+    def missing_value(self, key: str) -> NoReturn:
+        self.error(key, "Missing value")
+
+
+class DefaultSection(Section):
+    def working_dir(self) -> Path:
+        # TODO Change to working dir instead of manually prepending it to paths
+        pathstr = self.s.get("working_dir", ".")
+        return Path(pathstr).expanduser()
+
+    def explain(self) -> bool:
+        return self.s.getboolean("explain", fallback=False)
+
+    def status(self) -> bool:
+        return self.s.getboolean("status", fallback=True)
+
+    def report(self) -> bool:
+        return self.s.getboolean("report", fallback=True)
+
+    def show_not_deleted(self) -> bool:
+        return self.s.getboolean("show_not_deleted", fallback=True)
+
+    def share_cookies(self) -> bool:
+        return self.s.getboolean("share_cookies", fallback=True)
+
+
+class Config:
+    @staticmethod
+    def _default_path() -> Path:
+        if os.name == "posix":
+            return Path("~/.config/PFERD/pferd.cfg").expanduser()
+        elif os.name == "nt":
+            return Path("~/AppData/Roaming/PFERD/pferd.cfg").expanduser()
+        else:
+            return Path("~/.pferd.cfg").expanduser()
+
+    def __init__(self, parser: ConfigParser):
+        self._parser = parser
+        self._default_section = DefaultSection(parser[parser.default_section])
+
+    @property
+    def default_section(self) -> DefaultSection:
+        return self._default_section
+
+    @staticmethod
+    def load_parser(parser: ConfigParser, path: Optional[Path] = None) -> None:
+        """
+        May throw a ConfigLoadError.
+        """
+
+        if path:
+            log.explain("Path specified on CLI")
+        else:
+            log.explain("Using default path")
+            path = Config._default_path()
+        log.explain(f"Loading {fmt_real_path(path)}")
+
+        # Using config.read_file instead of config.read because config.read
+        # would just ignore a missing file and carry on.
+        try:
+            with open(path, encoding="utf-8") as f:
+                parser.read_file(f, source=str(path))
+        except FileNotFoundError:
+            raise ConfigLoadError(path, "File does not exist")
+        except IsADirectoryError:
+            raise ConfigLoadError(path, "That's a directory, not a file")
+        except PermissionError:
+            raise ConfigLoadError(path, "Insufficient permissions")
+        except UnicodeDecodeError:
+            raise ConfigLoadError(path, "File is not encoded using UTF-8")
+
+    def dump(self, path: Optional[Path] = None) -> None:
+        """
+        May throw a ConfigDumpError.
+        """
+
+        if path:
+            log.explain("Using custom path")
+        else:
+            log.explain("Using default path")
+            path = self._default_path()
+
+        log.explain(f"Dumping to {fmt_real_path(path)}")
+        log.print(f"[bold bright_cyan]Dumping[/] to {escape(fmt_real_path(path))}")
+
+        try:
+            path.parent.mkdir(parents=True, exist_ok=True)
+        except PermissionError:
+            raise ConfigDumpError(path, "Could not create parent directory")
+
+        try:
+            # Ensuring we don't accidentally overwrite any existing files by
+            # always asking before overwriting a file.
+            try:
+                # x = open for exclusive creation, failing if the file already
+                # exists
+                with open(path, "x", encoding="utf-8") as f:
+                    self._parser.write(f)
+            except FileExistsError:
+                print("That file already exists.")
+                if asyncio.run(prompt_yes_no("Overwrite it?", default=False)):
+                    with open(path, "w", encoding="utf-8") as f:
+                        self._parser.write(f)
+                else:
+                    raise ConfigDumpError(path, "File already exists")
+        except IsADirectoryError:
+            raise ConfigDumpError(path, "That's a directory, not a file")
+        except PermissionError:
+            raise ConfigDumpError(path, "Insufficient permissions")
+
+    def dump_to_stdout(self) -> None:
+        self._parser.write(sys.stdout)
+
+    def crawl_sections(self) -> List[Tuple[str, SectionProxy]]:
+        result = []
+        for name, proxy in self._parser.items():
+            if name.startswith("crawl:"):
+                result.append((name, proxy))
+
+        return result
+
+    def auth_sections(self) -> List[Tuple[str, SectionProxy]]:
+        result = []
+        for name, proxy in self._parser.items():
+            if name.startswith("auth:"):
+                result.append((name, proxy))
+
+        return result

PFERD/cookie_jar.py

@@ -1,69 +0,0 @@
-"""A helper for requests cookies."""
-
-import logging
-from http.cookiejar import LoadError, LWPCookieJar
-from pathlib import Path
-from typing import Optional
-
-import requests
-
-LOGGER = logging.getLogger(__name__)
-
-
-class CookieJar:
-    """A cookie jar that can be persisted."""
-
-    def __init__(self, cookie_file: Optional[Path] = None) -> None:
-        """Create a new cookie jar at the given path.
-
-        If the path is None, the cookies will not be persisted.
-        """
-        self._cookies: LWPCookieJar
-        if cookie_file is None:
-            self._cookies = LWPCookieJar()
-        else:
-            self._cookies = LWPCookieJar(str(cookie_file.resolve()))
-
-    @property
-    def cookies(self) -> LWPCookieJar:
-        """Return the requests cookie jar."""
-        return self._cookies
-
-    def load_cookies(self) -> None:
-        """Load all cookies from the file given in the constructor."""
-        if self._cookies.filename is None:
-            return
-
-        try:
-            LOGGER.info("Loading old cookies from %s", self._cookies.filename)
-            self._cookies.load(ignore_discard=True)
-        except (FileNotFoundError, LoadError):
-            LOGGER.warning(
-                "No valid cookie file found at %s, continuing with no cookies",
-                self._cookies.filename
-            )
-
-    def save_cookies(self, reason: Optional[str] = None) -> None:
-        """Save the cookies in the file given in the constructor."""
-        if self._cookies.filename is None:
-            return
-
-        if reason is None:
-            LOGGER.info("Saving cookies")
-        else:
-            LOGGER.info("Saving cookies (%s)", reason)
-
-        # TODO figure out why ignore_discard is set
-        # TODO possibly catch a few more exceptions
-        self._cookies.save(ignore_discard=True)
-
-    def create_session(self) -> requests.Session:
-        """Create a new session using the cookie jar."""
-        sess = requests.Session()
-
-        # From the request docs: "All requests code should work out of the box
-        # with externally provided instances of CookieJar, e.g. LWPCookieJar
-        # and FileCookieJar."
-        sess.cookies = self.cookies  # type: ignore
-
-        return sess

PFERD/crawl/__init__.py

@@ -0,0 +1,25 @@
+from configparser import SectionProxy
+from typing import Callable, Dict
+
+from ..auth import Authenticator
+from ..config import Config
+from .crawler import Crawler, CrawlError, CrawlerSection  # noqa: F401
+from .ilias import KitIliasWebCrawler, KitIliasWebCrawlerSection
+from .kit_ipd_crawler import KitIpdCrawler, KitIpdCrawlerSection
+from .local_crawler import LocalCrawler, LocalCrawlerSection
+
+CrawlerConstructor = Callable[[
+    str,                       # Name (without the "crawl:" prefix)
+    SectionProxy,              # Crawler's section of global config
+    Config,                    # Global config
+    Dict[str, Authenticator],  # Loaded authenticators by name
+], Crawler]
+
+CRAWLERS: Dict[str, CrawlerConstructor] = {
+    "local": lambda n, s, c, a:
+        LocalCrawler(n, LocalCrawlerSection(s), c),
+    "kit-ilias-web": lambda n, s, c, a:
+        KitIliasWebCrawler(n, KitIliasWebCrawlerSection(s), c, a),
+    "kit-ipd": lambda n, s, c, a:
+        KitIpdCrawler(n, KitIpdCrawlerSection(s), c),
+}

PFERD/crawl/crawler.py

@@ -0,0 +1,369 @@
+import asyncio
+import os
+from abc import ABC, abstractmethod
+from collections.abc import Awaitable, Coroutine
+from datetime import datetime
+from pathlib import Path, PurePath
+from typing import Any, Callable, Dict, List, Optional, Sequence, Set, Tuple, TypeVar
+
+from ..auth import Authenticator
+from ..config import Config, Section
+from ..deduplicator import Deduplicator
+from ..limiter import Limiter
+from ..logging import ProgressBar, log
+from ..output_dir import FileSink, FileSinkToken, OnConflict, OutputDirectory, OutputDirError, Redownload
+from ..report import MarkConflictError, MarkDuplicateError, Report
+from ..transformer import Transformer
+from ..utils import ReusableAsyncContextManager, fmt_path
+
+
+class CrawlWarning(Exception):
+    pass
+
+
+class CrawlError(Exception):
+    pass
+
+
+Wrapped = TypeVar("Wrapped", bound=Callable[..., None])
+
+
+def noncritical(f: Wrapped) -> Wrapped:
+    """
+    Catches and logs a few noncritical exceptions occurring during the function
+    call, mainly CrawlWarning.
+
+    If any exception occurs during the function call, the crawler's error_free
+    variable is set to False. This includes noncritical exceptions.
+
+    Warning: Must only be applied to member functions of the Crawler class!
+    """
+
+    def wrapper(*args: Any, **kwargs: Any) -> None:
+        if not (args and isinstance(args[0], Crawler)):
+            raise RuntimeError("@noncritical must only applied to Crawler methods")
+
+        crawler = args[0]
+
+        try:
+            f(*args, **kwargs)
+        except (CrawlWarning, OutputDirError, MarkDuplicateError, MarkConflictError) as e:
+            crawler.report.add_warning(str(e))
+            log.warn(str(e))
+            crawler.error_free = False
+        except Exception as e:
+            crawler.error_free = False
+            crawler.report.add_error(str(e))
+            raise
+
+    return wrapper  # type: ignore
+
+
+AWrapped = TypeVar("AWrapped", bound=Callable[..., Coroutine[Any, Any, Optional[Any]]])
+
+
+def anoncritical(f: AWrapped) -> AWrapped:
+    """
+    An async version of @noncritical.
+
+    Catches and logs a few noncritical exceptions occurring during the function
+    call, mainly CrawlWarning.
+
+    If any exception occurs during the function call, the crawler's error_free
+    variable is set to False. This includes noncritical exceptions.
+
+    Warning: Must only be applied to member functions of the Crawler class!
+    """
+
+    async def wrapper(*args: Any, **kwargs: Any) -> Optional[Any]:
+        if not (args and isinstance(args[0], Crawler)):
+            raise RuntimeError("@anoncritical must only applied to Crawler methods")
+
+        crawler = args[0]
+
+        try:
+            return await f(*args, **kwargs)
+        except (CrawlWarning, OutputDirError, MarkDuplicateError, MarkConflictError) as e:
+            log.warn(str(e))
+            crawler.error_free = False
+            crawler.report.add_warning(str(e))
+        except Exception as e:
+            crawler.error_free = False
+            crawler.report.add_error(str(e))
+            raise
+
+        return None
+
+    return wrapper  # type: ignore
+
+
+class CrawlToken(ReusableAsyncContextManager[ProgressBar]):
+    def __init__(self, limiter: Limiter, path: PurePath):
+        super().__init__()
+
+        self._limiter = limiter
+        self._path = path
+
+    @property
+    def path(self) -> PurePath:
+        return self._path
+
+    async def _on_aenter(self) -> ProgressBar:
+        self._stack.callback(lambda: log.status("[bold cyan]", "Crawled", fmt_path(self._path)))
+        await self._stack.enter_async_context(self._limiter.limit_crawl())
+        bar = self._stack.enter_context(log.crawl_bar("[bold bright_cyan]", "Crawling", fmt_path(self._path)))
+
+        return bar
+
+
+class DownloadToken(ReusableAsyncContextManager[Tuple[ProgressBar, FileSink]]):
+    def __init__(self, limiter: Limiter, fs_token: FileSinkToken, path: PurePath):
+        super().__init__()
+
+        self._limiter = limiter
+        self._fs_token = fs_token
+        self._path = path
+
+    @property
+    def path(self) -> PurePath:
+        return self._path
+
+    async def _on_aenter(self) -> Tuple[ProgressBar, FileSink]:
+        await self._stack.enter_async_context(self._limiter.limit_download())
+        sink = await self._stack.enter_async_context(self._fs_token)
+        # The "Downloaded ..." message is printed in the output dir, not here
+        bar = self._stack.enter_context(log.download_bar("[bold bright_cyan]", "Downloading",
+                                                         fmt_path(self._path)))
+
+        return bar, sink
+
+
+class CrawlerSection(Section):
+    def type(self) -> str:
+        value = self.s.get("type")
+        if value is None:
+            self.missing_value("type")
+        return value
+
+    def skip(self) -> bool:
+        return self.s.getboolean("skip", fallback=False)
+
+    def output_dir(self, name: str) -> Path:
+        # TODO Use removeprefix() after switching to 3.9
+        if name.startswith("crawl:"):
+            name = name[len("crawl:"):]
+        return Path(self.s.get("output_dir", name)).expanduser()
+
+    def redownload(self) -> Redownload:
+        value = self.s.get("redownload", "never-smart")
+        try:
+            return Redownload.from_string(value)
+        except ValueError as e:
+            self.invalid_value(
+                "redownload",
+                value,
+                str(e).capitalize(),
+            )
+
+    def on_conflict(self) -> OnConflict:
+        value = self.s.get("on_conflict", "prompt")
+        try:
+            return OnConflict.from_string(value)
+        except ValueError as e:
+            self.invalid_value(
+                "on_conflict",
+                value,
+                str(e).capitalize(),
+            )
+
+    def transform(self) -> str:
+        return self.s.get("transform", "")
+
+    def tasks(self) -> int:
+        value = self.s.getint("tasks", fallback=1)
+        if value <= 0:
+            self.invalid_value("tasks", value, "Must be greater than 0")
+        return value
+
+    def downloads(self) -> int:
+        tasks = self.tasks()
+        value = self.s.getint("downloads", fallback=None)
+        if value is None:
+            return tasks
+        if value <= 0:
+            self.invalid_value("downloads", value, "Must be greater than 0")
+        if value > tasks:
+            self.invalid_value("downloads", value, "Must not be greater than tasks")
+        return value
+
+    def task_delay(self) -> float:
+        value = self.s.getfloat("task_delay", fallback=0.0)
+        if value < 0:
+            self.invalid_value("task_delay", value, "Must not be negative")
+        return value
+
+    def windows_paths(self) -> bool:
+        on_windows = os.name == "nt"
+        return self.s.getboolean("windows_paths", fallback=on_windows)
+
+    def auth(self, authenticators: Dict[str, Authenticator]) -> Authenticator:
+        value = self.s.get("auth")
+        if value is None:
+            self.missing_value("auth")
+        auth = authenticators.get(value)
+        if auth is None:
+            self.invalid_value("auth", value, "No such auth section exists")
+        return auth
+
+
+class Crawler(ABC):
+    def __init__(
+            self,
+            name: str,
+            section: CrawlerSection,
+            config: Config,
+    ) -> None:
+        """
+        Initialize a crawler from its name and its section in the config file.
+
+        If you are writing your own constructor for your own crawler, make sure
+        to call this constructor first (via super().__init__).
+
+        May throw a CrawlerLoadException.
+        """
+
+        self.name = name
+        self.error_free = True
+
+        self._limiter = Limiter(
+            task_limit=section.tasks(),
+            download_limit=section.downloads(),
+            task_delay=section.task_delay(),
+        )
+
+        self._deduplicator = Deduplicator(section.windows_paths())
+        self._transformer = Transformer(section.transform())
+
+        self._output_dir = OutputDirectory(
+            config.default_section.working_dir() / section.output_dir(name),
+            section.redownload(),
+            section.on_conflict(),
+        )
+
+    @property
+    def report(self) -> Report:
+        return self._output_dir.report
+
+    @property
+    def prev_report(self) -> Optional[Report]:
+        return self._output_dir.prev_report
+
+    @staticmethod
+    async def gather(awaitables: Sequence[Awaitable[Any]]) -> List[Any]:
+        """
+        Similar to asyncio.gather. However, in the case of an exception, all
+        still running tasks are cancelled and the exception is rethrown.
+
+        This should always be preferred over asyncio.gather in crawler code so
+        that an exception like CrawlError may actually stop the crawler.
+        """
+
+        tasks = [asyncio.ensure_future(aw) for aw in awaitables]
+        result = asyncio.gather(*tasks)
+        try:
+            return await result
+        except:  # noqa: E722
+            for task in tasks:
+                task.cancel()
+            raise
+
+    async def crawl(self, path: PurePath) -> Optional[CrawlToken]:
+        log.explain_topic(f"Decision: Crawl {fmt_path(path)}")
+        path = self._deduplicator.mark(path)
+        self._output_dir.report.found(path)
+
+        if self._transformer.transform(path) is None:
+            log.explain("Answer: No")
+            log.status("[bold bright_black]", "Ignored", fmt_path(path))
+            return None
+
+        log.explain("Answer: Yes")
+        return CrawlToken(self._limiter, path)
+
+    async def download(
+            self,
+            path: PurePath,
+            mtime: Optional[datetime] = None,
+            redownload: Optional[Redownload] = None,
+            on_conflict: Optional[OnConflict] = None,
+    ) -> Optional[DownloadToken]:
+        log.explain_topic(f"Decision: Download {fmt_path(path)}")
+        path = self._deduplicator.mark(path)
+        self._output_dir.report.found(path)
+
+        transformed_path = self._transformer.transform(path)
+        if transformed_path is None:
+            log.explain("Answer: No")
+            log.status("[bold bright_black]", "Ignored", fmt_path(path))
+            return None
+
+        fs_token = await self._output_dir.download(path, transformed_path, mtime, redownload, on_conflict)
+        if fs_token is None:
+            log.explain("Answer: No")
+            return None
+
+        log.explain("Answer: Yes")
+        return DownloadToken(self._limiter, fs_token, path)
+
+    async def _cleanup(self) -> None:
+        log.explain_topic("Decision: Clean up files")
+        if self.error_free:
+            log.explain("No warnings or errors occurred during this run")
+            log.explain("Answer: Yes")
+            await self._output_dir.cleanup()
+        else:
+            log.explain("Warnings or errors occurred during this run")
+            log.explain("Answer: No")
+
+    @anoncritical
+    async def run(self) -> None:
+        """
+        Start the crawling process. Call this function if you want to use a
+        crawler.
+        """
+
+        with log.show_progress():
+            self._output_dir.prepare()
+            self._output_dir.load_prev_report()
+            await self._run()
+            await self._cleanup()
+            self._output_dir.store_report()
+
+    @abstractmethod
+    async def _run(self) -> None:
+        """
+        Overwrite this function if you are writing a crawler.
+
+        This function must not return before all crawling is complete. To crawl
+        multiple things concurrently, asyncio.gather can be used.
+        """
+
+        pass
+
+    def debug_transforms(self) -> None:
+        self._output_dir.load_prev_report()
+
+        if not self.prev_report:
+            log.warn("Couldn't find or load old report")
+            return
+
+        seen: Set[PurePath] = set()
+        for known in sorted(self.prev_report.found_paths):
+            looking_at = list(reversed(known.parents)) + [known]
+            for path in looking_at:
+                if path in seen:
+                    continue
+
+                log.explain_topic(f"Transforming {fmt_path(path)}")
+                self._transformer.transform(path)
+                seen.add(path)

PFERD/crawl/http_crawler.py

@@ -0,0 +1,199 @@
+import asyncio
+import http.cookies
+import ssl
+from pathlib import Path, PurePath
+from typing import Any, Dict, List, Optional
+
+import aiohttp
+import certifi
+from aiohttp.client import ClientTimeout
+
+from ..auth import Authenticator
+from ..config import Config
+from ..logging import log
+from ..utils import fmt_real_path
+from ..version import NAME, VERSION
+from .crawler import Crawler, CrawlerSection
+
+
+class HttpCrawlerSection(CrawlerSection):
+    def http_timeout(self) -> float:
+        return self.s.getfloat("http_timeout", fallback=20)
+
+
+class HttpCrawler(Crawler):
+    COOKIE_FILE = PurePath(".cookies")
+
+    def __init__(
+            self,
+            name: str,
+            section: HttpCrawlerSection,
+            config: Config,
+            shared_auth: Optional[Authenticator] = None,
+    ) -> None:
+        super().__init__(name, section, config)
+
+        self._authentication_id = 0
+        self._authentication_lock = asyncio.Lock()
+        self._request_count = 0
+        self._http_timeout = section.http_timeout()
+
+        self._cookie_jar_path = self._output_dir.resolve(self.COOKIE_FILE)
+        self._shared_cookie_jar_paths: Optional[List[Path]] = None
+        self._shared_auth = shared_auth
+
+        self._output_dir.register_reserved(self.COOKIE_FILE)
+
+    async def _current_auth_id(self) -> int:
+        """
+        Returns the id for the current authentication, i.e. an identifier for the last
+        successful call to [authenticate].
+
+        This method must be called before any request that might authenticate is made, so the
+        HttpCrawler can properly track when [authenticate] can return early and when actual
+        authentication is necessary.
+        """
+        # We acquire the lock here to ensure we wait for any concurrent authenticate to finish.
+        # This should reduce the amount of requests we make: If an authentication is in progress
+        # all future requests wait for authentication to complete.
+        async with self._authentication_lock:
+            self._request_count += 1
+            return self._authentication_id
+
+    async def authenticate(self, caller_auth_id: int) -> None:
+        """
+        Starts the authentication process. The main work is offloaded to _authenticate, which
+        you should overwrite in a subclass if needed. This method should *NOT* be overwritten.
+
+        The [caller_auth_id] should be the result of a [_current_auth_id] call made *before*
+        the request was made. This ensures that authentication is not performed needlessly.
+        """
+        async with self._authentication_lock:
+            log.explain_topic("Authenticating")
+            # Another thread successfully called authenticate in-between
+            # We do not want to perform auth again, so we return here. We can
+            # assume the other thread suceeded as authenticate will throw an error
+            # if it failed and aborts the crawl process.
+            if caller_auth_id != self._authentication_id:
+                log.explain(
+                    "Authentication skipped due to auth id mismatch."
+                    "A previous authentication beat us to the race."
+                )
+                return
+            log.explain("Calling crawler-specific authenticate")
+            await self._authenticate()
+            self._authentication_id += 1
+            # Saving the cookies after the first auth ensures we won't need to re-authenticate
+            # on the next run, should this one be aborted or crash
+            self._save_cookies()
+
+    async def _authenticate(self) -> None:
+        """
+        Performs authentication. This method must only return normally if authentication suceeded.
+        In all other cases it must either retry internally or throw a terminal exception.
+        """
+        raise RuntimeError("_authenticate() was called but crawler doesn't provide an implementation")
+
+    def share_cookies(self, shared: Dict[Authenticator, List[Path]]) -> None:
+        if not self._shared_auth:
+            return
+
+        if self._shared_auth in shared:
+            self._shared_cookie_jar_paths = shared[self._shared_auth]
+        else:
+            self._shared_cookie_jar_paths = []
+            shared[self._shared_auth] = self._shared_cookie_jar_paths
+
+        self._shared_cookie_jar_paths.append(self._cookie_jar_path)
+
+    def _load_cookies_from_file(self, path: Path) -> None:
+        jar: Any = http.cookies.SimpleCookie()
+        with open(path, encoding="utf-8") as f:
+            for i, line in enumerate(f):
+                # Names of headers are case insensitive
+                if line[:11].lower() == "set-cookie:":
+                    jar.load(line[11:])
+                else:
+                    log.explain(f"Line {i} doesn't start with 'Set-Cookie:', ignoring it")
+        self._cookie_jar.update_cookies(jar)
+
+    def _save_cookies_to_file(self, path: Path) -> None:
+        jar: Any = http.cookies.SimpleCookie()
+        for morsel in self._cookie_jar:
+            jar[morsel.key] = morsel
+        with open(path, "w", encoding="utf-8") as f:
+            f.write(jar.output(sep="\n"))
+            f.write("\n")  # A trailing newline is just common courtesy
+
+    def _load_cookies(self) -> None:
+        log.explain_topic("Loading cookies")
+
+        cookie_jar_path: Optional[Path] = None
+
+        if self._shared_cookie_jar_paths is None:
+            log.explain("Not sharing any cookies")
+            cookie_jar_path = self._cookie_jar_path
+        else:
+            log.explain("Sharing cookies")
+            max_mtime: Optional[float] = None
+            for path in self._shared_cookie_jar_paths:
+                if not path.is_file():
+                    log.explain(f"{fmt_real_path(path)} is not a file")
+                    continue
+                mtime = path.stat().st_mtime
+                if max_mtime is None or mtime > max_mtime:
+                    log.explain(f"{fmt_real_path(path)} has newest mtime so far")
+                    max_mtime = mtime
+                    cookie_jar_path = path
+                else:
+                    log.explain(f"{fmt_real_path(path)} has older mtime")
+
+        if cookie_jar_path is None:
+            log.explain("Couldn't find a suitable cookie file")
+            return
+
+        log.explain(f"Loading cookies from {fmt_real_path(cookie_jar_path)}")
+        try:
+            self._load_cookies_from_file(cookie_jar_path)
+        except Exception as e:
+            log.explain("Failed to load cookies")
+            log.explain(str(e))
+
+    def _save_cookies(self) -> None:
+        log.explain_topic("Saving cookies")
+
+        try:
+            log.explain(f"Saving cookies to {fmt_real_path(self._cookie_jar_path)}")
+            self._save_cookies_to_file(self._cookie_jar_path)
+        except Exception as e:
+            log.warn(f"Failed to save cookies to {fmt_real_path(self._cookie_jar_path)}")
+            log.warn(str(e))
+
+    async def run(self) -> None:
+        self._request_count = 0
+        self._cookie_jar = aiohttp.CookieJar()
+        self._load_cookies()
+
+        async with aiohttp.ClientSession(
+                headers={"User-Agent": f"{NAME}/{VERSION}"},
+                cookie_jar=self._cookie_jar,
+                connector=aiohttp.TCPConnector(ssl=ssl.create_default_context(cafile=certifi.where())),
+                timeout=ClientTimeout(
+                    # 30 minutes. No download in the history of downloads was longer than 30 minutes.
+                    # This is enough to transfer a 600 MB file over a 3 Mib/s connection.
+                    # Allowing an arbitrary value could be annoying for overnight batch jobs
+                    total=15 * 60,
+                    connect=self._http_timeout,
+                    sock_connect=self._http_timeout,
+                    sock_read=self._http_timeout,
+                )
+        ) as session:
+            self.session = session
+            try:
+                await super().run()
+            finally:
+                del self.session
+        log.explain_topic(f"Total amount of HTTP requests: {self._request_count}")
+
+        # They are saved in authenticate, but a final save won't hurt
+        self._save_cookies()

PFERD/crawl/ilias/__init__.py

@@ -0,0 +1,3 @@
+from .kit_ilias_web_crawler import KitIliasWebCrawler, KitIliasWebCrawlerSection
+
+__all__ = ["KitIliasWebCrawler", "KitIliasWebCrawlerSection"]

PFERD/crawl/ilias/file_templates.py

@@ -0,0 +1,201 @@
+from enum import Enum
+from typing import Optional
+
+import bs4
+
+from PFERD.utils import soupify
+
+_link_template_plain = "{{link}}"
+_link_template_fancy = """
+<!DOCTYPE html>
+<html lang="en">
+    <head>
+        <meta charset="UTF-8">
+        <title>ILIAS - Link: {{name}}</title>
+        <meta http-equiv = "refresh" content = "{{redirect_delay}}; url = {{link}}" />
+    </head>
+
+    <style>
+    * {
+        box-sizing: border-box;
+    }
+    .center-flex {
+        display: flex;
+        align-items: center;
+        justify-content: center;
+    }
+    body {
+        padding: 0;
+        margin: 0;
+        background-color: #f0f0f0;
+        font-family: "Open Sans", Verdana, Arial, Helvetica, sans-serif;
+        height: 100vh;
+    }
+    .row {
+        background-color: white;
+        min-width: 500px;
+        max-width: 90vw;
+        display: flex;
+        padding: 1em;
+    }
+    .logo {
+        flex: 0 1;
+        margin-right: 1em;
+        fill: #009682;
+    }
+    .tile {
+        flex: 1 0;
+        display: flex;
+        flex-direction: column;
+        justify-content: center;
+    }
+    .top-row {
+        padding-bottom: 5px;
+        font-size: 15px;
+    }
+    a {
+        color: #009682;
+        text-decoration: none;
+    }
+    a:hover {
+        text-decoration: underline;
+    }
+    .bottom-row {
+        font-size: 13px;
+    }
+    .menu-button {
+        border: 1px solid black;
+        margin-left: 4em;
+        width: 25px;
+        height: 25px;
+        flex: 0 0 25px;
+        background-color: #b3e0da;
+        font-size: 13px;
+        color: #222;
+    }
+    </style>
+    <body class="center-flex">
+        <div class="row">
+            <div class="logo center-flex">
+                <svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24">
+                    <path d="M12 0c-6.627 0-12 5.373-12 12s5.373 12 12 12 12-5.373 12-12-5.373-12-12-12zm9.567 9.098c-.059-.058-.127-.108-.206-.138-.258-.101-1.35.603-1.515.256-.108-.231-.327.148-.578.008-.121-.067-.459-.52-.611-.465-.312.112.479.974.694 1.087.203-.154.86-.469 1.002-.039.271.812-.745 1.702-1.264 2.171-.775.702-.63-.454-1.159-.86-.277-.213-.274-.667-.555-.824-.125-.071-.7-.732-.694-.821l-.017.167c-.095.072-.297-.27-.319-.325 0 .298.485.772.646 1.011.273.409.42 1.005.756 1.339.179.18.866.923 1.045.908l.921-.437c.649.154-1.531 3.237-1.738 3.619-.171.321.139 1.112.114 1.49-.029.437-.374.579-.7.817-.35.255-.268.752-.562.934-.521.321-.897 1.366-1.639 1.361-.219-.001-1.151.364-1.273.007-.095-.258-.223-.455-.356-.71-.131-.25-.015-.51-.175-.731-.11-.154-.479-.502-.513-.684-.002-.157.118-.632.283-.715.231-.118.044-.462.016-.663-.048-.357-.27-.652-.535-.859-.393-.302-.189-.542-.098-.974 0-.206-.126-.476-.402-.396-.57.166-.396-.445-.812-.417-.299.021-.543.211-.821.295-.349.104-.707-.083-1.053-.126-1.421-.179-1.885-1.804-1.514-2.976.037-.192-.115-.547-.048-.696.159-.352.485-.752.768-1.021.16-.152.365-.113.553-.231.29-.182.294-.558.578-.789.404-.328.956-.321 1.482-.392.281-.037 1.35-.268 1.518-.06 0 .039.193.611-.019.578.438.023 1.061.756 1.476.585.213-.089.135-.744.573-.427.265.19 1.45.275 1.696.07.152-.125.236-.939.053-1.031.117.116-.618.125-.686.099-.122-.044-.235.115-.43.025.117.055-.651-.358-.22-.674-.181.132-.349-.037-.544.109-.135.109.062.181-.13.277-.305.155-.535-.53-.649-.607-.118-.077-1.024-.713-.777-.298l.797.793c-.04.026-.209-.289-.209-.059.053-.136.02.585-.105.35-.056-.09.091-.14.006-.271 0-.085-.23-.169-.275-.228-.126-.157-.462-.502-.644-.585-.05-.024-.771.088-.832.111-.071.099-.131.203-.181.314-.149.055-.29.127-.423.216l-.159.356c-.068.061-.772.294-.776.303.03-.076-.492-.172-.457-.324.038-.167.215-.687.169-.877-.048-.199 1.085.287 1.158-.238.029-.227.047-.492-.316-.531.069.008.702-.249.807-.364.148-.169.486-.447.731-.447.286 0 .225-.417.356-.622.133.053-.071.38.088.512-.01-.104.45.057.494.033.105-.056.691-.023.601-.299-.101-.28.052-.197.183-.255-.02.008.248-.458.363-.456-.104-.089-.398.112-.516.103-.308-.024-.177-.525-.061-.672.09-.116-.246-.258-.25-.036-.006.332-.314.633-.243 1.075.109.666-.743-.161-.816-.115-.283.172-.515-.216-.368-.449.149-.238.51-.226.659-.48.104-.179.227-.389.388-.524.541-.454.689-.091 1.229-.042.526.048.178.125.105.327-.07.192.289.261.413.1.071-.092.232-.326.301-.499.07-.175.578-.2.527-.365 2.72 1.148 4.827 3.465 5.694 6.318zm-11.113-3.779l.068-.087.073-.019c.042-.034.086-.118.151-.104.043.009.146.095.111.148-.037.054-.066-.049-.081.101-.018.169-.188.167-.313.222-.087.037-.175-.018-.09-.104l.088-.108-.007-.049zm.442.245c.046-.045.138-.008.151-.094.014-.084.078-.178-.008-.335-.022-.042.116-.082.051-.137l-.109.032s.155-.668.364-.366l-.089.103c.135.134.172.47.215.687.127.066.324.078.098.192.117-.02-.618.314-.715.178-.072-.083.317-.139.307-.173-.004-.011-.317-.02-.265-.087zm1.43-3.547l-.356.326c-.36.298-1.28.883-1.793.705-.524-.18-1.647.667-1.826.673-.067.003.002-.641.36-.689-.141.021.993-.575 1.185-.805.678-.146 1.381-.227 2.104-.227l.326.017zm-5.086 1.19c.07.082.278.092-.026.288-.183.11-.377.809-.548.809-.51.223-.542-.439-1.109.413-.078.115-.395.158-.644.236.685-.688 1.468-1.279 2.327-1.746zm-5.24 8.793c0-.541.055-1.068.139-1.586l.292.185c.113.135.113.719.169.911.139.482.484.751.748 1.19.155.261.414.923.332 1.197.109-.179 1.081.824 1.259 1.033.418.492.74 1.088.061 1.574-.219.158.334 1.14.049 1.382l-.365.094c-.225.138-.235.397-.166.631-1.562-1.765-2.518-4.076-2.518-6.611zm14.347-5.823c.083-.01-.107.167-.107.167.033.256.222.396.581.527.437.157.038.455-.213.385-.139-.039-.854-.255-.879.025 0 .167-.679.001-.573-.175.073-.119.05-.387.186-.562.193-.255.38-.116.386.032-.001.394.398-.373.619-.399z"/>
+                </svg>
+            </div>
+            <div class="tile">
+                <div class="top-row">
+                    <a href="{{link}}">{{name}}</a>
+                </div>
+                <div class="bottom-row">{{description}}</div>
+            </div>
+            <div class="menu-button center-flex"> ⯆ </div>
+        </div>
+    </body>
+</html>
+""".strip()  # noqa: E501 line too long
+
+_link_template_internet_shortcut = """
+[InternetShortcut]
+URL={{link}}
+""".strip()
+
+_learning_module_template = """
+<!DOCTYPE html>
+<html lang="en">
+    <head>
+        <meta charset="UTF-8">
+        <title>{{name}}</title>
+    </head>
+
+    <style>
+    * {
+        box-sizing: border-box;
+    }
+    .center-flex {
+        display: flex;
+        align-items: center;
+        justify-content: center;
+    }
+    .nav {
+        display: flex;
+        justify-content: space-between;
+    }
+    </style>
+    <body class="center-flex">
+{{body}}
+    </body>
+</html>
+"""
+
+
+def learning_module_template(body: bs4.Tag, name: str, prev: Optional[str], next: Optional[str]) -> str:
+    # Seems to be comments, ignore those.
+    for elem in body.select(".il-copg-mob-fullscreen-modal"):
+        elem.decompose()
+
+    nav_template = """
+        <div class="nav">
+            {{left}}
+            {{right}}
+        </div>
+    """
+    if prev and body.select_one(".ilc_page_lnav_LeftNavigation"):
+        text = body.select_one(".ilc_page_lnav_LeftNavigation").getText().strip()
+        left = f'<a href="{prev}">{text}</a>'
+    else:
+        left = "<span></span>"
+
+    if next and body.select_one(".ilc_page_rnav_RightNavigation"):
+        text = body.select_one(".ilc_page_rnav_RightNavigation").getText().strip()
+        right = f'<a href="{next}">{text}</a>'
+    else:
+        right = "<span></span>"
+
+    if top_nav := body.select_one(".ilc_page_tnav_TopNavigation"):
+        top_nav.replace_with(
+            soupify(nav_template.replace("{{left}}", left).replace("{{right}}", right).encode())
+        )
+
+    if bot_nav := body.select_one(".ilc_page_bnav_BottomNavigation"):
+        bot_nav.replace_with(soupify(nav_template.replace(
+            "{{left}}", left).replace("{{right}}", right).encode())
+        )
+
+    body = body.prettify()
+    return _learning_module_template.replace("{{body}}", body).replace("{{name}}", name)
+
+
+class Links(Enum):
+    IGNORE = "ignore"
+    PLAINTEXT = "plaintext"
+    FANCY = "fancy"
+    INTERNET_SHORTCUT = "internet-shortcut"
+
+    def template(self) -> Optional[str]:
+        if self == Links.FANCY:
+            return _link_template_fancy
+        elif self == Links.PLAINTEXT:
+            return _link_template_plain
+        elif self == Links.INTERNET_SHORTCUT:
+            return _link_template_internet_shortcut
+        elif self == Links.IGNORE:
+            return None
+        raise ValueError("Missing switch case")
+
+    def extension(self) -> Optional[str]:
+        if self == Links.FANCY:
+            return ".html"
+        elif self == Links.PLAINTEXT:
+            return ".txt"
+        elif self == Links.INTERNET_SHORTCUT:
+            return ".url"
+        elif self == Links.IGNORE:
+            return None
+        raise ValueError("Missing switch case")
+
+    @staticmethod
+    def from_string(string: str) -> "Links":
+        try:
+            return Links(string)
+        except ValueError:
+            raise ValueError("must be one of 'ignore', 'plaintext',"
+                             " 'html', 'internet-shortcut'")

PFERD/crawl/ilias/ilias_html_cleaner.py

@@ -0,0 +1,91 @@
+from bs4 import BeautifulSoup, Comment, Tag
+
+_STYLE_TAG_CONTENT = """
+    .ilc_text_block_Information {
+      background-color: #f5f7fa;
+    }
+    div.ilc_text_block_Standard {
+      margin-bottom: 10px;
+      margin-top: 10px;
+    }
+    span.ilc_text_inline_Strong {
+      font-weight: bold;
+    }
+
+    .accordion-head {
+      background-color: #f5f7fa;
+      padding: 0.5rem 0;
+    }
+
+    h3 {
+      margin-top: 0.5rem;
+      margin-bottom: 1rem;
+    }
+
+    br.visible-break {
+      margin-bottom: 1rem;
+    }
+
+    article {
+      margin: 0.5rem 0;
+    }
+
+    body {
+      padding: 1em;
+      grid-template-columns: 1fr min(60rem, 90%) 1fr;
+      line-height: 1.2;
+    }
+"""
+
+_ARTICLE_WORTHY_CLASSES = [
+    "ilc_text_block_Information",
+    "ilc_section_Attention",
+    "ilc_section_Link",
+]
+
+
+def insert_base_markup(soup: BeautifulSoup) -> BeautifulSoup:
+    head = soup.new_tag("head")
+    soup.insert(0, head)
+
+    simplecss_link: Tag = soup.new_tag("link")
+    # <link rel="stylesheet" href="https://cdn.simplecss.org/simple.css">
+    simplecss_link["rel"] = "stylesheet"
+    simplecss_link["href"] = "https://cdn.simplecss.org/simple.css"
+    head.append(simplecss_link)
+
+    # Basic style tags for compat
+    style: Tag = soup.new_tag("style")
+    style.append(_STYLE_TAG_CONTENT)
+    head.append(style)
+
+    return soup
+
+
+def clean(soup: BeautifulSoup) -> BeautifulSoup:
+    for block in soup.find_all(class_=lambda x: x in _ARTICLE_WORTHY_CLASSES):
+        block.name = "article"
+
+    for block in soup.find_all("h3"):
+        block.name = "div"
+
+    for block in soup.find_all("h1"):
+        block.name = "h3"
+
+    for block in soup.find_all(class_="ilc_va_ihcap_VAccordIHeadCap"):
+        block.name = "h3"
+        block["class"] += ["accordion-head"]
+
+    for dummy in soup.select(".ilc_text_block_Standard.ilc_Paragraph"):
+        children = list(dummy.children)
+        if not children:
+            dummy.decompose()
+        if len(children) > 1:
+            continue
+        if isinstance(type(children[0]), Comment):
+            dummy.decompose()
+
+    for hrule_imposter in soup.find_all(class_="ilc_section_Separator"):
+        hrule_imposter.insert(0, soup.new_tag("hr"))
+
+    return soup

PFERD/crawl/kit_ipd_crawler.py

@@ -0,0 +1,170 @@
+import os
+import re
+from dataclasses import dataclass
+from pathlib import PurePath
+from typing import Awaitable, List, Optional, Pattern, Set, Tuple, Union
+from urllib.parse import urljoin
+
+from bs4 import BeautifulSoup, Tag
+
+from ..config import Config
+from ..logging import ProgressBar, log
+from ..output_dir import FileSink
+from ..utils import soupify
+from .crawler import CrawlError
+from .http_crawler import HttpCrawler, HttpCrawlerSection
+
+
+class KitIpdCrawlerSection(HttpCrawlerSection):
+    def target(self) -> str:
+        target = self.s.get("target")
+        if not target:
+            self.missing_value("target")
+
+        if not target.startswith("https://"):
+            self.invalid_value("target", target, "Should be a URL")
+
+        return target
+
+    def link_regex(self) -> Pattern[str]:
+        regex = self.s.get("link_regex", r"^.*?[^/]+\.(pdf|zip|c|cpp|java)$")
+        return re.compile(regex)
+
+
+@dataclass(unsafe_hash=True)
+class KitIpdFile:
+    name: str
+    url: str
+
+
+@dataclass
+class KitIpdFolder:
+    name: str
+    files: List[KitIpdFile]
+
+    def explain(self) -> None:
+        log.explain_topic(f"Folder {self.name!r}")
+        for file in self.files:
+            log.explain(f"File {file.name!r} (href={file.url!r})")
+
+    def __hash__(self) -> int:
+        return self.name.__hash__()
+
+
+class KitIpdCrawler(HttpCrawler):
+
+    def __init__(
+            self,
+            name: str,
+            section: KitIpdCrawlerSection,
+            config: Config,
+    ):
+        super().__init__(name, section, config)
+        self._url = section.target()
+        self._file_regex = section.link_regex()
+
+    async def _run(self) -> None:
+        maybe_cl = await self.crawl(PurePath("."))
+        if not maybe_cl:
+            return
+
+        tasks: List[Awaitable[None]] = []
+
+        async with maybe_cl:
+            for item in await self._fetch_items():
+                if isinstance(item, KitIpdFolder):
+                    tasks.append(self._crawl_folder(item))
+                else:
+                    # Orphan files are placed in the root folder
+                    tasks.append(self._download_file(PurePath("."), item))
+
+        await self.gather(tasks)
+
+    async def _crawl_folder(self, folder: KitIpdFolder) -> None:
+        path = PurePath(folder.name)
+        if not await self.crawl(path):
+            return
+
+        tasks = [self._download_file(path, file) for file in folder.files]
+
+        await self.gather(tasks)
+
+    async def _download_file(self, parent: PurePath, file: KitIpdFile) -> None:
+        element_path = parent / file.name
+        maybe_dl = await self.download(element_path)
+        if not maybe_dl:
+            return
+
+        async with maybe_dl as (bar, sink):
+            await self._stream_from_url(file.url, sink, bar)
+
+    async def _fetch_items(self) -> Set[Union[KitIpdFile, KitIpdFolder]]:
+        page, url = await self.get_page()
+        elements: List[Tag] = self._find_file_links(page)
+        items: Set[Union[KitIpdFile, KitIpdFolder]] = set()
+
+        for element in elements:
+            folder_label = self._find_folder_label(element)
+            if folder_label:
+                folder = self._extract_folder(folder_label, url)
+                if folder not in items:
+                    items.add(folder)
+                    folder.explain()
+            else:
+                file = self._extract_file(element, url)
+                items.add(file)
+                log.explain_topic(f"Orphan file {file.name!r} (href={file.url!r})")
+                log.explain("Attributing it to root folder")
+
+        return items
+
+    def _extract_folder(self, folder_tag: Tag, url: str) -> KitIpdFolder:
+        files: List[KitIpdFile] = []
+        name = folder_tag.getText().strip()
+
+        container: Tag = folder_tag.findNextSibling(name="table")
+        for link in self._find_file_links(container):
+            files.append(self._extract_file(link, url))
+
+        return KitIpdFolder(name, files)
+
+    @staticmethod
+    def _find_folder_label(file_link: Tag) -> Optional[Tag]:
+        enclosing_table: Tag = file_link.findParent(name="table")
+        if enclosing_table is None:
+            return None
+        return enclosing_table.findPreviousSibling(name=re.compile("^h[1-6]$"))
+
+    def _extract_file(self, link: Tag, url: str) -> KitIpdFile:
+        url = self._abs_url_from_link(url, link)
+        name = os.path.basename(url)
+        return KitIpdFile(name, url)
+
+    def _find_file_links(self, tag: Union[Tag, BeautifulSoup]) -> List[Tag]:
+        return tag.findAll(name="a", attrs={"href": self._file_regex})
+
+    def _abs_url_from_link(self, url: str, link_tag: Tag) -> str:
+        return urljoin(url, link_tag.get("href"))
+
+    async def _stream_from_url(self, url: str, sink: FileSink, bar: ProgressBar) -> None:
+        async with self.session.get(url, allow_redirects=False) as resp:
+            if resp.status == 403:
+                raise CrawlError("Received a 403. Are you within the KIT network/VPN?")
+            if resp.content_length:
+                bar.set_total(resp.content_length)
+
+            async for data in resp.content.iter_chunked(1024):
+                sink.file.write(data)
+                bar.advance(len(data))
+
+            sink.done()
+
+    async def get_page(self) -> Tuple[BeautifulSoup, str]:
+        async with self.session.get(self._url) as request:
+            # The web page for Algorithmen für Routenplanung contains some
+            # weird comments that beautifulsoup doesn't parse correctly. This
+            # hack enables those pages to be crawled, and should hopefully not
+            # cause issues on other pages.
+            content = (await request.read()).decode("utf-8")
+            content = re.sub(r"<!--.*?-->", "", content)
+            return soupify(content.encode("utf-8")), str(request.url)

PFERD/crawl/local_crawler.py

@@ -0,0 +1,117 @@
+import asyncio
+import datetime
+import random
+from pathlib import Path, PurePath
+from typing import Optional
+
+from ..config import Config
+from .crawler import Crawler, CrawlerSection, anoncritical
+
+
+class LocalCrawlerSection(CrawlerSection):
+    def target(self) -> Path:
+        value = self.s.get("target")
+        if value is None:
+            self.missing_value("target")
+        return Path(value).expanduser()
+
+    def crawl_delay(self) -> float:
+        value = self.s.getfloat("crawl_delay", fallback=0.0)
+        if value < 0:
+            self.invalid_value("crawl_delay", value,
+                               "Must not be negative")
+        return value
+
+    def download_delay(self) -> float:
+        value = self.s.getfloat("download_delay", fallback=0.0)
+        if value < 0:
+            self.invalid_value("download_delay", value,
+                               "Must not be negative")
+        return value
+
+    def download_speed(self) -> Optional[int]:
+        value = self.s.getint("download_speed")
+        if value is not None and value <= 0:
+            self.invalid_value("download_speed", value,
+                               "Must be greater than 0")
+        return value
+
+
+class LocalCrawler(Crawler):
+    def __init__(
+            self,
+            name: str,
+            section: LocalCrawlerSection,
+            config: Config,
+    ):
+        super().__init__(name, section, config)
+
+        self._target = config.default_section.working_dir() / section.target()
+        self._crawl_delay = section.crawl_delay()
+        self._download_delay = section.download_delay()
+        self._download_speed = section.download_speed()
+
+        if self._download_speed:
+            self._block_size = self._download_speed // 10
+        else:
+            self._block_size = 1024**2  # 1 MiB
+
+    async def _run(self) -> None:
+        await self._crawl_path(self._target, PurePath())
+
+    @anoncritical
+    async def _crawl_path(self, path: Path, pure: PurePath) -> None:
+        if path.is_dir():
+            await self._crawl_dir(path, pure)
+        elif path.is_file():
+            await self._crawl_file(path, pure)
+
+    async def _crawl_dir(self, path: Path, pure: PurePath) -> None:
+        cl = await self.crawl(pure)
+        if not cl:
+            return
+
+        tasks = []
+
+        async with cl:
+            await asyncio.sleep(random.uniform(
+                0.5 * self._crawl_delay,
+                self._crawl_delay,
+            ))
+
+            for child in path.iterdir():
+                pure_child = cl.path / child.name
+                tasks.append(self._crawl_path(child, pure_child))
+
+        await self.gather(tasks)
+
+    async def _crawl_file(self, path: Path, pure: PurePath) -> None:
+        stat = path.stat()
+        mtime = datetime.datetime.fromtimestamp(stat.st_mtime)
+        dl = await self.download(pure, mtime=mtime)
+        if not dl:
+            return
+
+        async with dl as (bar, sink):
+            await asyncio.sleep(random.uniform(
+                0.5 * self._download_delay,
+                self._download_delay,
+            ))
+
+            bar.set_total(stat.st_size)
+
+            with open(path, "rb") as f:
+                while True:
+                    data = f.read(self._block_size)
+                    if len(data) == 0:
+                        break
+
+                    sink.file.write(data)
+                    bar.advance(len(data))
+
+                    if self._download_speed:
+                        delay = self._block_size / self._download_speed
+                        delay = random.uniform(0.8 * delay, 1.2 * delay)
+                        await asyncio.sleep(delay)
+
+                sink.done()

PFERD/deduplicator.py

@@ -0,0 +1,85 @@
+from pathlib import PurePath
+from typing import Iterator, Set
+
+from .logging import log
+from .utils import fmt_path
+
+
+def name_variants(path: PurePath) -> Iterator[PurePath]:
+    separator = " " if " " in path.stem else "_"
+    i = 1
+    while True:
+        yield path.parent / f"{path.stem}{separator}{i}{path.suffix}"
+        i += 1
+
+
+class Deduplicator:
+    FORBIDDEN_CHARS = '<>:"/\\|?*' + "".join([chr(i) for i in range(0, 32)])
+    FORBIDDEN_NAMES = {
+        "CON", "PRN", "AUX", "NUL",
+        "COM1", "COM2", "COM3", "COM4", "COM5", "COM6", "COM7", "COM8", "COM9",
+        "LPT1", "LPT2", "LPT3", "LPT4", "LPT5", "LPT6", "LPT7", "LPT8", "LPT9",
+    }
+
+    def __init__(self, windows_paths: bool) -> None:
+        self._windows_paths = windows_paths
+
+        self._known: Set[PurePath] = set()
+
+    def _add(self, path: PurePath) -> None:
+        self._known.add(path)
+
+        # The last parent is just "."
+        for parent in list(path.parents)[:-1]:
+            self._known.add(parent)
+
+    def _fixup_element(self, name: str) -> str:
+        # For historical reasons, windows paths have some odd restrictions that
+        # we're trying to avoid. See:
+        # https://docs.microsoft.com/en-us/windows/win32/fileio/naming-a-file
+
+        for char in self.FORBIDDEN_CHARS:
+            name = name.replace(char, "_")
+
+        path = PurePath(name)
+        if path.stem in self.FORBIDDEN_NAMES:
+            name = f"{path.stem}_{path.suffix}"
+
+        if name.endswith(" ") or name.endswith("."):
+            name += "_"
+
+        return name
+
+    def _fixup_for_windows(self, path: PurePath) -> PurePath:
+        new_path = PurePath(*[self._fixup_element(elem) for elem in path.parts])
+        if new_path != path:
+            log.explain(f"Changed path to {fmt_path(new_path)} for windows compatibility")
+        return new_path
+
+    def fixup_path(self, path: PurePath) -> PurePath:
+        """Fixes up the path for windows, if enabled. Returns the path unchanged otherwise."""
+        if self._windows_paths:
+            return self._fixup_for_windows(path)
+        return path
+
+    def mark(self, path: PurePath) -> PurePath:
+        if self._windows_paths:
+            path = self._fixup_for_windows(path)
+
+        if path not in self._known:
+            self._add(path)
+            return path
+
+        log.explain(f"Path {fmt_path(path)} is already taken, finding a new name")
+
+        for variant in name_variants(path):
+            if variant in self._known:
+                log.explain(f"Path {fmt_path(variant)} is taken as well")
+                continue
+
+            log.explain(f"Found unused path {fmt_path(variant)}")
+            self._add(variant)
+            return variant
+
+        # The "name_variants" iterator returns infinitely many paths
+        raise RuntimeError("Unreachable")

PFERD/diva.py

@@ -1,169 +0,0 @@
-"""
-Utility functions and a scraper/downloader for the KIT DIVA portal.
-"""
-import logging
-import re
-from dataclasses import dataclass
-from pathlib import Path
-from typing import Any, Callable, List, Optional
-
-import requests
-
-from .errors import FatalException
-from .logging import PrettyLogger
-from .organizer import Organizer
-from .tmp_dir import TmpDir
-from .transform import Transformable
-from .utils import stream_to_path
-
-LOGGER = logging.getLogger(__name__)
-PRETTY = PrettyLogger(LOGGER)
-
-
-@dataclass
-class DivaDownloadInfo(Transformable):
-    """
-    Information about a DIVA video
-    """
-    url: str
-
-
-DivaDownloadStrategy = Callable[[Organizer, DivaDownloadInfo], bool]
-
-
-def diva_download_new(organizer: Organizer, info: DivaDownloadInfo) -> bool:
-    """
-    Accepts only new files.
-    """
-    resolved_file = organizer.resolve(info.path)
-    if not resolved_file.exists():
-        return True
-    PRETTY.ignored_file(info.path, "local file exists")
-    return False
-
-
-class DivaPlaylistCrawler:
-    # pylint: disable=too-few-public-methods
-    """
-    A crawler for DIVA playlists.
-    """
-
-    _PLAYLIST_BASE_URL = "https://mediaservice.bibliothek.kit.edu/asset/detail/"
-    _COLLECTION_BASE_URL = "https://mediaservice.bibliothek.kit.edu/asset/collection.json"
-
-    def __init__(self, playlist_id: str):
-        self._id = playlist_id
-
-    @classmethod
-    def fetch_id(cls, playlist_link: str) -> str:
-        """
-        Fetches the ID for a playerlist, given the base link
-        (e.g. https://mediaservice.bibliothek.kit.edu/#/details/DIVA-2019-271).
-
-        Raises a FatalException, if the id can not be resolved
-        """
-        match = re.match(r".+#/details/(.+)", playlist_link)
-        if match is None:
-            raise FatalException(
-                "DIVA: Invalid playlist link format, could not extract details."
-            )
-        base_name = match.group(1)
-
-        response = requests.get(cls._PLAYLIST_BASE_URL + base_name + ".json")
-
-        if response.status_code != 200:
-            raise FatalException(
-                f"DIVA: Got non-200 status code ({response.status_code}))"
-                f"when requesting {response.url!r}!"
-            )
-
-        body = response.json()
-
-        if body["error"]:
-            raise FatalException(f"DIVA: Server returned error {body['error']!r}.")
-
-        return body["result"]["collection"]["id"]
-
-    def crawl(self) -> List[DivaDownloadInfo]:
-        """
-        Crawls the playlist given in the constructor.
-        """
-        response = requests.get(self._COLLECTION_BASE_URL, params={"collection": self._id})
-        if response.status_code != 200:
-            raise FatalException(f"Server returned status {response.status_code}.")
-
-        body = response.json()
-
-        if body["error"]:
-            raise FatalException(f"Server returned error {body['error']!r}.")
-
-        result = body["result"]
-
-        if result["resultCount"] > result["pageSize"]:
-            PRETTY.warning("Did not receive all results, some will be missing")
-
-        download_infos: List[DivaDownloadInfo] = []
-
-        for video in result["resultList"]:
-            title = video["title"]
-            collection_title = self._follow_path(["collection", "title"], video)
-            url = self._follow_path(
-                ["resourceList", "derivateList", "mp4", "url"],
-                video
-            )
-
-            if url and collection_title and title:
-                path = Path(collection_title, title + ".mp4")
-                download_infos.append(DivaDownloadInfo(path, url))
-            else:
-                PRETTY.warning(f"Incomplete video found: {title!r} {collection_title!r} {url!r}")
-
-        return download_infos
-
-    @staticmethod
-    def _follow_path(path: List[str], obj: Any) -> Optional[Any]:
-        """
-        Follows a property path through an object, bailing at the first None.
-        """
-        current = obj
-        for path_step in path:
-            if path_step in current:
-                current = current[path_step]
-            else:
-                return None
-        return current
-
-
-class DivaDownloader:
-    """
-    A downloader for DIVA videos.
-    """
-
-    def __init__(self, tmp_dir: TmpDir, organizer: Organizer, strategy: DivaDownloadStrategy):
-        self._tmp_dir = tmp_dir
-        self._organizer = organizer
-        self._strategy = strategy
-        self._session = requests.session()
-
-    def download_all(self, infos: List[DivaDownloadInfo]) -> None:
-        """
-        Download multiple files one after the other.
-        """
-        for info in infos:
-            self.download(info)
-
-    def download(self, info: DivaDownloadInfo) -> None:
-        """
-        Download a single file.
-        """
-        if not self._strategy(self._organizer, info):
-            self._organizer.mark(info.path)
-            return
-
-        with self._session.get(info.url, stream=True) as response:
-            if response.status_code == 200:
-                tmp_file = self._tmp_dir.new_path()
-                stream_to_path(response, tmp_file, info.path.name)
-                self._organizer.accept_file(tmp_file, info.path)
-            else:
-                PRETTY.warning(f"Could not download file, got response {response.status_code}")

PFERD/download_summary.py

@@ -1,75 +0,0 @@
-"""
-Provides a summary that keeps track of new modified or deleted files.
-"""
-from pathlib import Path
-from typing import List
-
-
-def _mergeNoDuplicate(first: List[Path], second: List[Path]) -> List[Path]:
-    tmp = list(set(first + second))
-    tmp.sort(key=lambda x: str(x.resolve()))
-    return tmp
-
-
-class DownloadSummary:
-    """
-    Keeps track of all new, modified or deleted files and provides a summary.
-    """
-
-    def __init__(self) -> None:
-        self._new_files: List[Path] = []
-        self._modified_files: List[Path] = []
-        self._deleted_files: List[Path] = []
-
-    @property
-    def new_files(self) -> List[Path]:
-        """
-        Returns all new files.
-        """
-        return self._new_files.copy()
-
-    @property
-    def modified_files(self) -> List[Path]:
-        """
-        Returns all modified files.
-        """
-        return self._modified_files.copy()
-
-    @property
-    def deleted_files(self) -> List[Path]:
-        """
-        Returns all deleted files.
-        """
-        return self._deleted_files.copy()
-
-    def merge(self, summary: 'DownloadSummary') -> None:
-        """
-        Merges ourselves with the passed summary. Modifies this object, but not the passed one.
-        """
-        self._new_files = _mergeNoDuplicate(self._new_files, summary.new_files)
-        self._modified_files = _mergeNoDuplicate(self._modified_files, summary.modified_files)
-        self._deleted_files = _mergeNoDuplicate(self._deleted_files, summary.deleted_files)
-
-    def add_deleted_file(self, path: Path) -> None:
-        """
-        Registers a file as deleted.
-        """
-        self._deleted_files.append(path)
-
-    def add_modified_file(self, path: Path) -> None:
-        """
-        Registers a file as changed.
-        """
-        self._modified_files.append(path)
-
-    def add_new_file(self, path: Path) -> None:
-        """
-        Registers a file as new.
-        """
-        self._new_files.append(path)
-
-    def has_updates(self) -> bool:
-        """
-        Returns whether this summary has any updates.
-        """
-        return bool(self._new_files or self._modified_files or self._deleted_files)

PFERD/downloaders.py

@@ -1,72 +0,0 @@
-"""
-General downloaders useful in many situations
-"""
-
-from dataclasses import dataclass, field
-from typing import Any, Dict, List, Optional
-
-import requests
-import requests.auth
-
-from .organizer import Organizer
-from .tmp_dir import TmpDir
-from .transform import Transformable
-from .utils import stream_to_path
-
-
-@dataclass
-class HttpDownloadInfo(Transformable):
-    """
-    This class describes a single file to be downloaded.
-    """
-
-    url: str
-    parameters: Dict[str, Any] = field(default_factory=dict)
-
-
-class HttpDownloader:
-    """A HTTP downloader that can handle HTTP basic auth."""
-
-    def __init__(
-            self,
-            tmp_dir: TmpDir,
-            organizer: Organizer,
-            username: Optional[str],
-            password: Optional[str],
-    ):
-        """Create a new http downloader."""
-        self._organizer = organizer
-        self._tmp_dir = tmp_dir
-        self._username = username
-        self._password = password
-        self._session = self._build_session()
-
-    def _build_session(self) -> requests.Session:
-        session = requests.Session()
-        if self._username and self._password:
-            session.auth = requests.auth.HTTPBasicAuth(
-                self._username, self._password
-            )
-        return session
-
-    def download_all(self, infos: List[HttpDownloadInfo]) -> None:
-        """
-        Download multiple files one after the other.
-        """
-
-        for info in infos:
-            self.download(info)
-
-    def download(self, info: HttpDownloadInfo) -> None:
-        """
-        Download a single file.
-        """
-
-        with self._session.get(info.url, params=info.parameters, stream=True) as response:
-            if response.status_code == 200:
-                tmp_file = self._tmp_dir.new_path()
-                stream_to_path(response, tmp_file, info.path.name)
-                self._organizer.accept_file(tmp_file, info.path)
-            else:
-                # TODO use proper exception
-                raise Exception(f"Could not download file, got response {response.status_code}")

PFERD/errors.py

@@ -1,57 +0,0 @@
-"""
-An error logging decorator.
-"""
-
-import logging
-from typing import Any, Callable, TypeVar, cast
-
-from rich.console import Console
-
-from .logging import PrettyLogger
-
-LOGGER = logging.getLogger(__name__)
-PRETTY = PrettyLogger(LOGGER)
-
-
-class FatalException(Exception):
-    """
-    A fatal exception occurred. Recovery is not possible.
-    """
-
-
-TFun = TypeVar('TFun', bound=Callable[..., Any])
-
-
-def swallow_and_print_errors(function: TFun) -> TFun:
-    """
-    Decorates a function, swallows all errors, logs them and returns none if one occurred.
-    """
-    def inner(*args: Any, **kwargs: Any) -> Any:
-        # pylint: disable=broad-except
-        try:
-            return function(*args, **kwargs)
-        except FatalException as error:
-            PRETTY.error(str(error))
-            return None
-        except Exception as error:
-            Console().print_exception()
-            return None
-    return cast(TFun, inner)
-
-
-def retry_on_io_exception(max_retries: int, message: str) -> Callable[[TFun], TFun]:
-    """
-    Decorates a function and retries it on any exception until the max retries count is hit.
-    """
-    def retry(function: TFun) -> TFun:
-        def inner(*args: Any, **kwargs: Any) -> Any:
-            for i in range(0, max_retries):
-                # pylint: disable=broad-except
-                try:
-                    return function(*args, **kwargs)
-                except IOError as error:
-                    PRETTY.warning(f"Error duing operation '{message}': {error}")
-                    PRETTY.warning(
-                        f"Retrying operation '{message}'. Remaining retries: {max_retries - 1 - i}")
-        return cast(TFun, inner)
-    return retry

PFERD/ilias/__init__.py

@@ -1,10 +0,0 @@
-"""
-Synchronizing files from ILIAS instances (https://www.ilias.de/).
-"""
-
-from .authenticators import IliasAuthenticator, KitShibbolethAuthenticator
-from .crawler import (IliasCrawler, IliasCrawlerEntry, IliasDirectoryFilter,
-                      IliasElementType)
-from .downloader import (IliasDownloader, IliasDownloadInfo,
-                         IliasDownloadStrategy, download_everything,
-                         download_modified_or_new)

PFERD/ilias/authenticators.py

@@ -1,138 +0,0 @@
-"""
-Authenticators that can obtain proper ILIAS session cookies.
-"""
-
-import abc
-import logging
-from typing import Optional
-
-import bs4
-import requests
-
-from ..authenticators import TfaAuthenticator, UserPassAuthenticator
-from ..utils import soupify
-
-LOGGER = logging.getLogger(__name__)
-
-
-class IliasAuthenticator(abc.ABC):
-    # pylint: disable=too-few-public-methods
-
-    """
-    An authenticator that logs an existing requests session into an ILIAS
-    account.
-    """
-
-    @abc.abstractmethod
-    def authenticate(self, sess: requests.Session) -> None:
-        """
-        Log a requests session into this authenticator's ILIAS account.
-        """
-
-
-class KitShibbolethAuthenticator(IliasAuthenticator):
-    # pylint: disable=too-few-public-methods
-
-    """
-    Authenticate via KIT's shibboleth system.
-    """
-
-    def __init__(self, authenticator: Optional[UserPassAuthenticator] = None) -> None:
-        if authenticator:
-            self._auth = authenticator
-        else:
-            self._auth = UserPassAuthenticator("KIT ILIAS Shibboleth")
-
-        self._tfa_auth = TfaAuthenticator("KIT ILIAS Shibboleth")
-
-    def authenticate(self, sess: requests.Session) -> None:
-        """
-        Performs the ILIAS Shibboleth authentication dance and saves the login
-        cookies it receieves.
-
-        This function should only be called whenever it is detected that you're
-        not logged in. The cookies obtained should be good for a few minutes,
-        maybe even an hour or two.
-        """
-
-        # Equivalent: Click on "Mit KIT-Account anmelden" button in
-        # https://ilias.studium.kit.edu/login.php
-        LOGGER.debug("Begin authentication process with ILIAS")
-        url = "https://ilias.studium.kit.edu/Shibboleth.sso/Login"
-        data = {
-            "sendLogin": "1",
-            "idp_selection": "https://idp.scc.kit.edu/idp/shibboleth",
-            "target": "/shib_login.php",
-            "home_organization_selection": "Mit KIT-Account anmelden",
-        }
-        soup = soupify(sess.post(url, data=data))
-
-        # Attempt to login using credentials, if necessary
-        while not self._login_successful(soup):
-            # Searching the form here so that this fails before asking for
-            # credentials rather than after asking.
-            form = soup.find("form", {"class": "full content", "method": "post"})
-            action = form["action"]
-
-            csrf_token = form.find("input", {"name": "csrf_token"})["value"]
-
-            # Equivalent: Enter credentials in
-            # https://idp.scc.kit.edu/idp/profile/SAML2/Redirect/SSO
-            LOGGER.debug("Attempt to log in to Shibboleth using credentials")
-            url = "https://idp.scc.kit.edu" + action
-            data = {
-                "_eventId_proceed": "",
-                "j_username": self._auth.username,
-                "j_password": self._auth.password,
-                "csrf_token": csrf_token
-            }
-            soup = soupify(sess.post(url, data=data))
-
-            if self._tfa_required(soup):
-                soup = self._authenticate_tfa(sess, soup)
-
-            if not self._login_successful(soup):
-                print("Incorrect credentials.")
-                self._auth.invalidate_credentials()
-
-        # Equivalent: Being redirected via JS automatically
-        # (or clicking "Continue" if you have JS disabled)
-        LOGGER.debug("Redirect back to ILIAS with login information")
-        relay_state = soup.find("input", {"name": "RelayState"})
-        saml_response = soup.find("input", {"name": "SAMLResponse"})
-        url = "https://ilias.studium.kit.edu/Shibboleth.sso/SAML2/POST"
-        data = {  # using the info obtained in the while loop above
-            "RelayState": relay_state["value"],
-            "SAMLResponse": saml_response["value"],
-        }
-        sess.post(url, data=data)
-
-    def _authenticate_tfa(
-            self,
-            session: requests.Session,
-            soup: bs4.BeautifulSoup
-    ) -> bs4.BeautifulSoup:
-        # Searching the form here so that this fails before asking for
-        # credentials rather than after asking.
-        form = soup.find("form", {"method": "post"})
-        action = form["action"]
-
-        # Equivalent: Enter token in
-        # https://idp.scc.kit.edu/idp/profile/SAML2/Redirect/SSO
-        LOGGER.debug("Attempt to log in to Shibboleth with TFA token")
-        url = "https://idp.scc.kit.edu" + action
-        data = {
-            "_eventId_proceed": "",
-            "j_tokenNumber": self._tfa_auth.get_token()
-        }
-        return soupify(session.post(url, data=data))
-
-    @staticmethod
-    def _login_successful(soup: bs4.BeautifulSoup) -> bool:
-        relay_state = soup.find("input", {"name": "RelayState"})
-        saml_response = soup.find("input", {"name": "SAMLResponse"})
-        return relay_state is not None and saml_response is not None
-
-    @staticmethod
-    def _tfa_required(soup: bs4.BeautifulSoup) -> bool:
-        return soup.find(id="j_tokenNumber") is not None

PFERD/ilias/crawler.py

@@ -1,684 +0,0 @@
-"""
-Contains an ILIAS crawler alongside helper functions.
-"""
-
-import datetime
-import json
-import logging
-import re
-from enum import Enum
-from pathlib import Path
-from typing import Any, Callable, Dict, List, Optional, Union
-from urllib.parse import (parse_qs, urlencode, urljoin, urlparse, urlsplit,
-                          urlunsplit)
-
-import bs4
-import requests
-
-from ..errors import FatalException, retry_on_io_exception
-from ..logging import PrettyLogger
-from ..utils import soupify
-from .authenticators import IliasAuthenticator
-from .date_demangler import demangle_date
-from .downloader import IliasDownloadInfo
-
-LOGGER = logging.getLogger(__name__)
-PRETTY = PrettyLogger(LOGGER)
-
-
-def _sanitize_path_name(name: str) -> str:
-    return name.replace("/", "-").replace("\\", "-")
-
-
-class IliasElementType(Enum):
-    """
-    The type of an ilias element.
-    """
-    REGULAR_FOLDER = "REGULAR_FOLDER"
-    VIDEO_FOLDER = "VIDEO_FOLDER"
-    EXERCISE_FOLDER = "EXERCISE_FOLDER"
-    REGULAR_FILE = "REGULAR_FILE"
-    VIDEO_FILE = "VIDEO_FILE"
-    FORUM = "FORUM"
-    MEETING = "MEETING"
-    EXTERNAL_LINK = "EXTERNAL_LINK"
-
-    def is_folder(self) -> bool:
-        """
-        Returns whether this type is some kind of folder.
-        """
-        return "FOLDER" in str(self.name)
-
-
-IliasDirectoryFilter = Callable[[Path, IliasElementType], bool]
-
-
-class IliasCrawlerEntry:
-    # pylint: disable=too-few-public-methods
-    """
-    An ILIAS crawler entry used internally to find, catalogue and recursively crawl elements.
-    """
-
-    def __init__(
-            self,
-            path: Path,
-            url: Union[str, Callable[[], Optional[str]]],
-            entry_type: IliasElementType,
-            modification_date: Optional[datetime.datetime]
-    ):
-        self.path = path
-        if isinstance(url, str):
-            str_url = url
-            self.url: Callable[[], Optional[str]] = lambda: str_url
-        else:
-            self.url = url
-        self.entry_type = entry_type
-        self.modification_date = modification_date
-
-    def to_download_info(self) -> Optional[IliasDownloadInfo]:
-        """
-        Converts this crawler entry to an IliasDownloadInfo, if possible.
-        This method will only succeed for *File* types.
-        """
-        if self.entry_type in [IliasElementType.REGULAR_FILE, IliasElementType.VIDEO_FILE]:
-            return IliasDownloadInfo(self.path, self.url, self.modification_date)
-        return None
-
-
-class IliasCrawler:
-    # pylint: disable=too-few-public-methods
-
-    """
-    A crawler for ILIAS.
-    """
-
-    # pylint: disable=too-many-arguments
-    def __init__(
-            self,
-            base_url: str,
-            session: requests.Session,
-            authenticator: IliasAuthenticator,
-            dir_filter: IliasDirectoryFilter
-    ):
-        """
-        Create a new ILIAS crawler.
-        """
-
-        self._base_url = base_url
-        self._session = session
-        self._authenticator = authenticator
-        self.dir_filter = dir_filter
-
-    @staticmethod
-    def _url_set_query_param(url: str, param: str, value: str) -> str:
-        """
-        Set a query parameter in an url, overwriting existing ones with the same name.
-        """
-        scheme, netloc, path, query, fragment = urlsplit(url)
-        query_parameters = parse_qs(query)
-        query_parameters[param] = [value]
-        new_query_string = urlencode(query_parameters, doseq=True)
-
-        return urlunsplit((scheme, netloc, path, new_query_string, fragment))
-
-    def recursive_crawl_url(self, url: str) -> List[IliasDownloadInfo]:
-        """
-        Crawls a given url *and all reachable elements in it*.
-
-        Args:
-            url {str} -- the *full* url to crawl
-        """
-        start_entries: List[IliasCrawlerEntry] = self._crawl_folder(Path(""), url)
-        return self._iterate_entries_to_download_infos(start_entries)
-
-    def crawl_course(self, course_id: str) -> List[IliasDownloadInfo]:
-        """
-        Starts the crawl process for a course, yielding a list of elements to (potentially)
-        download.
-
-        Arguments:
-            course_id {str} -- the course id
-
-        Raises:
-            FatalException: if an unrecoverable error occurs or the course id is not valid
-        """
-        # Start crawling at the given course
-        root_url = self._url_set_query_param(
-            self._base_url + "/goto.php", "target", f"crs_{course_id}"
-        )
-
-        if not self._is_course_id_valid(root_url, course_id):
-            raise FatalException(
-                "Invalid course id? I didn't find anything looking like a course!"
-            )
-
-        # And treat it as a folder
-        entries: List[IliasCrawlerEntry] = self._crawl_folder(Path(""), root_url)
-        return self._iterate_entries_to_download_infos(entries)
-
-    def _is_course_id_valid(self, root_url: str, course_id: str) -> bool:
-        response: requests.Response = self._session.get(root_url)
-        # We were redirected ==> Non-existant ID
-        if course_id not in response.url:
-            return False
-
-        link_element: bs4.Tag = self._get_page(root_url, {}).find(id="current_perma_link")
-        if not link_element:
-            return False
-        # It wasn't a course but a category list, forum, etc.
-        return "crs_" in link_element.get("value")
-
-    def find_course_name(self, course_id: str) -> Optional[str]:
-        """
-        Returns the name of a given course. None if it is not a valid course
-        or it could not be found.
-        """
-        course_url = self._url_set_query_param(
-            self._base_url + "/goto.php", "target", f"crs_{course_id}"
-        )
-        return self.find_element_name(course_url)
-
-    def find_element_name(self, url: str) -> Optional[str]:
-        """
-        Returns the name of the element at the given URL, if it can find one.
-        """
-        focus_element: bs4.Tag = self._get_page(url, {}).find(id="il_mhead_t_focus")
-        if not focus_element:
-            return None
-        return focus_element.text
-
-    def crawl_personal_desktop(self) -> List[IliasDownloadInfo]:
-        """
-        Crawls the ILIAS personal desktop (and every subelements that can be reached from there).
-
-        Raises:
-            FatalException: if an unrecoverable error occurs
-        """
-        entries: List[IliasCrawlerEntry] = self._crawl_folder(
-            Path(""), self._base_url + "?baseClass=ilPersonalDesktopGUI"
-        )
-        return self._iterate_entries_to_download_infos(entries)
-
-    def _iterate_entries_to_download_infos(
-            self,
-            entries: List[IliasCrawlerEntry]
-    ) -> List[IliasDownloadInfo]:
-        result: List[IliasDownloadInfo] = []
-        entries_to_process: List[IliasCrawlerEntry] = entries.copy()
-        while len(entries_to_process) > 0:
-            entry = entries_to_process.pop()
-
-            if entry.entry_type == IliasElementType.EXTERNAL_LINK:
-                PRETTY.not_searching(entry.path, "external link")
-                continue
-            if entry.entry_type == IliasElementType.FORUM:
-                PRETTY.not_searching(entry.path, "forum")
-                continue
-
-            if entry.entry_type.is_folder() and not self.dir_filter(entry.path, entry.entry_type):
-                PRETTY.not_searching(entry.path, "user filter")
-                continue
-
-            download_info = entry.to_download_info()
-            if download_info is not None:
-                result.append(download_info)
-                continue
-
-            url = entry.url()
-
-            if url is None:
-                PRETTY.warning(f"Could not find url for {str(entry.path)!r}, skipping it")
-                continue
-
-            PRETTY.searching(entry.path)
-
-            if entry.entry_type == IliasElementType.EXERCISE_FOLDER:
-                entries_to_process += self._crawl_exercises(entry.path, url)
-                continue
-            if entry.entry_type == IliasElementType.REGULAR_FOLDER:
-                entries_to_process += self._crawl_folder(entry.path, url)
-                continue
-            if entry.entry_type == IliasElementType.VIDEO_FOLDER:
-                entries_to_process += self._crawl_video_directory(entry.path, url)
-                continue
-
-            PRETTY.warning(f"Unknown type: {entry.entry_type}!")
-
-        return result
-
-    def _crawl_folder(self, folder_path: Path, url: str) -> List[IliasCrawlerEntry]:
-        """
-        Crawl all files in a folder-like element.
-        """
-        soup = self._get_page(url, {})
-
-        if soup.find(id="headerimage"):
-            element: bs4.Tag = soup.find(id="headerimage")
-            if "opencast" in element.attrs["src"].lower():
-                PRETTY.warning(f"Switched to crawling a video at {folder_path}")
-                if not self.dir_filter(folder_path, IliasElementType.VIDEO_FOLDER):
-                    PRETTY.not_searching(folder_path, "user filter")
-                    return []
-                return self._crawl_video_directory(folder_path, url)
-
-        result: List[IliasCrawlerEntry] = []
-
-        # Fetch all links and throw them to the general interpreter
-        links: List[bs4.Tag] = soup.select("a.il_ContainerItemTitle")
-        for link in links:
-            abs_url = self._abs_url_from_link(link)
-            element_path = Path(folder_path, _sanitize_path_name(link.getText().strip()))
-            element_type = self._find_type_from_link(element_path, link, abs_url)
-
-            if element_type == IliasElementType.REGULAR_FILE:
-                result += self._crawl_file(folder_path, link, abs_url)
-            elif element_type == IliasElementType.MEETING:
-                meeting_name = str(element_path.name)
-                date_portion_str = meeting_name.split(" - ")[0]
-                date_portion = demangle_date(date_portion_str)
-
-                if not date_portion:
-                    result += [IliasCrawlerEntry(element_path, abs_url, element_type, None)]
-                    continue
-
-                rest_of_name = meeting_name
-                if rest_of_name.startswith(date_portion_str):
-                    rest_of_name = rest_of_name[len(date_portion_str):]
-
-                new_name = datetime.datetime.strftime(date_portion, "%Y-%m-%d, %H:%M") \
-                    + rest_of_name
-                new_path = Path(folder_path, _sanitize_path_name(new_name))
-                result += [
-                    IliasCrawlerEntry(new_path, abs_url, IliasElementType.REGULAR_FOLDER, None)
-                ]
-            elif element_type is not None:
-                result += [IliasCrawlerEntry(element_path, abs_url, element_type, None)]
-            else:
-                PRETTY.warning(f"Found element without a type at {str(element_path)!r}")
-
-        return result
-
-    def _abs_url_from_link(self, link_tag: bs4.Tag) -> str:
-        """
-        Create an absolute url from an <a> tag.
-        """
-        return urljoin(self._base_url, link_tag.get("href"))
-
-    @staticmethod
-    def _find_type_from_link(
-            path: Path,
-            link_element: bs4.Tag,
-            url: str
-    ) -> Optional[IliasElementType]:
-        """
-        Decides which sub crawler to use for a given top level element.
-        """
-        parsed_url = urlparse(url)
-        LOGGER.debug("Parsed url: %r", parsed_url)
-
-        # file URLs contain "target=file"
-        if "target=file_" in parsed_url.query:
-            return IliasElementType.REGULAR_FILE
-
-        # Skip forums
-        if "cmd=showThreads" in parsed_url.query:
-            return IliasElementType.FORUM
-
-        # Everything with a ref_id can *probably* be opened to reveal nested things
-        # video groups, directories, exercises, etc
-        if "ref_id=" in parsed_url.query:
-            return IliasCrawler._find_type_from_folder_like(link_element, url)
-
-        PRETTY.warning(
-            "Got unknown element type in switch. I am not sure what horror I found on the"
-            f" ILIAS page. The element was at {str(path)!r} and it is {link_element!r})"
-        )
-        return None
-
-    @staticmethod
-    def _find_type_from_folder_like(link_element: bs4.Tag, url: str) -> Optional[IliasElementType]:
-        """
-        Try crawling something that looks like a folder.
-        """
-        # pylint: disable=too-many-return-statements
-
-        found_parent: Optional[bs4.Tag] = None
-
-        # We look for the outer div of our inner link, to find information around it
-        # (mostly the icon)
-        for parent in link_element.parents:
-            if "ilContainerListItemOuter" in parent["class"]:
-                found_parent = parent
-                break
-
-        if found_parent is None:
-            PRETTY.warning(f"Could not find element icon for {url!r}")
-            return None
-
-        # Find the small descriptive icon to figure out the type
-        img_tag: Optional[bs4.Tag] = found_parent.select_one("img.ilListItemIcon")
-
-        if img_tag is None:
-            PRETTY.warning(f"Could not find image tag for {url!r}")
-            return None
-
-        if "opencast" in str(img_tag["alt"]).lower():
-            return IliasElementType.VIDEO_FOLDER
-
-        if str(img_tag["src"]).endswith("icon_exc.svg"):
-            return IliasElementType.EXERCISE_FOLDER
-
-        if str(img_tag["src"]).endswith("icon_webr.svg"):
-            return IliasElementType.EXTERNAL_LINK
-
-        if str(img_tag["src"]).endswith("frm.svg"):
-            return IliasElementType.FORUM
-
-        if str(img_tag["src"]).endswith("sess.svg"):
-            return IliasElementType.MEETING
-
-        return IliasElementType.REGULAR_FOLDER
-
-    @staticmethod
-    def _crawl_file(path: Path, link_element: bs4.Tag, url: str) -> List[IliasCrawlerEntry]:
-        """
-        Crawls a file.
-        """
-        # Files have a list of properties (type, modification date, size, etc.)
-        # In a series of divs.
-        # Find the parent containing all those divs, so we can filter our what we need
-        properties_parent: bs4.Tag = link_element.findParent(
-            "div", {"class": lambda x: "il_ContainerListItem" in x}
-        ).select_one(".il_ItemProperties")
-        # The first one is always the filetype
-        file_type = properties_parent.select_one("span.il_ItemProperty").getText().strip()
-
-        # The rest does not have a stable order. Grab the whole text and reg-ex the date
-        # out of it
-        all_properties_text = properties_parent.getText().strip()
-        modification_date_match = re.search(
-            r"(((\d+\. \w+ \d+)|(Gestern|Yesterday)|(Heute|Today)|(Morgen|Tomorrow)), \d+:\d+)",
-            all_properties_text
-        )
-        if modification_date_match is None:
-            modification_date = None
-            PRETTY.warning(f"Could not extract start date from {all_properties_text!r}")
-        else:
-            modification_date_str = modification_date_match.group(1)
-            modification_date = demangle_date(modification_date_str)
-
-        # Grab the name from the link text
-        name = _sanitize_path_name(link_element.getText())
-        full_path = Path(path, name + "." + file_type)
-
-        return [
-            IliasCrawlerEntry(full_path, url, IliasElementType.REGULAR_FILE, modification_date)
-        ]
-
-    def _crawl_video_directory(self, video_dir_path: Path, url: str) -> List[IliasCrawlerEntry]:
-        """
-        Crawl the video overview site.
-        """
-        initial_soup = self._get_page(url, {})
-
-        # The page is actually emtpy but contains a much needed token in the link below.
-        # That token can be used to fetch the *actual* video listing
-        content_link: bs4.Tag = initial_soup.select_one("#tab_series a")
-        # Fetch the actual video listing. The given parameters return all videos (max 800)
-        # in a standalone html page
-        video_list_soup = self._get_page(
-            self._abs_url_from_link(content_link),
-            {"limit": 800, "cmd": "asyncGetTableGUI", "cmdMode": "asynch"}
-        )
-
-        # If we find a page selected, we probably need to respect pagination
-        if self._is_paginated_video_page(video_list_soup):
-            second_stage_url = self._abs_url_from_link(content_link)
-
-            return self._crawl_paginated_video_directory(
-                video_dir_path, video_list_soup, second_stage_url
-            )
-
-        return self._crawl_video_directory_second_stage(video_dir_path, video_list_soup)
-
-    @staticmethod
-    def _is_paginated_video_page(soup: bs4.BeautifulSoup) -> bool:
-        return soup.find(id=re.compile(r"tab_page_sel.+")) is not None
-
-    def _crawl_paginated_video_directory(
-            self,
-            video_dir_path: Path,
-            paged_video_list_soup: bs4.BeautifulSoup,
-            second_stage_url: str
-    ) -> List[IliasCrawlerEntry]:
-        LOGGER.info("Found paginated video page, trying 800 elements")
-
-        # Try to find the table id. This can be used to build the query parameter indicating
-        # you want 800 elements
-
-        table_element: bs4.Tag = paged_video_list_soup.find(
-            name="table", id=re.compile(r"tbl_xoct_.+")
-        )
-        if table_element is None:
-            PRETTY.warning(
-                "Could not increase elements per page (table not found)."
-                " Some might not be crawled!"
-            )
-            return self._crawl_video_directory_second_stage(video_dir_path, paged_video_list_soup)
-
-        match = re.match(r"tbl_xoct_(.+)", table_element.attrs["id"])
-        if match is None:
-            PRETTY.warning(
-                "Could not increase elements per page (table id not found)."
-                " Some might not be crawled!"
-            )
-            return self._crawl_video_directory_second_stage(video_dir_path, paged_video_list_soup)
-        table_id = match.group(1)
-
-        extended_video_page = self._get_page(
-            second_stage_url,
-            {f"tbl_xoct_{table_id}_trows": 800, "cmd": "asyncGetTableGUI", "cmdMode": "asynch"}
-        )
-
-        if self._is_paginated_video_page(extended_video_page):
-            PRETTY.warning(
-                "800 elements do not seem to be enough (or I failed to fetch that many)."
-                " I will miss elements."
-            )
-
-        return self._crawl_video_directory_second_stage(video_dir_path, extended_video_page)
-
-    def _crawl_video_directory_second_stage(
-            self,
-            video_dir_path: Path,
-            video_list_soup: bs4.BeautifulSoup
-    ) -> List[IliasCrawlerEntry]:
-        """
-        Crawls the "second stage" video page. This page contains the actual video urls.
-        """
-        direct_download_links: List[bs4.Tag] = video_list_soup.findAll(
-            name="a", text=re.compile(r"\s*Download\s*")
-        )
-
-        # Video start links are marked with an "Abspielen" link
-        video_links: List[bs4.Tag] = video_list_soup.findAll(
-            name="a", text=re.compile(r"\s*Abspielen\s*")
-        )
-
-        results: List[IliasCrawlerEntry] = []
-
-        # We can download everything directly!
-        # FIXME: Sadly the download button is currently broken, so never do that
-        if False and len(direct_download_links) == len(video_links):
-            for link in direct_download_links:
-                results += self._crawl_single_video(video_dir_path, link, True)
-        else:
-            for link in video_links:
-                results += self._crawl_single_video(video_dir_path, link, False)
-
-        return results
-
-    def _crawl_single_video(
-            self,
-            parent_path: Path,
-            link: bs4.Tag,
-            direct_download: bool
-    ) -> List[IliasCrawlerEntry]:
-        """
-        Crawl a single video based on its "Abspielen" link from the video listing.
-        """
-        # The link is part of a table with multiple columns, describing metadata.
-        # 6th child (1 indexed) is the modification time string
-        modification_string = link.parent.parent.parent.select_one(
-            "td.std:nth-child(6)"
-        ).getText().strip()
-        modification_time = datetime.datetime.strptime(modification_string, "%d.%m.%Y - %H:%M")
-
-        title = link.parent.parent.parent.select_one(
-            "td.std:nth-child(3)"
-        ).getText().strip()
-        title += ".mp4"
-
-        video_path: Path = Path(parent_path, _sanitize_path_name(title))
-
-        video_url = self._abs_url_from_link(link)
-
-        # The video had a direct download button we can use instead
-        if direct_download:
-            LOGGER.debug("Using direct download for video %r", str(video_path))
-            return [IliasCrawlerEntry(
-                video_path, video_url, IliasElementType.VIDEO_FILE, modification_time
-            )]
-
-        return [IliasCrawlerEntry(
-            video_path,
-            self._crawl_video_url_from_play_link(video_url),
-            IliasElementType.VIDEO_FILE,
-            modification_time
-        )]
-
-    def _crawl_video_url_from_play_link(self, play_url: str) -> Callable[[], Optional[str]]:
-        def inner() -> Optional[str]:
-            # Fetch the actual video page. This is a small wrapper page initializing a javscript
-            # player. Sadly we can not execute that JS. The actual video stream url is nowhere
-            # on the page, but defined in a JS object inside a script tag, passed to the player
-            # library.
-            # We do the impossible and RegEx the stream JSON object out of the page's HTML source
-            video_page_soup = soupify(self._session.get(play_url))
-            regex: re.Pattern = re.compile(
-                r"({\"streams\"[\s\S]+?),\s*{\"paella_config_file", re.IGNORECASE
-            )
-            json_match = regex.search(str(video_page_soup))
-
-            if json_match is None:
-                PRETTY.warning(f"Could not find json stream info for {play_url!r}")
-                return None
-            json_str = json_match.group(1)
-
-            # parse it
-            json_object = json.loads(json_str)
-            # and fetch the video url!
-            video_url = json_object["streams"][0]["sources"]["mp4"][0]["src"]
-            return video_url
-        return inner
-
-    def _crawl_exercises(self, element_path: Path, url: str) -> List[IliasCrawlerEntry]:
-        """
-        Crawl files offered for download in exercises.
-        """
-        soup = self._get_page(url, {})
-
-        results: List[IliasCrawlerEntry] = []
-
-        # Each assignment is in an accordion container
-        assignment_containers: List[bs4.Tag] = soup.select(".il_VAccordionInnerContainer")
-
-        for container in assignment_containers:
-            # Fetch the container name out of the header to use it in the path
-            container_name = container.select_one(".ilAssignmentHeader").getText().strip()
-            # Find all download links in the container (this will contain all the files)
-            files: List[bs4.Tag] = container.findAll(
-                name="a",
-                # download links contain the given command class
-                attrs={"href": lambda x: x and "cmdClass=ilexsubmissiongui" in x},
-                text="Download"
-            )
-
-            LOGGER.debug("Found exercise container %r", container_name)
-
-            # Grab each file as you now have the link
-            for file_link in files:
-                # Two divs, side by side. Left is the name, right is the link ==> get left
-                # sibling
-                file_name = file_link.parent.findPrevious(name="div").getText().strip()
-                file_name = _sanitize_path_name(file_name)
-                url = self._abs_url_from_link(file_link)
-
-                LOGGER.debug("Found file %r at %r", file_name, url)
-
-                results.append(IliasCrawlerEntry(
-                    Path(element_path, container_name, file_name),
-                    url,
-                    IliasElementType.REGULAR_FILE,
-                    None  # We do not have any timestamp
-                ))
-
-        return results
-
-    @retry_on_io_exception(3, "fetching webpage")
-    def _get_page(self, url: str, params: Dict[str, Any],
-                  retry_count: int = 0) -> bs4.BeautifulSoup:
-        """
-        Fetches a page from ILIAS, authenticating when needed.
-        """
-
-        if retry_count >= 4:
-            raise FatalException("Could not get a proper page after 4 tries. "
-                                 "Maybe your URL is wrong, authentication fails continuously, "
-                                 "your ILIAS connection is spotty or ILIAS is not well.")
-
-        LOGGER.debug("Fetching %r", url)
-
-        response = self._session.get(url, params=params)
-        content_type = response.headers["content-type"]
-
-        if not content_type.startswith("text/html"):
-            raise FatalException(
-                f"Invalid content type {content_type} when crawling ilias page"
-                " {url!r} with {params!r}"
-            )
-
-        soup = soupify(response)
-
-        if self._is_logged_in(soup):
-            return soup
-
-        LOGGER.info("Not authenticated, changing that...")
-
-        self._authenticator.authenticate(self._session)
-
-        return self._get_page(url, params, retry_count + 1)
-
-    @staticmethod
-    def _is_logged_in(soup: bs4.BeautifulSoup) -> bool:
-        # Normal ILIAS pages
-        userlog = soup.find("li", {"id": "userlog"})
-        if userlog is not None:
-            LOGGER.debug("Auth: Found #userlog")
-            return True
-        # Video listing embeds do not have complete ILIAS html. Try to match them by
-        # their video listing table
-        video_table = soup.find(
-            recursive=True,
-            name="table",
-            attrs={"id": lambda x: x is not None and x.startswith("tbl_xoct")}
-        )
-        if video_table is not None:
-            LOGGER.debug("Auth: Found #tbl_xoct.+")
-            return True
-        # The individual video player wrapper page has nothing of the above.
-        # Match it by its playerContainer.
-        if soup.select_one("#playerContainer") is not None:
-            LOGGER.debug("Auth: Found #playerContainer")
-            return True
-        return False

PFERD/ilias/date_demangler.py

@@ -1,51 +0,0 @@
-"""
-Helper methods to demangle an ILIAS date.
-"""
-
-import datetime
-import locale
-import logging
-import re
-from typing import Optional
-
-from ..logging import PrettyLogger
-
-LOGGER = logging.getLogger(__name__)
-PRETTY = PrettyLogger(LOGGER)
-
-
-def demangle_date(date: str) -> Optional[datetime.datetime]:
-    """
-    Demangle a given date in one of the following formats:
-    "Gestern, HH:MM"
-    "Heute, HH:MM"
-    "Morgen, HH:MM"
-    "dd. mon yyyy, HH:MM
-    """
-    saved = locale.setlocale(locale.LC_ALL)
-    try:
-        try:
-            locale.setlocale(locale.LC_ALL, 'de_DE.UTF-8')
-        except locale.Error:
-            PRETTY.warning(
-                "Could not set language to german. Assuming you use english everywhere."
-            )
-
-        date = re.sub(r"\s+", " ", date)
-        date = re.sub("Gestern|Yesterday", _yesterday().strftime("%d. %b %Y"), date, re.I)
-        date = re.sub("Heute|Today", datetime.date.today().strftime("%d. %b %Y"), date, re.I)
-        date = re.sub("Morgen|Tomorrow", _tomorrow().strftime("%d. %b %Y"), date, re.I)
-        return datetime.datetime.strptime(date, "%d. %b %Y, %H:%M")
-    except ValueError:
-        PRETTY.warning(f"Could not parse date {date!r}")
-        return None
-    finally:
-        locale.setlocale(locale.LC_ALL, saved)
-
-
-def _yesterday() -> datetime.date:
-    return datetime.date.today() - datetime.timedelta(days=1)
-
-
-def _tomorrow() -> datetime.date:
-    return datetime.date.today() + datetime.timedelta(days=1)

PFERD/ilias/downloader.py

@@ -1,173 +0,0 @@
-"""Contains a downloader for ILIAS."""
-
-import datetime
-import logging
-import math
-import os
-from pathlib import Path, PurePath
-from typing import Callable, List, Optional, Union
-
-import bs4
-import requests
-
-from ..errors import retry_on_io_exception
-from ..logging import PrettyLogger
-from ..organizer import Organizer
-from ..tmp_dir import TmpDir
-from ..transform import Transformable
-from ..utils import soupify, stream_to_path
-from .authenticators import IliasAuthenticator
-
-LOGGER = logging.getLogger(__name__)
-PRETTY = PrettyLogger(LOGGER)
-
-
-class ContentTypeException(Exception):
-    """Thrown when the content type of the ilias element can not be handled."""
-
-
-class IliasDownloadInfo(Transformable):
-    """
-    This class describes a single file to be downloaded.
-    """
-
-    def __init__(
-            self,
-            path: PurePath,
-            url: Union[str, Callable[[], Optional[str]]],
-            modifcation_date: Optional[datetime.datetime]
-    ):
-        super().__init__(path)
-        if isinstance(url, str):
-            string_url = url
-            self.url: Callable[[], Optional[str]] = lambda: string_url
-        else:
-            self.url = url
-        self.modification_date = modifcation_date
-
-
-IliasDownloadStrategy = Callable[[Organizer, IliasDownloadInfo], bool]
-
-
-def download_everything(organizer: Organizer, info: IliasDownloadInfo) -> bool:
-    # pylint: disable=unused-argument
-    """
-    Accepts everything.
-    """
-    return True
-
-
-def download_modified_or_new(organizer: Organizer, info: IliasDownloadInfo) -> bool:
-    """
-    Accepts new files or files with a more recent modification date.
-    """
-    resolved_file = organizer.resolve(info.path)
-    if not resolved_file.exists() or info.modification_date is None:
-        return True
-    resolved_mod_time_seconds = resolved_file.stat().st_mtime
-
-    # Download if the info is newer
-    if info.modification_date.timestamp() > resolved_mod_time_seconds:
-        return True
-
-    PRETTY.ignored_file(info.path, "local file has newer or equal modification time")
-    return False
-
-
-class IliasDownloader:
-    # pylint: disable=too-many-arguments
-    """A downloader for ILIAS."""
-
-    def __init__(
-            self,
-            tmp_dir: TmpDir,
-            organizer: Organizer,
-            session: requests.Session,
-            authenticator: IliasAuthenticator,
-            strategy: IliasDownloadStrategy,
-            timeout: int = 5
-    ):
-        """
-        Create a new IliasDownloader.
-
-        The timeout applies to the download request only, as bwcloud uses IPv6
-        and requests has a problem with that: https://github.com/psf/requests/issues/5522
-        """
-
-        self._tmp_dir = tmp_dir
-        self._organizer = organizer
-        self._session = session
-        self._authenticator = authenticator
-        self._strategy = strategy
-        self._timeout = timeout
-
-    def download_all(self, infos: List[IliasDownloadInfo]) -> None:
-        """
-        Download multiple files one after the other.
-        """
-
-        for info in infos:
-            self.download(info)
-
-    def download(self, info: IliasDownloadInfo) -> None:
-        """
-        Download a file from ILIAS.
-
-        Retries authentication until eternity if it could not fetch the file.
-        """
-
-        LOGGER.debug("Downloading %r", info)
-
-        if not self._strategy(self._organizer, info):
-            self._organizer.mark(info.path)
-            return
-
-        tmp_file = self._tmp_dir.new_path()
-
-        @retry_on_io_exception(3, "downloading file")
-        def download_impl() -> bool:
-            if not self._try_download(info, tmp_file):
-                LOGGER.info("Re-Authenticating due to download failure: %r", info)
-                self._authenticator.authenticate(self._session)
-                raise IOError("Scheduled retry")
-            else:
-                return True
-
-        if not download_impl():
-            PRETTY.error(f"Download of file {info.path} failed too often! Skipping it...")
-            return
-
-        dst_path = self._organizer.accept_file(tmp_file, info.path)
-        if dst_path and info.modification_date:
-            os.utime(
-                dst_path,
-                times=(
-                    math.ceil(info.modification_date.timestamp()),
-                    math.ceil(info.modification_date.timestamp())
-                )
-            )
-
-    def _try_download(self, info: IliasDownloadInfo, target: Path) -> bool:
-        url = info.url()
-        if url is None:
-            PRETTY.warning(f"Could not download {str(info.path)!r} as I got no URL :/")
-            return True
-
-        with self._session.get(url, stream=True, timeout=self._timeout) as response:
-            content_type = response.headers["content-type"]
-            has_content_disposition = "content-disposition" in response.headers
-
-            if content_type.startswith("text/html") and not has_content_disposition:
-                if self._is_logged_in(soupify(response)):
-                    raise ContentTypeException("Attempting to download a web page, not a file")
-
-                return False
-
-            # Yay, we got the file :)
-            stream_to_path(response, target, info.path.name)
-            return True
-
-    @staticmethod
-    def _is_logged_in(soup: bs4.BeautifulSoup) -> bool:
-        userlog = soup.find("li", {"id": "userlog"})
-        return userlog is not None

PFERD/ipd.py

@@ -1,154 +0,0 @@
-"""
-Utility functions and a scraper/downloader for the IPD pages.
-"""
-import datetime
-import logging
-import math
-import os
-from dataclasses import dataclass
-from pathlib import Path
-from typing import Callable, List, Optional
-from urllib.parse import urljoin
-
-import bs4
-import requests
-
-from PFERD.errors import FatalException
-from PFERD.utils import soupify
-
-from .logging import PrettyLogger
-from .organizer import Organizer
-from .tmp_dir import TmpDir
-from .transform import Transformable
-from .utils import stream_to_path
-
-LOGGER = logging.getLogger(__name__)
-PRETTY = PrettyLogger(LOGGER)
-
-
-@dataclass
-class IpdDownloadInfo(Transformable):
-    """
-    Information about an ipd entry.
-    """
-    url: str
-    modification_date: Optional[datetime.datetime]
-
-
-IpdDownloadStrategy = Callable[[Organizer, IpdDownloadInfo], bool]
-
-
-def ipd_download_new_or_modified(organizer: Organizer, info: IpdDownloadInfo) -> bool:
-    """
-    Accepts new files or files with a more recent modification date.
-    """
-    resolved_file = organizer.resolve(info.path)
-    if not resolved_file.exists():
-        return True
-    if not info.modification_date:
-        PRETTY.ignored_file(info.path, "could not find modification time, file exists")
-        return False
-
-    resolved_mod_time_seconds = resolved_file.stat().st_mtime
-
-    # Download if the info is newer
-    if info.modification_date.timestamp() > resolved_mod_time_seconds:
-        return True
-
-    PRETTY.ignored_file(info.path, "local file has newer or equal modification time")
-    return False
-
-
-class IpdCrawler:
-    # pylint: disable=too-few-public-methods
-    """
-    A crawler for IPD pages.
-    """
-
-    def __init__(self, base_url: str):
-        self._base_url = base_url
-
-    def _abs_url_from_link(self, link_tag: bs4.Tag) -> str:
-        """
-        Create an absolute url from an <a> tag.
-        """
-        return urljoin(self._base_url, link_tag.get("href"))
-
-    def crawl(self) -> List[IpdDownloadInfo]:
-        """
-        Crawls the playlist given in the constructor.
-        """
-        page = soupify(requests.get(self._base_url))
-
-        items: List[IpdDownloadInfo] = []
-
-        def is_relevant_url(x: str) -> bool:
-            return x.endswith(".pdf") or x.endswith(".c") or x.endswith(".java") or x.endswith(".zip")
-
-        for link in page.findAll(name="a", attrs={"href": lambda x: x and is_relevant_url(x)}):
-            href: str = link.attrs.get("href")
-            name = href.split("/")[-1]
-
-            modification_date: Optional[datetime.datetime] = None
-            try:
-                enclosing_row: bs4.Tag = link.findParent(name="tr")
-                if enclosing_row:
-                    date_text = enclosing_row.find(name="td").text
-                    modification_date = datetime.datetime.strptime(date_text, "%d.%m.%Y")
-            except ValueError:
-                modification_date = None
-
-            items.append(IpdDownloadInfo(
-                Path(name),
-                url=self._abs_url_from_link(link),
-                modification_date=modification_date
-            ))
-
-        return items
-
-
-class IpdDownloader:
-    """
-    A downloader for ipd files.
-    """
-
-    def __init__(self, tmp_dir: TmpDir, organizer: Organizer, strategy: IpdDownloadStrategy):
-        self._tmp_dir = tmp_dir
-        self._organizer = organizer
-        self._strategy = strategy
-        self._session = requests.session()
-
-    def download_all(self, infos: List[IpdDownloadInfo]) -> None:
-        """
-        Download multiple files one after the other.
-        """
-        for info in infos:
-            self.download(info)
-
-    def download(self, info: IpdDownloadInfo) -> None:
-        """
-        Download a single file.
-        """
-        if not self._strategy(self._organizer, info):
-            self._organizer.mark(info.path)
-            return
-
-        with self._session.get(info.url, stream=True) as response:
-            if response.status_code == 200:
-                tmp_file = self._tmp_dir.new_path()
-                stream_to_path(response, tmp_file, info.path.name)
-                dst_path = self._organizer.accept_file(tmp_file, info.path)
-
-                if dst_path and info.modification_date:
-                    os.utime(
-                        dst_path,
-                        times=(
-                            math.ceil(info.modification_date.timestamp()),
-                            math.ceil(info.modification_date.timestamp())
-                        )
-                    )
-
-            elif response.status_code == 403:
-                raise FatalException("Received 403. Are you not using the KIT VPN?")
-            else:
-                PRETTY.warning(f"Could not download file, got response {response.status_code}")

PFERD/limiter.py

@@ -0,0 +1,97 @@
+import asyncio
+import time
+from contextlib import asynccontextmanager
+from dataclasses import dataclass
+from typing import AsyncIterator, Optional
+
+
+@dataclass
+class Slot:
+    active: bool = False
+    last_left: Optional[float] = None
+
+
+class Limiter:
+    def __init__(
+            self,
+            task_limit: int,
+            download_limit: int,
+            task_delay: float
+    ):
+        if task_limit <= 0:
+            raise ValueError("task limit must be at least 1")
+        if download_limit <= 0:
+            raise ValueError("download limit must be at least 1")
+        if download_limit > task_limit:
+            raise ValueError("download limit can't be greater than task limit")
+        if task_delay < 0:
+            raise ValueError("Task delay must not be negative")
+
+        self._slots = [Slot() for _ in range(task_limit)]
+        self._downloads = download_limit
+        self._delay = task_delay
+
+        self._condition = asyncio.Condition()
+
+    def _acquire_slot(self) -> Optional[Slot]:
+        for slot in self._slots:
+            if not slot.active:
+                slot.active = True
+                return slot
+
+        return None
+
+    async def _wait_for_slot_delay(self, slot: Slot) -> None:
+        if slot.last_left is not None:
+            delay = slot.last_left + self._delay - time.time()
+            if delay > 0:
+                await asyncio.sleep(delay)
+
+    def _release_slot(self, slot: Slot) -> None:
+        slot.last_left = time.time()
+        slot.active = False
+
+    @asynccontextmanager
+    async def limit_crawl(self) -> AsyncIterator[None]:
+        slot: Slot
+        async with self._condition:
+            while True:
+                if found_slot := self._acquire_slot():
+                    slot = found_slot
+                    break
+                await self._condition.wait()
+
+        await self._wait_for_slot_delay(slot)
+
+        try:
+            yield
+        finally:
+            async with self._condition:
+                self._release_slot(slot)
+                self._condition.notify_all()
+
+    @asynccontextmanager
+    async def limit_download(self) -> AsyncIterator[None]:
+        slot: Slot
+        async with self._condition:
+            while True:
+                if self._downloads <= 0:
+                    await self._condition.wait()
+                    continue
+
+                if found_slot := self._acquire_slot():
+                    slot = found_slot
+                    self._downloads -= 1
+                    break
+
+                await self._condition.wait()
+
+        await self._wait_for_slot_delay(slot)
+
+        try:
+            yield
+        finally:
+            async with self._condition:
+                self._release_slot(slot)
+                self._downloads += 1
+                self._condition.notify_all()

PFERD/location.py

@@ -1,41 +0,0 @@
-"""
-Contains a Location class for objects with an inherent path.
-"""
-
-from pathlib import Path, PurePath
-
-
-class ResolveException(Exception):
-    """An exception while resolving a file."""
-    # TODO take care of this when doing exception handling
-
-
-class Location:
-    """
-    An object that has an inherent path.
-    """
-
-    def __init__(self, path: Path):
-        self._path = path.resolve()
-
-    @property
-    def path(self) -> Path:
-        """
-        This object's location.
-        """
-
-        return self._path
-
-    def resolve(self, target: PurePath) -> Path:
-        """
-        Resolve a file relative to the path of this location.
-
-        Raises a [ResolveException] if the file is outside the given directory.
-        """
-        absolute_path = self.path.joinpath(target).resolve()
-
-        # TODO Make this less inefficient
-        if self.path not in absolute_path.parents:
-            raise ResolveException(f"Path {target} is not inside directory {self.path}")
-
-        return absolute_path

PFERD/logging.py

@@ -1,184 +1,291 @@
-"""
-Contains a few logger utility functions and implementations.
-"""
+import asyncio
+import sys
+import traceback
+from contextlib import asynccontextmanager, contextmanager
+# TODO In Python 3.9 and above, ContextManager is deprecated
+from typing import AsyncIterator, ContextManager, Iterator, List, Optional
 
-import logging
-from typing import Optional
-
-from rich._log_render import LogRender
-from rich.console import Console
-from rich.style import Style
-from rich.text import Text
-from rich.theme import Theme
-
-from .download_summary import DownloadSummary
-from .utils import PathLike, to_path
-
-STYLE = "{"
-FORMAT = "[{levelname:<7}] {message}"
-DATE_FORMAT = "%F %T"
+from rich.console import Console, Group
+from rich.live import Live
+from rich.markup import escape
+from rich.panel import Panel
+from rich.progress import (BarColumn, DownloadColumn, Progress, TaskID, TextColumn, TimeRemainingColumn,
+                           TransferSpeedColumn)
+from rich.table import Column
 
 
-def enable_logging(name: str = "PFERD", level: int = logging.INFO) -> None:
-    """
-    Enable and configure logging via the logging module.
-    """
+class ProgressBar:
+    def __init__(self, progress: Progress, taskid: TaskID):
+        self._progress = progress
+        self._taskid = taskid
 
-    logger = logging.getLogger(name)
-    logger.setLevel(level)
-    logger.addHandler(RichLoggingHandler(level=level))
+    def advance(self, amount: float = 1) -> None:
+        self._progress.advance(self._taskid, advance=amount)
 
-    # This should be logged by our own handler, and not the root logger's
-    # default handler, so we don't pass it on to the root logger.
-    logger.propagate = False
+    def set_total(self, total: float) -> None:
+        self._progress.update(self._taskid, total=total)
+        self._progress.start_task(self._taskid)
 
 
-class RichLoggingHandler(logging.Handler):
-    """
-    A logging handler that uses rich for highlighting
-    """
+class Log:
+    STATUS_WIDTH = 11
 
-    def __init__(self, level: int) -> None:
-        super().__init__(level=level)
-        self.console = Console(theme=Theme({
-            "logging.level.warning": Style(color="yellow")
-        }))
-        self._log_render = LogRender(show_level=True, show_time=False, show_path=False)
+    def __init__(self) -> None:
+        self.console = Console(highlight=False)
 
-    def emit(self, record: logging.LogRecord) -> None:
-        """
-        Invoked by logging.
-        """
-        log_style = f"logging.level.{record.levelname.lower()}"
-        message = self.format(record)
-
-        level = Text()
-        level.append(record.levelname, log_style)
-        message_text = Text.from_markup(message)
-
-        self.console.print(
-            self._log_render(
-                self.console,
-                [message_text],
-                level=level,
-            )
+        self._crawl_progress = Progress(
+            TextColumn("{task.description}", table_column=Column(ratio=1)),
+            BarColumn(),
+            TimeRemainingColumn(),
+            expand=True,
+        )
+        self._download_progress = Progress(
+            TextColumn("{task.description}", table_column=Column(ratio=1)),
+            TransferSpeedColumn(),
+            DownloadColumn(),
+            BarColumn(),
+            TimeRemainingColumn(),
+            expand=True,
         )
 
+        self._live = Live(console=self.console, transient=True)
+        self._update_live()
 
-class PrettyLogger:
-    """
-    A logger that prints some specially formatted log messages in color.
-    """
+        self._showing_progress = False
+        self._progress_suspended = False
+        self._lock = asyncio.Lock()
+        self._lines: List[str] = []
 
-    def __init__(self, logger: logging.Logger) -> None:
-        self.logger = logger
+        # Whether different parts of the output are enabled or disabled
+        self.output_explain = False
+        self.output_status = True
+        self.output_not_deleted = True
+        self.output_report = True
 
-    @staticmethod
-    def _format_path(path: PathLike) -> str:
-        return repr(str(to_path(path)))
+    def _update_live(self) -> None:
+        elements = []
+        if self._crawl_progress.task_ids:
+            elements.append(self._crawl_progress)
+        if self._download_progress.task_ids:
+            elements.append(self._download_progress)
 
-    def error(self, message: str) -> None:
+        group = Group(*elements)
+        self._live.update(group)
+
+    @contextmanager
+    def show_progress(self) -> Iterator[None]:
+        if self._showing_progress:
+            raise RuntimeError("Calling 'show_progress' while already showing progress")
+
+        self._showing_progress = True
+        try:
+            with self._live:
+                yield
+        finally:
+            self._showing_progress = False
+
+    @asynccontextmanager
+    async def exclusive_output(self) -> AsyncIterator[None]:
+        if not self._showing_progress:
+            raise RuntimeError("Calling 'exclusive_output' while not showing progress")
+
+        async with self._lock:
+            self._progress_suspended = True
+            self._live.stop()
+            try:
+                yield
+            finally:
+                self._live.start()
+                self._progress_suspended = False
+                for line in self._lines:
+                    self.print(line)
+                self._lines = []
+
+    def unlock(self) -> None:
         """
-        Print an error message indicating some operation fatally failed.
-        """
-        self.logger.error(
-            f"[bold red]{message}[/bold red]"
-        )
+        Get rid of an exclusive output state.
 
-    def warning(self, message: str) -> None:
-        """
-        Print a warning message indicating some operation failed, but the error can be recovered
-        or ignored.
-        """
-        self.logger.warning(
-            f"[bold yellow]{message}[/bold yellow]"
-        )
-
-    def modified_file(self, path: PathLike) -> None:
-        """
-        An existing file has changed.
+        This function is meant to let PFERD print log messages after the event
+        loop was forcibly stopped and if it will not be started up again. After
+        this is called, it is not safe to use any functions except the logging
+        functions (print, warn, ...).
         """
 
-        self.logger.info(
-            f"[bold magenta]Modified {self._format_path(path)}.[/bold magenta]"
-        )
+        self._progress_suspended = False
+        for line in self._lines:
+            self.print(line)
 
-    def new_file(self, path: PathLike) -> None:
+    def print(self, text: str) -> None:
         """
-        A new file has been downloaded.
+        Print a normal message. Allows markup.
         """
 
-        self.logger.info(
-            f"[bold green]Created {self._format_path(path)}.[/bold green]"
-        )
+        if self._progress_suspended:
+            self._lines.append(text)
+        else:
+            self.console.print(text)
 
-    def deleted_file(self, path: PathLike) -> None:
+    # TODO Print errors (and warnings?) to stderr
+
+    def warn(self, text: str) -> None:
         """
-        A file has been deleted.
+        Print a warning message. Allows no markup.
         """
 
-        self.logger.info(
-            f"[bold red]Deleted {self._format_path(path)}.[/bold red]"
-        )
+        self.print(f"[bold bright_red]Warning[/] {escape(text)}")
 
-    def ignored_file(self, path: PathLike, reason: str) -> None:
+    def warn_contd(self, text: str) -> None:
         """
-        File was not downloaded or modified.
+        Print further lines of a warning message. Allows no markup.
         """
 
-        self.logger.info(
-            f"[dim]Ignored {self._format_path(path)} "
-            f"([/dim]{reason}[dim]).[/dim]"
-        )
+        self.print(f"{escape(text)}")
 
-    def searching(self, path: PathLike) -> None:
+    def error(self, text: str) -> None:
         """
-        A crawler searches a particular object.
+        Print an error message. Allows no markup.
         """
 
-        self.logger.info(f"Searching {self._format_path(path)}")
+        self.print(f"[bold bright_red]Error[/] [red]{escape(text)}")
 
-    def not_searching(self, path: PathLike, reason: str) -> None:
+    def error_contd(self, text: str) -> None:
         """
-        A crawler does not search a particular object.
+        Print further lines of an error message. Allows no markup.
         """
 
-        self.logger.info(
-            f"[dim]Not searching {self._format_path(path)} "
-            f"([/dim]{reason}[dim]).[/dim]"
-        )
+        self.print(f"[red]{escape(text)}")
 
-    def summary(self, download_summary: DownloadSummary) -> None:
+    def unexpected_exception(self) -> None:
         """
-        Prints a download summary.
+        Call this in an "except" clause to log an unexpected exception.
         """
-        self.logger.info("")
-        self.logger.info("[bold cyan]Download Summary[/bold cyan]")
-        if not download_summary.has_updates():
-            self.logger.info("[bold dim]Nothing changed![/bold dim]")
-            return
 
-        for new_file in download_summary.new_files:
-            self.new_file(new_file)
-        for modified_file in download_summary.modified_files:
-            self.modified_file(modified_file)
-        for deleted_files in download_summary.deleted_files:
-            self.deleted_file(deleted_files)
+        t, v, tb = sys.exc_info()
+        if t is None or v is None or tb is None:
+            # We're not currently handling an exception, so somebody probably
+            # called this function where they shouldn't.
+            self.error("Something unexpected happened")
+            self.error_contd("")
+            for line in traceback.format_stack():
+                self.error_contd(line[:-1])  # Without the newline
+            self.error_contd("")
+        else:
+            self.error("An unexpected exception occurred")
+            self.error_contd("")
+            self.error_contd(traceback.format_exc())
 
-    def starting_synchronizer(
+        # Our print function doesn't take types other than strings, but the
+        # underlying rich.print function does. This call is a special case
+        # anyways, and we're calling it internally, so this should be fine.
+        self.print(Panel.fit("""
+Please copy your program output and send it to the PFERD maintainers, either
+directly or as a GitHub issue: https://github.com/Garmelon/PFERD/issues/new
+        """.strip()))  # type: ignore
+
+    def explain_topic(self, text: str) -> None:
+        """
+        Print a top-level explain text. Allows no markup.
+        """
+
+        if self.output_explain:
+            self.print(f"[yellow]{escape(text)}")
+
+    def explain(self, text: str) -> None:
+        """
+        Print an indented explain text. Allows no markup.
+        """
+
+        if self.output_explain:
+            self.print(f"  {escape(text)}")
+
+    def status(self, style: str, action: str, text: str, suffix: str = "") -> None:
+        """
+        Print a status update while crawling. Allows markup in the "style"
+        argument which will be applied to the "action" string.
+        """
+
+        if self.output_status:
+            action = escape(f"{action:<{self.STATUS_WIDTH}}")
+            self.print(f"{style}{action}[/] {escape(text)} {suffix}")
+
+    def not_deleted(self, style: str, action: str, text: str, suffix: str = "") -> None:
+        """
+        Print a message for a local only file that wasn't
+        deleted while crawling. Allows markup in the "style"
+        argument which will be applied to the "action" string.
+        """
+
+        if self.output_status and self.output_not_deleted:
+            action = escape(f"{action:<{self.STATUS_WIDTH}}")
+            self.print(f"{style}{action}[/] {escape(text)} {suffix}")
+
+    def report(self, text: str) -> None:
+        """
+        Print a report after crawling. Allows markup.
+        """
+
+        if self.output_report:
+            self.print(text)
+
+    def report_not_deleted(self, text: str) -> None:
+        """
+        Print a report for a local only file that wasn't deleted after crawling. Allows markup.
+        """
+
+        if self.output_report and self.output_not_deleted:
+            self.print(text)
+
+    @contextmanager
+    def _bar(
             self,
-            target_directory: PathLike,
-            synchronizer_name: str,
-            subject: Optional[str] = None,
-    ) -> None:
+            progress: Progress,
+            description: str,
+            total: Optional[float],
+    ) -> Iterator[ProgressBar]:
+        if total is None:
+            # Indeterminate progress bar
+            taskid = progress.add_task(description, start=False)
+        else:
+            taskid = progress.add_task(description, total=total)
+        self._update_live()
+
+        try:
+            yield ProgressBar(progress, taskid)
+        finally:
+            progress.remove_task(taskid)
+            self._update_live()
+
+    def crawl_bar(
+            self,
+            style: str,
+            action: str,
+            text: str,
+            total: Optional[float] = None,
+    ) -> ContextManager[ProgressBar]:
         """
-        A special message marking that a synchronizer has been started.
+        Allows markup in the "style" argument which will be applied to the
+        "action" string.
         """
 
-        subject_str = f"{subject} " if subject else ""
-        self.logger.info("")
-        self.logger.info((
-            f"[bold cyan]Synchronizing "
-            f"{subject_str}to {self._format_path(target_directory)} "
-            f"using the {synchronizer_name} synchronizer.[/bold cyan]"
-        ))
+        action = escape(f"{action:<{self.STATUS_WIDTH}}")
+        description = f"{style}{action}[/] {text}"
+        return self._bar(self._crawl_progress, description, total)
+
+    def download_bar(
+            self,
+            style: str,
+            action: str,
+            text: str,
+            total: Optional[float] = None,
+    ) -> ContextManager[ProgressBar]:
+        """
+        Allows markup in the "style" argument which will be applied to the
+        "action" string.
+        """
+
+        action = escape(f"{action:<{self.STATUS_WIDTH}}")
+        description = f"{style}{action}[/] {text}"
+        return self._bar(self._download_progress, description, total)
+
+
+log = Log()

PFERD/organizer.py

@@ -1,224 +0,0 @@
-"""A simple helper for managing downloaded files.
-
-A organizer is bound to a single directory.
-"""
-
-import filecmp
-import logging
-import os
-import shutil
-from enum import Enum
-from pathlib import Path, PurePath
-from typing import Callable, List, Optional, Set
-
-from .download_summary import DownloadSummary
-from .location import Location
-from .logging import PrettyLogger
-from .utils import prompt_yes_no
-
-LOGGER = logging.getLogger(__name__)
-PRETTY = PrettyLogger(LOGGER)
-
-
-class ConflictType(Enum):
-    """
-    The type of the conflict. A file might not exist anymore and will be deleted
-    or it might be overwritten with a newer version.
-
-    FILE_OVERWRITTEN: An existing file will be updated
-    MARKED_FILE_OVERWRITTEN: A file is written for the second+ time in this run
-    FILE_DELETED: The file was deleted
-    """
-    FILE_OVERWRITTEN = "overwritten"
-    MARKED_FILE_OVERWRITTEN = "marked_file_overwritten"
-    FILE_DELETED = "deleted"
-
-
-class FileConflictResolution(Enum):
-    """
-    The reaction when confronted with a file conflict:
-
-    DESTROY_EXISTING: Delete/overwrite the current file
-    KEEP_EXISTING: Keep the current file
-    DEFAULT: Do whatever the PFERD authors thought is sensible
-    PROMPT: Interactively ask the user
-    """
-
-    DESTROY_EXISTING = "destroy"
-
-    KEEP_EXISTING = "keep"
-
-    DEFAULT = "default"
-
-    PROMPT = "prompt"
-
-
-FileConflictResolver = Callable[[PurePath, ConflictType], FileConflictResolution]
-
-
-def resolve_prompt_user(_path: PurePath, conflict: ConflictType) -> FileConflictResolution:
-    """
-    Resolves conflicts by asking the user if a file was written twice or will be deleted.
-    """
-    if conflict == ConflictType.FILE_OVERWRITTEN:
-        return FileConflictResolution.DESTROY_EXISTING
-    return FileConflictResolution.PROMPT
-
-
-class FileAcceptException(Exception):
-    """An exception while accepting a file."""
-
-
-class Organizer(Location):
-    """A helper for managing downloaded files."""
-
-    def __init__(self, path: Path, conflict_resolver: FileConflictResolver = resolve_prompt_user):
-        """Create a new organizer for a given path."""
-        super().__init__(path)
-        self._known_files: Set[Path] = set()
-
-        # Keep the root dir
-        self._known_files.add(path.resolve())
-
-        self.download_summary = DownloadSummary()
-
-        self.conflict_resolver = conflict_resolver
-
-    def accept_file(self, src: Path, dst: PurePath) -> Optional[Path]:
-        """
-        Move a file to this organizer and mark it.
-
-        Returns the path the file was moved to, to allow the caller to adjust the metadata.
-        As you might still need to adjust the metadata when the file was identical
-        (e.g. update the timestamp), the path is also returned in this case.
-        In all other cases (ignored, not overwritten, etc.) this method returns None.
-        """
-        # Windows limits the path length to 260 for *some* historical reason
-        # If you want longer paths, you will have to add the "\\?\" prefix in front of
-        # your path...
-        # See:
-        # https://docs.microsoft.com/en-us/windows/win32/fileio/naming-a-file#maximum-path-length-limitation
-        if os.name == 'nt':
-            src_absolute = Path("\\\\?\\" + str(src.resolve()))
-            dst_absolute = Path("\\\\?\\" + str(self.resolve(dst)))
-        else:
-            src_absolute = src.resolve()
-            dst_absolute = self.resolve(dst)
-
-        if not src_absolute.exists():
-            raise FileAcceptException("Source file does not exist")
-
-        if not src_absolute.is_file():
-            raise FileAcceptException("Source is a directory")
-
-        LOGGER.debug("Copying %s to %s", src_absolute, dst_absolute)
-
-        if self._is_marked(dst):
-            PRETTY.warning(f"File {str(dst_absolute)!r} was already written!")
-            conflict = ConflictType.MARKED_FILE_OVERWRITTEN
-            if self._resolve_conflict("Overwrite file?", dst_absolute, conflict, default=False):
-                PRETTY.ignored_file(dst_absolute, "file was written previously")
-                return None
-
-        # Destination file is directory
-        if dst_absolute.exists() and dst_absolute.is_dir():
-            prompt = f"Overwrite folder {dst_absolute} with file?"
-            conflict = ConflictType.FILE_OVERWRITTEN
-            if self._resolve_conflict(prompt, dst_absolute, conflict, default=False):
-                shutil.rmtree(dst_absolute)
-            else:
-                PRETTY.warning(f"Could not add file {str(dst_absolute)!r}")
-                return None
-
-        # Destination file exists
-        if dst_absolute.exists() and dst_absolute.is_file():
-            if filecmp.cmp(str(src_absolute), str(dst_absolute), shallow=False):
-                # Bail out, nothing more to do
-                PRETTY.ignored_file(dst_absolute, "same file contents")
-                self.mark(dst)
-                return dst_absolute
-
-            prompt = f"Overwrite file {dst_absolute}?"
-            conflict = ConflictType.FILE_OVERWRITTEN
-            if not self._resolve_conflict(prompt, dst_absolute, conflict, default=True):
-                PRETTY.ignored_file(dst_absolute, "user conflict resolution")
-                return None
-
-            self.download_summary.add_modified_file(dst_absolute)
-            PRETTY.modified_file(dst_absolute)
-        else:
-            self.download_summary.add_new_file(dst_absolute)
-            PRETTY.new_file(dst_absolute)
-
-        # Create parent dir if needed
-        dst_parent_dir: Path = dst_absolute.parent
-        dst_parent_dir.mkdir(exist_ok=True, parents=True)
-
-        # Move file
-        shutil.move(str(src_absolute), str(dst_absolute))
-
-        self.mark(dst)
-
-        return dst_absolute
-
-    def mark(self, path: PurePath) -> None:
-        """Mark a file as used so it will not get cleaned up."""
-        absolute_path = self.resolve(path)
-        self._known_files.add(absolute_path)
-        LOGGER.debug("Tracked %s", absolute_path)
-
-    def _is_marked(self, path: PurePath) -> bool:
-        """
-        Checks whether a file is marked.
-        """
-        absolute_path = self.resolve(path)
-        return absolute_path in self._known_files
-
-    def cleanup(self) -> None:
-        """Remove all untracked files in the organizer's dir."""
-        LOGGER.debug("Deleting all untracked files...")
-
-        self._cleanup(self.path)
-
-    def _cleanup(self, start_dir: Path) -> None:
-        if not start_dir.exists():
-            return
-        paths: List[Path] = list(start_dir.iterdir())
-
-        # Recursively clean paths
-        for path in paths:
-            if path.is_dir():
-                self._cleanup(path)
-            else:
-                if path.resolve() not in self._known_files:
-                    self._delete_file_if_confirmed(path)
-
-        # Delete dir if it was empty and untracked
-        dir_empty = len(list(start_dir.iterdir())) == 0
-        if start_dir.resolve() not in self._known_files and dir_empty:
-            start_dir.rmdir()
-
-    def _delete_file_if_confirmed(self, path: Path) -> None:
-        prompt = f"Do you want to delete {path}"
-
-        if self._resolve_conflict(prompt, path, ConflictType.FILE_DELETED, default=False):
-            self.download_summary.add_deleted_file(path)
-            path.unlink()
-        else:
-            PRETTY.ignored_file(path, "user conflict resolution")
-
-    def _resolve_conflict(
-            self, prompt: str, path: Path, conflict: ConflictType, default: bool
-    ) -> bool:
-        if not self.conflict_resolver:
-            return prompt_yes_no(prompt, default=default)
-
-        result = self.conflict_resolver(path, conflict)
-        if result == FileConflictResolution.DEFAULT:
-            return default
-        if result == FileConflictResolution.KEEP_EXISTING:
-            return False
-        if result == FileConflictResolution.DESTROY_EXISTING:
-            return True
-
-        return prompt_yes_no(prompt, default=default)

PFERD/output_dir.py

@@ -0,0 +1,519 @@
+import filecmp
+import json
+import os
+import random
+import shutil
+import string
+from contextlib import contextmanager
+from dataclasses import dataclass
+from datetime import datetime
+from enum import Enum
+from pathlib import Path, PurePath
+from typing import BinaryIO, Iterator, Optional, Tuple
+
+from .logging import log
+from .report import Report, ReportLoadError
+from .utils import ReusableAsyncContextManager, fmt_path, fmt_real_path, prompt_yes_no
+
+SUFFIX_CHARS = string.ascii_lowercase + string.digits
+SUFFIX_LENGTH = 6
+TRIES = 5
+
+
+class OutputDirError(Exception):
+    pass
+
+
+class Redownload(Enum):
+    NEVER = "never"
+    NEVER_SMART = "never-smart"
+    ALWAYS = "always"
+    ALWAYS_SMART = "always-smart"
+
+    @staticmethod
+    def from_string(string: str) -> "Redownload":
+        try:
+            return Redownload(string)
+        except ValueError:
+            raise ValueError("must be one of 'never', 'never-smart',"
+                             " 'always', 'always-smart'")
+
+
+class OnConflict(Enum):
+    PROMPT = "prompt"
+    LOCAL_FIRST = "local-first"
+    REMOTE_FIRST = "remote-first"
+    NO_DELETE = "no-delete"
+    NO_DELETE_PROMPT_OVERWRITE = "no-delete-prompt-overwrite"
+
+    @staticmethod
+    def from_string(string: str) -> "OnConflict":
+        try:
+            return OnConflict(string)
+        except ValueError:
+            raise ValueError("must be one of 'prompt', 'local-first',"
+                             " 'remote-first', 'no-delete', 'no-delete-prompt-overwrite'")
+
+
+@dataclass
+class Heuristics:
+    mtime: Optional[datetime]
+
+
+class FileSink:
+    def __init__(self, file: BinaryIO):
+        self._file = file
+        self._done = False
+
+    @property
+    def file(self) -> BinaryIO:
+        return self._file
+
+    def done(self) -> None:
+        self._done = True
+
+    def is_done(self) -> bool:
+        return self._done
+
+
+@dataclass
+class DownloadInfo:
+    remote_path: PurePath
+    path: PurePath
+    local_path: Path
+    tmp_path: Path
+    heuristics: Heuristics
+    on_conflict: OnConflict
+    success: bool = False
+
+
+class FileSinkToken(ReusableAsyncContextManager[FileSink]):
+    # Whenever this class is entered, it creates a new temporary file and
+    # returns a corresponding FileSink.
+    #
+    # When it is exited again, the file is closed and information about the
+    # download handed back to the OutputDirectory.
+
+    def __init__(
+            self,
+            output_dir: "OutputDirectory",
+            remote_path: PurePath,
+            path: PurePath,
+            local_path: Path,
+            heuristics: Heuristics,
+            on_conflict: OnConflict,
+    ):
+        super().__init__()
+
+        self._output_dir = output_dir
+        self._remote_path = remote_path
+        self._path = path
+        self._local_path = local_path
+        self._heuristics = heuristics
+        self._on_conflict = on_conflict
+
+    async def _on_aenter(self) -> FileSink:
+        tmp_path, file = await self._output_dir._create_tmp_file(self._local_path)
+        sink = FileSink(file)
+
+        async def after_download() -> None:
+            await self._output_dir._after_download(DownloadInfo(
+                self._remote_path,
+                self._path,
+                self._local_path,
+                tmp_path,
+                self._heuristics,
+                self._on_conflict,
+                sink.is_done(),
+            ))
+
+        self._stack.push_async_callback(after_download)
+        self._stack.enter_context(file)
+
+        return sink
+
+
+class OutputDirectory:
+    REPORT_FILE = PurePath(".report")
+
+    def __init__(
+            self,
+            root: Path,
+            redownload: Redownload,
+            on_conflict: OnConflict,
+    ):
+        if os.name == "nt":
+            # Windows limits the path length to 260 for some historical reason.
+            # If you want longer paths, you will have to add the "\\?\" prefix
+            # in front of your path. See:
+            # https://docs.microsoft.com/en-us/windows/win32/fileio/naming-a-file#maximum-path-length-limitation
+            self._root = Path("\\\\?\\" + str(root.absolute()))
+        else:
+            self._root = root
+
+        self._redownload = redownload
+        self._on_conflict = on_conflict
+
+        self._report_path = self.resolve(self.REPORT_FILE)
+        self._report = Report()
+        self._prev_report: Optional[Report] = None
+
+        self.register_reserved(self.REPORT_FILE)
+
+    @property
+    def report(self) -> Report:
+        return self._report
+
+    @property
+    def prev_report(self) -> Optional[Report]:
+        return self._prev_report
+
+    def prepare(self) -> None:
+        log.explain_topic(f"Creating base directory at {fmt_real_path(self._root)}")
+
+        try:
+            self._root.mkdir(parents=True, exist_ok=True)
+        except OSError:
+            raise OutputDirError("Failed to create base directory")
+
+    def register_reserved(self, path: PurePath) -> None:
+        self._report.mark_reserved(path)
+
+    def resolve(self, path: PurePath) -> Path:
+        """
+        May throw an OutputDirError.
+        """
+
+        if ".." in path.parts:
+            raise OutputDirError(f"Forbidden segment '..' in path {fmt_path(path)}")
+        if "." in path.parts:
+            raise OutputDirError(f"Forbidden segment '.' in path {fmt_path(path)}")
+
+        return self._root / path
+
+    def _should_download(
+            self,
+            local_path: Path,
+            heuristics: Heuristics,
+            redownload: Redownload,
+            on_conflict: OnConflict,
+    ) -> bool:
+        if not local_path.exists():
+            log.explain("No corresponding file present locally")
+            return True
+
+        if on_conflict == OnConflict.LOCAL_FIRST:
+            # Whatever is here, it will never be overwritten, so we don't need
+            # to download the file.
+            log.explain("Conflict resolution is 'local-first' and path exists")
+            return False
+
+        if not local_path.is_file():
+            # We know that there is *something* here that's not a file.
+            log.explain("Non-file (probably a directory) present locally")
+
+            # If on_conflict is LOCAL_FIRST or NO_DELETE, we know that it would
+            # never be overwritten. It also doesn't have any relevant stats to
+            # update. This means that we don't have to download the file
+            # because we'd just always throw it away again.
+            if on_conflict in {OnConflict.LOCAL_FIRST, OnConflict.NO_DELETE}:
+                log.explain(f"Conflict resolution is {on_conflict.value!r}")
+                return False
+
+            return True
+
+        log.explain(f"Redownload policy is {redownload.value}")
+
+        if redownload == Redownload.NEVER:
+            return False
+        elif redownload == Redownload.ALWAYS:
+            return True
+
+        stat = local_path.stat()
+
+        remote_newer = None
+
+        # Python on Windows crashes when faced with timestamps around the unix epoch
+        if heuristics.mtime and (os.name != "nt" or heuristics.mtime.year > 1970):
+            mtime = heuristics.mtime
+            remote_newer = mtime.timestamp() > stat.st_mtime
+            if remote_newer:
+                log.explain("Remote file seems to be newer")
+            else:
+                log.explain("Remote file doesn't seem to be newer")
+
+        if redownload == Redownload.NEVER_SMART:
+            if remote_newer is None:
+                return False
+            else:
+                return remote_newer
+        elif redownload == Redownload.ALWAYS_SMART:
+            if remote_newer is None:
+                return True
+            else:
+                return remote_newer
+
+        # This should never be reached
+        raise ValueError(f"{redownload!r} is not a valid redownload policy")
+
+    # The following conflict resolution functions all return False if the local
+    # file(s) should be kept and True if they should be replaced by the remote
+    # files.
+
+    async def _conflict_lfrf(
+            self,
+            on_conflict: OnConflict,
+            path: PurePath,
+    ) -> bool:
+        if on_conflict in {OnConflict.PROMPT, OnConflict.NO_DELETE_PROMPT_OVERWRITE}:
+            async with log.exclusive_output():
+                prompt = f"Replace {fmt_path(path)} with remote file?"
+                return await prompt_yes_no(prompt, default=False)
+        elif on_conflict == OnConflict.LOCAL_FIRST:
+            return False
+        elif on_conflict == OnConflict.REMOTE_FIRST:
+            return True
+        elif on_conflict == OnConflict.NO_DELETE:
+            return True
+
+        # This should never be reached
+        raise ValueError(f"{on_conflict!r} is not a valid conflict policy")
+
+    async def _conflict_ldrf(
+            self,
+            on_conflict: OnConflict,
+            path: PurePath,
+    ) -> bool:
+        if on_conflict in {OnConflict.PROMPT, OnConflict.NO_DELETE_PROMPT_OVERWRITE}:
+            async with log.exclusive_output():
+                prompt = f"Recursively delete {fmt_path(path)} and replace with remote file?"
+                return await prompt_yes_no(prompt, default=False)
+        elif on_conflict == OnConflict.LOCAL_FIRST:
+            return False
+        elif on_conflict == OnConflict.REMOTE_FIRST:
+            return True
+        elif on_conflict == OnConflict.NO_DELETE:
+            return False
+
+        # This should never be reached
+        raise ValueError(f"{on_conflict!r} is not a valid conflict policy")
+
+    async def _conflict_lfrd(
+            self,
+            on_conflict: OnConflict,
+            path: PurePath,
+            parent: PurePath,
+    ) -> bool:
+        if on_conflict in {OnConflict.PROMPT, OnConflict.NO_DELETE_PROMPT_OVERWRITE}:
+            async with log.exclusive_output():
+                prompt = f"Delete {fmt_path(parent)} so remote file {fmt_path(path)} can be downloaded?"
+                return await prompt_yes_no(prompt, default=False)
+        elif on_conflict == OnConflict.LOCAL_FIRST:
+            return False
+        elif on_conflict == OnConflict.REMOTE_FIRST:
+            return True
+        elif on_conflict == OnConflict.NO_DELETE:
+            return False
+
+        # This should never be reached
+        raise ValueError(f"{on_conflict!r} is not a valid conflict policy")
+
+    async def _conflict_delete_lf(
+            self,
+            on_conflict: OnConflict,
+            path: PurePath,
+    ) -> bool:
+        if on_conflict == OnConflict.PROMPT:
+            async with log.exclusive_output():
+                prompt = f"Delete {fmt_path(path)}?"
+                return await prompt_yes_no(prompt, default=False)
+        elif on_conflict == OnConflict.LOCAL_FIRST:
+            return False
+        elif on_conflict == OnConflict.REMOTE_FIRST:
+            return True
+        elif on_conflict in {OnConflict.NO_DELETE, OnConflict.NO_DELETE_PROMPT_OVERWRITE}:
+            return False
+
+        # This should never be reached
+        raise ValueError(f"{on_conflict!r} is not a valid conflict policy")
+
+    def _tmp_path(self, base: Path, suffix_length: int) -> Path:
+        prefix = "" if base.name.startswith(".") else "."
+        suffix = "".join(random.choices(SUFFIX_CHARS, k=suffix_length))
+        name = f"{prefix}{base.name}.tmp.{suffix}"
+        return base.parent / name
+
+    async def _create_tmp_file(
+            self,
+            local_path: Path,
+    ) -> Tuple[Path, BinaryIO]:
+        """
+        May raise an OutputDirError.
+        """
+
+        # Create tmp file
+        for attempt in range(TRIES):
+            suffix_length = SUFFIX_LENGTH + 2 * attempt
+            tmp_path = self._tmp_path(local_path, suffix_length)
+            try:
+                return tmp_path, open(tmp_path, "xb")
+            except FileExistsError:
+                pass  # Try again
+
+        raise OutputDirError("Failed to create temporary file")
+
+    async def download(
+            self,
+            remote_path: PurePath,
+            path: PurePath,
+            mtime: Optional[datetime] = None,
+            redownload: Optional[Redownload] = None,
+            on_conflict: Optional[OnConflict] = None,
+    ) -> Optional[FileSinkToken]:
+        """
+        May throw an OutputDirError, a MarkDuplicateError or a
+        MarkConflictError.
+        """
+
+        heuristics = Heuristics(mtime)
+        redownload = self._redownload if redownload is None else redownload
+        on_conflict = self._on_conflict if on_conflict is None else on_conflict
+        local_path = self.resolve(path)
+
+        self._report.mark(path)
+
+        if not self._should_download(local_path, heuristics, redownload, on_conflict):
+            return None
+
+        # Detect and solve local-dir-remote-file conflict
+        if local_path.is_dir():
+            log.explain("Conflict: There's a directory in place of the local file")
+            if await self._conflict_ldrf(on_conflict, path):
+                log.explain("Result: Delete the obstructing directory")
+                shutil.rmtree(local_path)
+            else:
+                log.explain("Result: Keep the obstructing directory")
+                return None
+
+        # Detect and solve local-file-remote-dir conflict
+        for parent in path.parents:
+            local_parent = self.resolve(parent)
+            if local_parent.exists() and not local_parent.is_dir():
+                log.explain("Conflict: One of the local file's parents is a file")
+                if await self._conflict_lfrd(on_conflict, path, parent):
+                    log.explain("Result: Delete the obstructing file")
+                    local_parent.unlink()
+                    break
+                else:
+                    log.explain("Result: Keep the obstructing file")
+                    return None
+
+        # Ensure parent directory exists
+        local_path.parent.mkdir(parents=True, exist_ok=True)
+
+        return FileSinkToken(self, remote_path, path, local_path, heuristics, on_conflict)
+
+    def _update_metadata(self, info: DownloadInfo) -> None:
+        if mtime := info.heuristics.mtime:
+            log.explain(f"Setting mtime to {mtime}")
+            mtimestamp = mtime.timestamp()
+            os.utime(info.local_path, times=(mtimestamp, mtimestamp))
+
+    @contextmanager
+    def _ensure_deleted(self, path: Path) -> Iterator[None]:
+        try:
+            yield
+        finally:
+            path.unlink(missing_ok=True)
+
+    async def _after_download(self, info: DownloadInfo) -> None:
+        with self._ensure_deleted(info.tmp_path):
+            log.status("[bold cyan]", "Downloaded", fmt_path(info.remote_path))
+            log.explain_topic(f"Processing downloaded file for {fmt_path(info.path)}")
+
+            changed = False
+
+            if not info.success:
+                log.explain("Download unsuccessful, aborting")
+                return
+
+            # Solve conflicts arising from existing local file
+            if info.local_path.exists():
+                changed = True
+
+                if filecmp.cmp(info.local_path, info.tmp_path):
+                    log.explain("Contents identical with existing file")
+                    log.explain("Updating metadata of existing file")
+                    self._update_metadata(info)
+                    return
+
+                log.explain("Conflict: The local and remote versions differ")
+                if await self._conflict_lfrf(info.on_conflict, info.path):
+                    log.explain("Result: Replacing local with remote version")
+                else:
+                    log.explain("Result: Keeping local version")
+                    return
+
+            info.tmp_path.replace(info.local_path)
+            log.explain("Updating file metadata")
+            self._update_metadata(info)
+
+            if changed:
+                log.status("[bold bright_yellow]", "Changed", fmt_path(info.path))
+                self._report.change_file(info.path)
+            else:
+                log.status("[bold bright_green]", "Added", fmt_path(info.path))
+                self._report.add_file(info.path)
+
+    async def cleanup(self) -> None:
+        await self._cleanup_dir(self._root, PurePath(), delete_self=False)
+
+    async def _cleanup(self, path: Path, pure: PurePath) -> None:
+        if path.is_dir():
+            await self._cleanup_dir(path, pure)
+        elif path.is_file():
+            await self._cleanup_file(path, pure)
+
+    async def _cleanup_dir(self, path: Path, pure: PurePath, delete_self: bool = True) -> None:
+        for child in sorted(path.iterdir()):
+            pure_child = pure / child.name
+            await self._cleanup(child, pure_child)
+
+        if delete_self:
+            try:
+                path.rmdir()
+            except OSError:
+                pass
+
+    async def _cleanup_file(self, path: Path, pure: PurePath) -> None:
+        if self._report.is_marked(pure):
+            return
+
+        if await self._conflict_delete_lf(self._on_conflict, pure):
+            try:
+                path.unlink()
+                log.status("[bold bright_magenta]", "Deleted", fmt_path(pure))
+                self._report.delete_file(pure)
+            except OSError:
+                pass
+        else:
+            log.not_deleted("[bold bright_magenta]", "Not deleted", fmt_path(pure))
+            self._report.not_delete_file(pure)
+
+    def load_prev_report(self) -> None:
+        log.explain_topic(f"Loading previous report from {fmt_real_path(self._report_path)}")
+        try:
+            self._prev_report = Report.load(self._report_path)
+            log.explain("Loaded report successfully")
+        except (OSError, UnicodeDecodeError, json.JSONDecodeError, ReportLoadError) as e:
+            log.explain("Failed to load report")
+            log.explain(str(e))
+
+    def store_report(self) -> None:
+        log.explain_topic(f"Storing report to {fmt_real_path(self._report_path)}")
+        try:
+            self._report.store(self._report_path)
+            log.explain("Stored report successfully")
+        except OSError as e:
+            log.warn(f"Failed to save report to {fmt_real_path(self._report_path)}")
+            log.warn_contd(str(e))

PFERD/pferd.py

@@ -1,440 +1,194 @@
-"""
-Convenience functions for using PFERD.
-"""
-
-import logging
 from pathlib import Path
-from typing import Callable, List, Optional, Union
+from typing import Dict, List, Optional
 
-from .authenticators import UserPassAuthenticator
-from .cookie_jar import CookieJar
-from .diva import (DivaDownloader, DivaDownloadStrategy, DivaPlaylistCrawler,
-                   diva_download_new)
-from .download_summary import DownloadSummary
-from .errors import FatalException, swallow_and_print_errors
-from .ilias import (IliasAuthenticator, IliasCrawler, IliasDirectoryFilter,
-                    IliasDownloader, IliasDownloadInfo, IliasDownloadStrategy,
-                    KitShibbolethAuthenticator, download_modified_or_new)
-from .ipd import (IpdCrawler, IpdDownloader, IpdDownloadInfo,
-                  IpdDownloadStrategy, ipd_download_new_or_modified)
-from .location import Location
-from .logging import PrettyLogger, enable_logging
-from .organizer import FileConflictResolver, Organizer, resolve_prompt_user
-from .tmp_dir import TmpDir
-from .transform import TF, Transform, apply_transform
-from .utils import PathLike, to_path
+from rich.markup import escape
 
-# TODO save known-good cookies as soon as possible
+from .auth import AUTHENTICATORS, Authenticator, AuthError, AuthSection
+from .config import Config, ConfigOptionError
+from .crawl import CRAWLERS, Crawler, CrawlError, CrawlerSection, KitIliasWebCrawler
+from .logging import log
+from .utils import fmt_path
 
 
-LOGGER = logging.getLogger(__name__)
-PRETTY = PrettyLogger(LOGGER)
+class PferdLoadError(Exception):
+    pass
 
 
-class Pferd(Location):
-    # pylint: disable=too-many-arguments
-    """
-    The main entrypoint in your Pferd usage: This class combines a number of
-    useful shortcuts for running synchronizers in a single interface.
-    """
+class Pferd:
+    def __init__(self, config: Config, cli_crawlers: Optional[List[str]], cli_skips: Optional[List[str]]):
+        """
+        May throw PferdLoadError.
+        """
 
-    def __init__(
+        self._config = config
+        self._crawlers_to_run = self._find_crawlers_to_run(config, cli_crawlers, cli_skips)
+
+        self._authenticators: Dict[str, Authenticator] = {}
+        self._crawlers: Dict[str, Crawler] = {}
+
+    def _find_config_crawlers(self, config: Config) -> List[str]:
+        crawl_sections = []
+
+        for name, section in config.crawl_sections():
+            if CrawlerSection(section).skip():
+                log.explain(f"Skipping {name!r}")
+            else:
+                crawl_sections.append(name)
+
+        return crawl_sections
+
+    def _find_cli_crawlers(self, config: Config, cli_crawlers: List[str]) -> List[str]:
+        if len(cli_crawlers) != len(set(cli_crawlers)):
+            raise PferdLoadError("Some crawlers were selected multiple times")
+
+        crawl_sections = [name for name, _ in config.crawl_sections()]
+
+        crawlers_to_run = []  # With crawl: prefix
+        unknown_names = []  # Without crawl: prefix
+
+        for name in cli_crawlers:
+            section_name = f"crawl:{name}"
+            if section_name in crawl_sections:
+                log.explain(f"Crawler section named {section_name!r} exists")
+                crawlers_to_run.append(section_name)
+            else:
+                log.explain(f"There's no crawler section named {section_name!r}")
+                unknown_names.append(name)
+
+        if unknown_names:
+            if len(unknown_names) == 1:
+                [name] = unknown_names
+                raise PferdLoadError(f"There is no crawler named {name!r}")
+            else:
+                names_str = ", ".join(repr(name) for name in unknown_names)
+                raise PferdLoadError(f"There are no crawlers named {names_str}")
+
+        return crawlers_to_run
+
+    def _find_crawlers_to_run(
             self,
-            base_dir: Path,
-            tmp_dir: Path = Path(".tmp"),
-            test_run: bool = False
-    ):
-        super().__init__(Path(base_dir))
+            config: Config,
+            cli_crawlers: Optional[List[str]],
+            cli_skips: Optional[List[str]],
+    ) -> List[str]:
+        log.explain_topic("Deciding which crawlers to run")
 
-        self._download_summary = DownloadSummary()
-        self._tmp_dir = TmpDir(self.resolve(tmp_dir))
-        self._test_run = test_run
-
-    @staticmethod
-    def enable_logging() -> None:
-        """
-        Enable and configure logging via the logging module.
-        """
-
-        enable_logging()
-
-    @staticmethod
-    def _print_transformables(transformables: List[TF]) -> None:
-        LOGGER.info("")
-        LOGGER.info("Results of the test run:")
-        for transformable in transformables:
-            LOGGER.info(transformable.path)
-
-    @staticmethod
-    def _get_authenticator(
-            username: Optional[str], password: Optional[str]
-    ) -> KitShibbolethAuthenticator:
-        inner_auth = UserPassAuthenticator("ILIAS - Pferd.py", username, password)
-        return KitShibbolethAuthenticator(inner_auth)
-
-    def _ilias(
-            self,
-            target: PathLike,
-            base_url: str,
-            crawl_function: Callable[[IliasCrawler], List[IliasDownloadInfo]],
-            authenticator: IliasAuthenticator,
-            cookies: Optional[PathLike],
-            dir_filter: IliasDirectoryFilter,
-            transform: Transform,
-            download_strategy: IliasDownloadStrategy,
-            timeout: int,
-            clean: bool = True,
-            file_conflict_resolver: FileConflictResolver = resolve_prompt_user
-    ) -> Organizer:
-        # pylint: disable=too-many-locals
-        cookie_jar = CookieJar(to_path(cookies) if cookies else None)
-        session = cookie_jar.create_session()
-        tmp_dir = self._tmp_dir.new_subdir()
-        organizer = Organizer(self.resolve(to_path(target)), file_conflict_resolver)
-
-        crawler = IliasCrawler(base_url, session, authenticator, dir_filter)
-        downloader = IliasDownloader(tmp_dir, organizer, session,
-                                     authenticator, download_strategy, timeout)
-
-        cookie_jar.load_cookies()
-        info = crawl_function(crawler)
-        cookie_jar.save_cookies()
-
-        transformed = apply_transform(transform, info)
-        if self._test_run:
-            self._print_transformables(transformed)
-            return organizer
-
-        downloader.download_all(transformed)
-        cookie_jar.save_cookies()
-
-        if clean:
-            organizer.cleanup()
-
-        return organizer
-
-    @swallow_and_print_errors
-    def ilias_kit(
-            self,
-            target: PathLike,
-            course_id: str,
-            dir_filter: IliasDirectoryFilter = lambda x, y: True,
-            transform: Transform = lambda x: x,
-            cookies: Optional[PathLike] = None,
-            username: Optional[str] = None,
-            password: Optional[str] = None,
-            download_strategy: IliasDownloadStrategy = download_modified_or_new,
-            clean: bool = True,
-            timeout: int = 5,
-            file_conflict_resolver: FileConflictResolver = resolve_prompt_user
-    ) -> Organizer:
-        """
-        Synchronizes a folder with the ILIAS instance of the KIT.
-
-        Arguments:
-            target {Path} -- the target path to write the data to
-            course_id {str} -- the id of the main course page (found in the URL after ref_id
-                when opening the course homepage)
-
-        Keyword Arguments:
-            dir_filter {IliasDirectoryFilter} -- A filter for directories. Will be applied on the
-                crawler level, these directories and all of their content is skipped.
-                (default: {lambdax:True})
-            transform {Transform} -- A transformation function for the output paths. Return None
-                to ignore a file. (default: {lambdax:x})
-            cookies {Optional[Path]} -- The path to store and load cookies from.
-                (default: {None})
-            username {Optional[str]} -- The SCC username. If none is given, it will prompt
-                the user. (default: {None})
-            password {Optional[str]} -- The SCC password. If none is given, it will prompt
-                the user. (default: {None})
-            download_strategy {DownloadStrategy} -- A function to determine which files need to
-                be downloaded. Can save bandwidth and reduce the number of requests.
-                (default: {download_modified_or_new})
-            clean {bool} -- Whether to clean up when the method finishes.
-            timeout {int} -- The download timeout for opencast videos. Sadly needed due to a
-                requests bug.
-            file_conflict_resolver {FileConflictResolver} -- A function specifying how to deal
-                with overwriting or deleting files. The default always asks the user.
-        """
-        # This authenticator only works with the KIT ilias instance.
-        authenticator = Pferd._get_authenticator(username=username, password=password)
-        PRETTY.starting_synchronizer(target, "ILIAS", course_id)
-
-        organizer = self._ilias(
-            target=target,
-            base_url="https://ilias.studium.kit.edu/",
-            crawl_function=lambda crawler: crawler.crawl_course(course_id),
-            authenticator=authenticator,
-            cookies=cookies,
-            dir_filter=dir_filter,
-            transform=transform,
-            download_strategy=download_strategy,
-            clean=clean,
-            timeout=timeout,
-            file_conflict_resolver=file_conflict_resolver
-        )
-
-        self._download_summary.merge(organizer.download_summary)
-
-        return organizer
-
-    def print_summary(self) -> None:
-        """
-        Prints the accumulated download summary.
-        """
-        PRETTY.summary(self._download_summary)
-
-    @swallow_and_print_errors
-    def ilias_kit_personal_desktop(
-            self,
-            target: PathLike,
-            dir_filter: IliasDirectoryFilter = lambda x, y: True,
-            transform: Transform = lambda x: x,
-            cookies: Optional[PathLike] = None,
-            username: Optional[str] = None,
-            password: Optional[str] = None,
-            download_strategy: IliasDownloadStrategy = download_modified_or_new,
-            clean: bool = True,
-            timeout: int = 5,
-            file_conflict_resolver: FileConflictResolver = resolve_prompt_user
-    ) -> Organizer:
-        """
-        Synchronizes a folder with the ILIAS instance of the KIT. This method will crawl the ILIAS
-        "personal desktop" instead of a single course.
-
-        Arguments:
-            target {Path} -- the target path to write the data to
-
-        Keyword Arguments:
-            dir_filter {IliasDirectoryFilter} -- A filter for directories. Will be applied on the
-                crawler level, these directories and all of their content is skipped.
-                (default: {lambdax:True})
-            transform {Transform} -- A transformation function for the output paths. Return None
-                to ignore a file. (default: {lambdax:x})
-            cookies {Optional[Path]} -- The path to store and load cookies from.
-                (default: {None})
-            username {Optional[str]} -- The SCC username. If none is given, it will prompt
-                the user. (default: {None})
-            password {Optional[str]} -- The SCC password. If none is given, it will prompt
-                the user. (default: {None})
-            download_strategy {DownloadStrategy} -- A function to determine which files need to
-                be downloaded. Can save bandwidth and reduce the number of requests.
-                (default: {download_modified_or_new})
-            clean {bool} -- Whether to clean up when the method finishes.
-            timeout {int} -- The download timeout for opencast videos. Sadly needed due to a
-                requests bug.
-            file_conflict_resolver {FileConflictResolver} -- A function specifying how to deal
-                with overwriting or deleting files. The default always asks the user.
-        """
-        # This authenticator only works with the KIT ilias instance.
-        authenticator = Pferd._get_authenticator(username, password)
-        PRETTY.starting_synchronizer(target, "ILIAS", "Personal Desktop")
-
-        organizer = self._ilias(
-            target=target,
-            base_url="https://ilias.studium.kit.edu/",
-            crawl_function=lambda crawler: crawler.crawl_personal_desktop(),
-            authenticator=authenticator,
-            cookies=cookies,
-            dir_filter=dir_filter,
-            transform=transform,
-            download_strategy=download_strategy,
-            clean=clean,
-            timeout=timeout,
-            file_conflict_resolver=file_conflict_resolver
-        )
-
-        self._download_summary.merge(organizer.download_summary)
-
-        return organizer
-
-    @swallow_and_print_errors
-    def ilias_kit_folder(
-            self,
-            target: PathLike,
-            full_url: str,
-            dir_filter: IliasDirectoryFilter = lambda x, y: True,
-            transform: Transform = lambda x: x,
-            cookies: Optional[PathLike] = None,
-            username: Optional[str] = None,
-            password: Optional[str] = None,
-            download_strategy: IliasDownloadStrategy = download_modified_or_new,
-            clean: bool = True,
-            timeout: int = 5,
-            file_conflict_resolver: FileConflictResolver = resolve_prompt_user
-    ) -> Organizer:
-        """
-        Synchronizes a folder with a given folder on the ILIAS instance of the KIT.
-
-        Arguments:
-            target {Path}  -- the target path to write the data to
-            full_url {str} -- the full url of the folder/videos/course to crawl
-
-        Keyword Arguments:
-            dir_filter {IliasDirectoryFilter} -- A filter for directories. Will be applied on the
-                crawler level, these directories and all of their content is skipped.
-                (default: {lambdax:True})
-            transform {Transform} -- A transformation function for the output paths. Return None
-                to ignore a file. (default: {lambdax:x})
-            cookies {Optional[Path]} -- The path to store and load cookies from.
-                (default: {None})
-            username {Optional[str]} -- The SCC username. If none is given, it will prompt
-                the user. (default: {None})
-            password {Optional[str]} -- The SCC password. If none is given, it will prompt
-                the user. (default: {None})
-            download_strategy {DownloadStrategy} -- A function to determine which files need to
-                be downloaded. Can save bandwidth and reduce the number of requests.
-                (default: {download_modified_or_new})
-            clean {bool} -- Whether to clean up when the method finishes.
-            timeout {int} -- The download timeout for opencast videos. Sadly needed due to a
-                requests bug.
-            file_conflict_resolver {FileConflictResolver} -- A function specifying how to deal
-                with overwriting or deleting files. The default always asks the user.
-        """
-        # This authenticator only works with the KIT ilias instance.
-        authenticator = Pferd._get_authenticator(username=username, password=password)
-        PRETTY.starting_synchronizer(target, "ILIAS", "An ILIAS element by url")
-
-        if not full_url.startswith("https://ilias.studium.kit.edu"):
-            raise FatalException("Not a valid KIT ILIAS URL")
-
-        organizer = self._ilias(
-            target=target,
-            base_url="https://ilias.studium.kit.edu/",
-            crawl_function=lambda crawler: crawler.recursive_crawl_url(full_url),
-            authenticator=authenticator,
-            cookies=cookies,
-            dir_filter=dir_filter,
-            transform=transform,
-            download_strategy=download_strategy,
-            clean=clean,
-            timeout=timeout,
-            file_conflict_resolver=file_conflict_resolver
-        )
-
-        self._download_summary.merge(organizer.download_summary)
-
-        return organizer
-
-    @swallow_and_print_errors
-    def ipd_kit(
-            self,
-            target: Union[PathLike, Organizer],
-            url: str,
-            transform: Transform = lambda x: x,
-            download_strategy: IpdDownloadStrategy = ipd_download_new_or_modified,
-            clean: bool = True,
-            file_conflict_resolver: FileConflictResolver = resolve_prompt_user
-    ) -> Organizer:
-        """
-        Synchronizes a folder with a DIVA playlist.
-
-        Arguments:
-            target {Union[PathLike, Organizer]} -- The organizer / target folder to use.
-            url {str} -- the url to the page
-
-        Keyword Arguments:
-            transform {Transform} -- A transformation function for the output paths. Return None
-                to ignore a file. (default: {lambdax:x})
-            download_strategy {DivaDownloadStrategy} -- A function to determine which files need to
-                be downloaded. Can save bandwidth and reduce the number of requests.
-                (default: {diva_download_new})
-            clean {bool} -- Whether to clean up when the method finishes.
-            file_conflict_resolver {FileConflictResolver} -- A function specifying how to deal
-                with overwriting or deleting files. The default always asks the user.
-        """
-        tmp_dir = self._tmp_dir.new_subdir()
-
-        if target is None:
-            PRETTY.starting_synchronizer("None", "IPD", url)
-            raise FatalException("Got 'None' as target directory, aborting")
-
-        if isinstance(target, Organizer):
-            organizer = target
+        crawlers: List[str]
+        if cli_crawlers is None:
+            log.explain("No crawlers specified on CLI")
+            log.explain("Running crawlers specified in config")
+            crawlers = self._find_config_crawlers(config)
         else:
-            organizer = Organizer(self.resolve(to_path(target)), file_conflict_resolver)
+            log.explain("Crawlers specified on CLI")
+            crawlers = self._find_cli_crawlers(config, cli_crawlers)
 
-        PRETTY.starting_synchronizer(organizer.path, "IPD", url)
+        skips = {f"crawl:{name}" for name in cli_skips} if cli_skips else set()
+        for crawler in crawlers:
+            if crawler in skips:
+                log.explain(f"Skipping crawler {crawler!r}")
+        crawlers = [crawler for crawler in crawlers if crawler not in skips]
 
-        elements: List[IpdDownloadInfo] = IpdCrawler(url).crawl()
-        transformed = apply_transform(transform, elements)
+        return crawlers
 
-        if self._test_run:
-            self._print_transformables(transformed)
-            return organizer
+    def _load_authenticators(self) -> None:
+        for name, section in self._config.auth_sections():
+            log.print(f"[bold bright_cyan]Loading[/] {escape(name)}")
 
-        downloader = IpdDownloader(tmp_dir=tmp_dir, organizer=organizer, strategy=download_strategy)
-        downloader.download_all(transformed)
+            auth_type = AuthSection(section).type()
+            authenticator_constructor = AUTHENTICATORS.get(auth_type)
+            if authenticator_constructor is None:
+                raise ConfigOptionError(name, "type", f"Unknown authenticator type: {auth_type!r}")
 
-        if clean:
-            organizer.cleanup()
+            authenticator = authenticator_constructor(name, section, self._config)
+            self._authenticators[name] = authenticator
 
-        self._download_summary.merge(organizer.download_summary)
+    def _load_crawlers(self) -> None:
+        # Cookie sharing
+        kit_ilias_web_paths: Dict[Authenticator, List[Path]] = {}
 
-        return organizer
+        for name, section in self._config.crawl_sections():
+            log.print(f"[bold bright_cyan]Loading[/] {escape(name)}")
 
-    @swallow_and_print_errors
-    def diva_kit(
-            self,
-            target: Union[PathLike, Organizer],
-            playlist_location: str,
-            transform: Transform = lambda x: x,
-            download_strategy: DivaDownloadStrategy = diva_download_new,
-            clean: bool = True,
-            file_conflict_resolver: FileConflictResolver = resolve_prompt_user
-    ) -> Organizer:
+            crawl_type = CrawlerSection(section).type()
+            crawler_constructor = CRAWLERS.get(crawl_type)
+            if crawler_constructor is None:
+                raise ConfigOptionError(name, "type", f"Unknown crawler type: {crawl_type!r}")
+
+            crawler = crawler_constructor(name, section, self._config, self._authenticators)
+            self._crawlers[name] = crawler
+
+            if self._config.default_section.share_cookies():
+                if isinstance(crawler, KitIliasWebCrawler):
+                    crawler.share_cookies(kit_ilias_web_paths)
+
+    def debug_transforms(self) -> None:
+        for name in self._crawlers_to_run:
+            crawler = self._crawlers[name]
+            log.print("")
+            log.print(f"[bold bright_cyan]Debugging transforms[/] for {escape(name)}")
+            crawler.debug_transforms()
+
+    async def run(self, debug_transforms: bool) -> None:
         """
-        Synchronizes a folder with a DIVA playlist.
-
-        Arguments:
-            organizer {Organizer} -- The organizer to use.
-            playlist_location {str} -- the playlist id or the playlist URL
-              in the format 'https://mediaservice.bibliothek.kit.edu/#/details/DIVA-2019-271'
-
-        Keyword Arguments:
-            transform {Transform} -- A transformation function for the output paths. Return None
-                to ignore a file. (default: {lambdax:x})
-            download_strategy {DivaDownloadStrategy} -- A function to determine which files need to
-                be downloaded. Can save bandwidth and reduce the number of requests.
-                (default: {diva_download_new})
-            clean {bool} -- Whether to clean up when the method finishes.
-            file_conflict_resolver {FileConflictResolver} -- A function specifying how to deal
-                with overwriting or deleting files. The default always asks the user.
+        May throw ConfigOptionError.
         """
-        tmp_dir = self._tmp_dir.new_subdir()
 
-        if playlist_location.startswith("http"):
-            playlist_id = DivaPlaylistCrawler.fetch_id(playlist_link=playlist_location)
-        else:
-            playlist_id = playlist_location
+        # These two functions must run inside the same event loop as the
+        # crawlers, so that any new objects (like Conditions or Futures) can
+        # obtain the correct event loop.
+        self._load_authenticators()
+        self._load_crawlers()
 
-        if target is None:
-            PRETTY.starting_synchronizer("None", "DIVA", playlist_id)
-            raise FatalException("Got 'None' as target directory, aborting")
+        if debug_transforms:
+            log.output_explain = True
+            log.output_report = False
+            self.debug_transforms()
+            return
 
-        if isinstance(target, Organizer):
-            organizer = target
-        else:
-            organizer = Organizer(self.resolve(to_path(target)), file_conflict_resolver)
+        log.print("")
 
-        PRETTY.starting_synchronizer(organizer.path, "DIVA", playlist_id)
+        for name in self._crawlers_to_run:
+            crawler = self._crawlers[name]
 
-        crawler = DivaPlaylistCrawler(playlist_id)
-        downloader = DivaDownloader(tmp_dir, organizer, download_strategy)
+            log.print(f"[bold bright_cyan]Running[/] {escape(name)}")
 
-        info = crawler.crawl()
+            try:
+                await crawler.run()
+            except (CrawlError, AuthError) as e:
+                log.error(str(e))
+            except Exception:
+                log.unexpected_exception()
 
-        transformed = apply_transform(transform, info)
-        if self._test_run:
-            self._print_transformables(transformed)
-            return organizer
+    def print_report(self) -> None:
+        for name in self._crawlers_to_run:
+            crawler = self._crawlers.get(name)
+            if crawler is None:
+                continue  # Crawler failed to load
 
-        downloader.download_all(transformed)
+            log.report("")
+            log.report(f"[bold bright_cyan]Report[/] for {escape(name)}")
 
-        if clean:
-            organizer.cleanup()
+            something_changed = False
+            for path in sorted(crawler.report.added_files):
+                something_changed = True
+                log.report(f"  [bold bright_green]Added[/] {fmt_path(path)}")
+            for path in sorted(crawler.report.changed_files):
+                something_changed = True
+                log.report(f"  [bold bright_yellow]Changed[/] {fmt_path(path)}")
+            for path in sorted(crawler.report.deleted_files):
+                something_changed = True
+                log.report(f"  [bold bright_magenta]Deleted[/] {fmt_path(path)}")
+            for path in sorted(crawler.report.not_deleted_files):
+                something_changed = True
+                log.report_not_deleted(f"  [bold bright_magenta]Not deleted[/] {fmt_path(path)}")
 
-        self._download_summary.merge(organizer.download_summary)
+            for warning in crawler.report.encountered_warnings:
+                something_changed = True
+                log.report(f"  [bold bright_red]Warning[/] {warning}")
 
-        return organizer
+            for error in crawler.report.encountered_errors:
+                something_changed = True
+                log.report(f"  [bold bright_red]Error[/] {error}")
+
+            if not something_changed:
+                log.report("  Nothing changed")

PFERD/progress.py

@@ -1,111 +0,0 @@
-"""
-A small progress bar implementation.
-"""
-import sys
-from dataclasses import dataclass
-from types import TracebackType
-from typing import Optional, Type
-
-import requests
-from rich.console import Console
-from rich.progress import (BarColumn, DownloadColumn, Progress, TaskID,
-                           TextColumn, TimeRemainingColumn,
-                           TransferSpeedColumn)
-
-_progress: Progress = Progress(
-    TextColumn("[bold blue]{task.fields[name]}", justify="right"),
-    BarColumn(bar_width=None),
-    "[progress.percentage]{task.percentage:>3.1f}%",
-    "•",
-    DownloadColumn(),
-    "•",
-    TransferSpeedColumn(),
-    "•",
-    TimeRemainingColumn(),
-    console=Console(file=sys.stdout),
-    transient=True
-)
-
-
-def size_from_headers(response: requests.Response) -> Optional[int]:
-    """
-    Return the size of the download based on the response headers.
-
-    Arguments:
-        response {requests.Response} -- the response
-
-    Returns:
-        Optional[int] -- the size
-    """
-    if "Content-Length" in response.headers:
-        return int(response.headers["Content-Length"])
-    return None
-
-
-@dataclass
-class ProgressSettings:
-    """
-    Settings you can pass to customize the progress bar.
-    """
-    name: str
-    max_size: int
-
-
-def progress_for(settings: Optional[ProgressSettings]) -> 'ProgressContextManager':
-    """
-    Returns a context manager that displays progress
-
-    Returns:
-        ProgressContextManager -- the progress manager
-    """
-    return ProgressContextManager(settings)
-
-
-class ProgressContextManager:
-    """
-    A context manager used for displaying progress.
-    """
-
-    def __init__(self, settings: Optional[ProgressSettings]):
-        self._settings = settings
-        self._task_id: Optional[TaskID] = None
-
-    def __enter__(self) -> 'ProgressContextManager':
-        """Context manager entry function."""
-        if not self._settings:
-            return self
-
-        _progress.start()
-        self._task_id = _progress.add_task(
-            self._settings.name,
-            total=self._settings.max_size,
-            name=self._settings.name
-        )
-        return self
-
-    # pylint: disable=useless-return
-    def __exit__(
-            self,
-            exc_type: Optional[Type[BaseException]],
-            exc_value: Optional[BaseException],
-            traceback: Optional[TracebackType],
-    ) -> Optional[bool]:
-        """Context manager exit function. Removes the task."""
-        if self._task_id is None:
-            return None
-
-        _progress.remove_task(self._task_id)
-
-        if len(_progress.task_ids) == 0:
-            # We need to clean up after ourselves, as we were the last one
-            _progress.stop()
-            _progress.refresh()
-
-        return None
-
-    def advance(self, amount: float) -> None:
-        """
-        Advances the progress bar.
-        """
-        if self._task_id is not None:
-            _progress.advance(self._task_id, amount)

PFERD/report.py

@@ -0,0 +1,238 @@
+import json
+from pathlib import Path, PurePath
+from typing import Any, Dict, List, Optional, Set
+
+
+class ReportLoadError(Exception):
+    pass
+
+
+class MarkDuplicateError(Exception):
+    """
+    Tried to mark a file that was already marked.
+    """
+
+    def __init__(self, path: PurePath):
+        super().__init__(f"A previous file already used path {path}")
+        self.path = path
+
+
+class MarkConflictError(Exception):
+    """
+    Marking the path would have caused a conflict.
+
+    A conflict can have two reasons: Either the new file has the same path as
+    the parent directory of a known file, or a parent directory of the new file
+    has the same path as a known file. In either case, adding the new file
+    would require a file and a directory to share the same path, which is
+    usually not possible.
+    """
+
+    def __init__(self, path: PurePath, collides_with: PurePath):
+        super().__init__(f"File at {path} collides with previous file at {collides_with}")
+        self.path = path
+        self.collides_with = collides_with
+
+
+# TODO Use PurePath.is_relative_to when updating to 3.9
+def is_relative_to(a: PurePath, b: PurePath) -> bool:
+    try:
+        a.relative_to(b)
+        return True
+    except ValueError:
+        return False
+
+
+class Report:
+    """
+    A report of a synchronization. Includes all files found by the crawler, as
+    well as the set of changes made to local files.
+    """
+
+    def __init__(self) -> None:
+        # Paths found by the crawler, untransformed
+        self.found_paths: Set[PurePath] = set()
+
+        # Files reserved for metadata files (e. g. the report file or cookies)
+        # that can't be overwritten by user transforms and won't be cleaned up
+        # at the end.
+        self.reserved_files: Set[PurePath] = set()
+
+        # Files found by the crawler, transformed. Only includes files that
+        # were downloaded (or a download was attempted)
+        self.known_files: Set[PurePath] = set()
+
+        self.added_files: Set[PurePath] = set()
+        self.changed_files: Set[PurePath] = set()
+        self.deleted_files: Set[PurePath] = set()
+        # Files that should have been deleted by the cleanup but weren't
+        self.not_deleted_files: Set[PurePath] = set()
+
+        # Custom crawler-specific data
+        self.custom: Dict[str, Any] = dict()
+
+        # Encountered errors and warnings
+        self.encountered_warnings: List[str] = []
+        self.encountered_errors: List[str] = []
+
+    @staticmethod
+    def _get_list_of_strs(data: Dict[str, Any], key: str) -> List[str]:
+        result: Any = data.get(key, [])
+
+        if not isinstance(result, list):
+            raise ReportLoadError(f"Incorrect format: {key!r} is not a list")
+
+        for elem in result:
+            if not isinstance(elem, str):
+                raise ReportLoadError(f"Incorrect format: {key!r} must contain only strings")
+
+        return result
+
+    @staticmethod
+    def _get_str_dictionary(data: Dict[str, Any], key: str) -> Dict[str, Any]:
+        result: Dict[str, Any] = data.get(key, {})
+
+        if not isinstance(result, dict):
+            raise ReportLoadError(f"Incorrect format: {key!r} is not a dictionary")
+
+        return result
+
+    @classmethod
+    def load(cls, path: Path) -> "Report":
+        """
+        May raise OSError, UnicodeDecodeError, JsonDecodeError, ReportLoadError.
+        """
+
+        with open(path, encoding="utf-8") as f:
+            data = json.load(f)
+
+        if not isinstance(data, dict):
+            raise ReportLoadError("Incorrect format: Root is not an object")
+
+        self = cls()
+        for elem in self._get_list_of_strs(data, "found"):
+            self.found(PurePath(elem))
+        for elem in self._get_list_of_strs(data, "reserved"):
+            self.mark_reserved(PurePath(elem))
+        for elem in self._get_list_of_strs(data, "known"):
+            self.mark(PurePath(elem))
+        for elem in self._get_list_of_strs(data, "added"):
+            self.add_file(PurePath(elem))
+        for elem in self._get_list_of_strs(data, "changed"):
+            self.change_file(PurePath(elem))
+        for elem in self._get_list_of_strs(data, "deleted"):
+            self.delete_file(PurePath(elem))
+        for elem in self._get_list_of_strs(data, "not_deleted"):
+            self.not_delete_file(PurePath(elem))
+        self.custom = self._get_str_dictionary(data, "custom")
+        self.encountered_errors = self._get_list_of_strs(data, "encountered_errors")
+        self.encountered_warnings = self._get_list_of_strs(data, "encountered_warnings")
+
+        return self
+
+    def store(self, path: Path) -> None:
+        """
+        May raise OSError.
+        """
+
+        data = {
+            "found": [str(path) for path in sorted(self.found_paths)],
+            "reserved": [str(path) for path in sorted(self.reserved_files)],
+            "known": [str(path) for path in sorted(self.known_files)],
+            "added": [str(path) for path in sorted(self.added_files)],
+            "changed": [str(path) for path in sorted(self.changed_files)],
+            "deleted": [str(path) for path in sorted(self.deleted_files)],
+            "not_deleted": [str(path) for path in sorted(self.not_deleted_files)],
+            "custom": self.custom,
+            "encountered_warnings": self.encountered_warnings,
+            "encountered_errors": self.encountered_errors,
+        }
+
+        with open(path, "w", encoding="utf-8") as f:
+            json.dump(data, f, indent=2, sort_keys=True)
+            f.write("\n")  # json.dump doesn't do this
+
+    def found(self, path: PurePath) -> None:
+        self.found_paths.add(path)
+
+    def mark_reserved(self, path: PurePath) -> None:
+        if path in self.marked:
+            raise RuntimeError("Trying to reserve an already reserved file")
+
+        self.reserved_files.add(path)
+
+    def mark(self, path: PurePath) -> None:
+        """
+        Mark a previously unknown file as known.
+
+        May throw a MarkDuplicateError or a MarkConflictError. For more detail,
+        see the respective exception's docstring.
+        """
+
+        for other in self.marked:
+            if path == other:
+                raise MarkDuplicateError(path)
+
+            if is_relative_to(path, other) or is_relative_to(other, path):
+                raise MarkConflictError(path, other)
+
+        self.known_files.add(path)
+
+    @property
+    def marked(self) -> Set[PurePath]:
+        return self.known_files | self.reserved_files
+
+    def is_marked(self, path: PurePath) -> bool:
+        return path in self.marked
+
+    def add_file(self, path: PurePath) -> None:
+        """
+        Unlike mark(), this function accepts any paths.
+        """
+
+        self.added_files.add(path)
+
+    def change_file(self, path: PurePath) -> None:
+        """
+        Unlike mark(), this function accepts any paths.
+        """
+
+        self.changed_files.add(path)
+
+    def delete_file(self, path: PurePath) -> None:
+        """
+        Unlike mark(), this function accepts any paths.
+        """
+
+        self.deleted_files.add(path)
+
+    def not_delete_file(self, path: PurePath) -> None:
+        """
+        Unlike mark(), this function accepts any paths.
+        """
+
+        self.not_deleted_files.add(path)
+
+    def add_custom_value(self, key: str, value: Any) -> None:
+        """
+        Adds a custom value under the passed key, overwriting any existing
+        """
+        self.custom[key] = value
+
+    def get_custom_value(self, key: str) -> Optional[Any]:
+        """
+        Retrieves a custom value for the given key.
+        """
+        return self.custom.get(key)
+
+    def add_error(self, error: str) -> None:
+        """
+        Adds an error to this report's error list.
+        """
+        self.encountered_errors.append(error)
+
+    def add_warning(self, warning: str) -> None:
+        """
+        Adds a warning to this report's warning list.
+        """
+        self.encountered_warnings.append(warning)

PFERD/tmp_dir.py

@@ -1,79 +0,0 @@
-"""Helper functions and classes for temporary folders."""
-
-import logging
-import shutil
-from pathlib import Path
-from types import TracebackType
-from typing import Optional, Type
-
-from .location import Location
-
-LOGGER = logging.getLogger(__name__)
-
-
-class TmpDir(Location):
-    """A temporary folder that can create files or nested temp folders."""
-
-    def __init__(self, path: Path):
-        """Create a new temporary folder for the given path."""
-        super().__init__(path)
-        self._counter = 0
-        self.cleanup()
-        self.path.mkdir(parents=True, exist_ok=True)
-
-    def __str__(self) -> str:
-        """Format the folder as a string."""
-        return f"Folder at {self.path}"
-
-    def __enter__(self) -> 'TmpDir':
-        """Context manager entry function."""
-        return self
-
-    # pylint: disable=useless-return
-    def __exit__(
-            self,
-            exc_type: Optional[Type[BaseException]],
-            exc_value: Optional[BaseException],
-            traceback: Optional[TracebackType],
-    ) -> Optional[bool]:
-        """Context manager exit function. Calls cleanup()."""
-        self.cleanup()
-        return None
-
-    def new_path(self, prefix: Optional[str] = None) -> Path:
-        """
-        Return a unique path inside the directory. Doesn't create a file or
-        directory.
-        """
-
-        name = f"{prefix if prefix else 'tmp'}-{self._inc_and_get_counter():03}"
-
-        LOGGER.debug("Creating temp file %s", name)
-
-        return self.resolve(Path(name))
-
-    def new_subdir(self, prefix: Optional[str] = None) -> 'TmpDir':
-        """
-        Create a new nested temporary folder and return it.
-        """
-
-        name = f"{prefix if prefix else 'tmp'}-{self._inc_and_get_counter():03}"
-        sub_path = self.resolve(Path(name))
-        sub_path.mkdir(parents=True)
-
-        LOGGER.debug("Creating temp dir %s at %s", name, sub_path)
-
-        return TmpDir(sub_path)
-
-    def cleanup(self) -> None:
-        """Delete this folder and all contained files."""
-        LOGGER.debug("Deleting temp folder %s", self.path)
-
-        if self.path.resolve().exists():
-            shutil.rmtree(self.path.resolve())
-
-    def _inc_and_get_counter(self) -> int:
-        """Get and increment the counter by one."""
-        counter = self._counter
-        self._counter += 1
-        return counter

PFERD/transform.py

@@ -1,142 +0,0 @@
-"""
-Transforms let the user define functions to decide where the downloaded files
-should be placed locally. They let the user do more advanced things like moving
-only files whose names match a regex, or renaming files from one numbering
-scheme to another.
-"""
-
-import os
-import re
-from dataclasses import dataclass
-from pathlib import PurePath
-from typing import Callable, List, Optional, TypeVar
-
-from .utils import PathLike, Regex, to_path, to_pattern
-
-Transform = Callable[[PurePath], Optional[PurePath]]
-
-
-@dataclass
-class Transformable:
-    """
-    An object that can be transformed by a Transform.
-    """
-
-    path: PurePath
-
-
-TF = TypeVar("TF", bound=Transformable)
-
-
-def apply_transform(
-        transform: Transform,
-        transformables: List[TF],
-) -> List[TF]:
-    """
-    Apply a Transform to multiple Transformables, discarding those that were
-    not transformed by the Transform.
-    """
-
-    result: List[TF] = []
-    for transformable in transformables:
-        new_path = transform(transformable.path)
-        if new_path:
-            transformable.path = new_path
-            result.append(transformable)
-    return result
-
-# Transform combinators
-
-def keep(path: PurePath) -> Optional[PurePath]:
-    return path
-
-def attempt(*args: Transform) -> Transform:
-    def inner(path: PurePath) -> Optional[PurePath]:
-        for transform in args:
-            result = transform(path)
-            if result:
-                return result
-        return None
-    return inner
-
-def optionally(transform: Transform) -> Transform:
-    return attempt(transform, lambda path: path)
-
-def do(*args: Transform) -> Transform:
-    def inner(path: PurePath) -> Optional[PurePath]:
-        current = path
-        for transform in args:
-            result = transform(current)
-            if result:
-                current = result
-            else:
-                return None
-        return current
-    return inner
-
-def predicate(pred: Callable[[PurePath], bool]) -> Transform:
-    def inner(path: PurePath) -> Optional[PurePath]:
-        if pred(path):
-            return path
-        return None
-    return inner
-
-def glob(pattern: str) -> Transform:
-    return predicate(lambda path: path.match(pattern))
-
-def move_dir(source_dir: PathLike, target_dir: PathLike) -> Transform:
-    source_path = to_path(source_dir)
-    target_path = to_path(target_dir)
-    def inner(path: PurePath) -> Optional[PurePath]:
-        if source_path in path.parents:
-            return target_path / path.relative_to(source_path)
-        return None
-    return inner
-
-def move(source: PathLike, target: PathLike) -> Transform:
-    source_path = to_path(source)
-    target_path = to_path(target)
-    def inner(path: PurePath) -> Optional[PurePath]:
-        if path == source_path:
-            return target_path
-        return None
-    return inner
-
-def rename(source: str, target: str) -> Transform:
-    def inner(path: PurePath) -> Optional[PurePath]:
-        if path.name == source:
-            return path.with_name(target)
-        return None
-    return inner
-
-def re_move(regex: Regex, target: str) -> Transform:
-    def inner(path: PurePath) -> Optional[PurePath]:
-        match = to_pattern(regex).fullmatch(str(path))
-        if match:
-            groups = [match.group(0)]
-            groups.extend(match.groups())
-            return PurePath(target.format(*groups))
-        return None
-    return inner
-
-def re_rename(regex: Regex, target: str) -> Transform:
-    def inner(path: PurePath) -> Optional[PurePath]:
-        match = to_pattern(regex).fullmatch(path.name)
-        if match:
-            groups = [match.group(0)]
-            groups.extend(match.groups())
-            return path.with_name(target.format(*groups))
-        return None
-    return inner
-
-
-def sanitize_windows_path(path: PurePath) -> Optional[PurePath]:
-    """
-    A small function to escape characters that are forbidden in windows path names.
-    This method is a no-op on other operating systems.
-    """
-    # Escape windows illegal path characters
-    if os.name == 'nt':
-        sanitized_parts = [re.sub(r'[<>:"/|?]', "_", x) for x in list(path.parts)]
-        return PurePath(*sanitized_parts)
-    return path

PFERD/transformer.py

@@ -0,0 +1,439 @@
+import ast
+import re
+from abc import ABC, abstractmethod
+from dataclasses import dataclass
+from enum import Enum
+from pathlib import PurePath
+from typing import Callable, Dict, List, Optional, Sequence, TypeVar, Union
+
+from .logging import log
+from .utils import fmt_path, str_path
+
+
+class ArrowHead(Enum):
+    NORMAL = 0
+    SEQUENCE = 1
+
+
+class Ignore:
+    pass
+
+
+class Empty:
+    pass
+
+
+RightSide = Union[str, Ignore, Empty]
+
+
+@dataclass
+class Transformed:
+    path: PurePath
+
+
+class Ignored:
+    pass
+
+
+TransformResult = Optional[Union[Transformed, Ignored]]
+
+
+@dataclass
+class Rule:
+    left: str
+    left_index: int
+    name: str
+    head: ArrowHead
+    right: RightSide
+    right_index: int
+
+    def right_result(self, path: PurePath) -> Union[str, Transformed, Ignored]:
+        if isinstance(self.right, str):
+            return self.right
+        elif isinstance(self.right, Ignore):
+            return Ignored()
+        elif isinstance(self.right, Empty):
+            return Transformed(path)
+        else:
+            raise RuntimeError(f"Right side has invalid type {type(self.right)}")
+
+
+class Transformation(ABC):
+    def __init__(self, rule: Rule):
+        self.rule = rule
+
+    @abstractmethod
+    def transform(self, path: PurePath) -> TransformResult:
+        pass
+
+
+class ExactTf(Transformation):
+    def transform(self, path: PurePath) -> TransformResult:
+        if path != PurePath(self.rule.left):
+            return None
+
+        right = self.rule.right_result(path)
+        if not isinstance(right, str):
+            return right
+
+        return Transformed(PurePath(right))
+
+
+class ExactReTf(Transformation):
+    def transform(self, path: PurePath) -> TransformResult:
+        match = re.fullmatch(self.rule.left, str_path(path))
+        if not match:
+            return None
+
+        right = self.rule.right_result(path)
+        if not isinstance(right, str):
+            return right
+
+        # For some reason, mypy thinks that "groups" has type List[str]. But
+        # since elements of "match.groups()" can be None, mypy is wrong.
+        groups: Sequence[Optional[str]] = [match[0]] + list(match.groups())
+
+        locals_dir: Dict[str, Union[str, int, float]] = {}
+        for i, group in enumerate(groups):
+            if group is None:
+                continue
+
+            locals_dir[f"g{i}"] = group
+
+            try:
+                locals_dir[f"i{i}"] = int(group)
+            except ValueError:
+                pass
+
+            try:
+                locals_dir[f"f{i}"] = float(group)
+            except ValueError:
+                pass
+
+        result = eval(f"f{right!r}", {}, locals_dir)
+        return Transformed(PurePath(result))
+
+
+class RenamingParentsTf(Transformation):
+    def __init__(self, sub_tf: Transformation):
+        super().__init__(sub_tf.rule)
+        self.sub_tf = sub_tf
+
+    def transform(self, path: PurePath) -> TransformResult:
+        for i in range(len(path.parts), -1, -1):
+            parent = PurePath(*path.parts[:i])
+            child = PurePath(*path.parts[i:])
+
+            transformed = self.sub_tf.transform(parent)
+            if not transformed:
+                continue
+            elif isinstance(transformed, Transformed):
+                return Transformed(transformed.path / child)
+            elif isinstance(transformed, Ignored):
+                return transformed
+            else:
+                raise RuntimeError(f"Invalid transform result of type {type(transformed)}: {transformed}")
+
+        return None
+
+
+class RenamingPartsTf(Transformation):
+    def __init__(self, sub_tf: Transformation):
+        super().__init__(sub_tf.rule)
+        self.sub_tf = sub_tf
+
+    def transform(self, path: PurePath) -> TransformResult:
+        result = PurePath()
+        any_part_matched = False
+        for part in path.parts:
+            transformed = self.sub_tf.transform(PurePath(part))
+            if not transformed:
+                result /= part
+            elif isinstance(transformed, Transformed):
+                result /= transformed.path
+                any_part_matched = True
+            elif isinstance(transformed, Ignored):
+                return transformed
+            else:
+                raise RuntimeError(f"Invalid transform result of type {type(transformed)}: {transformed}")
+
+        if any_part_matched:
+            return Transformed(result)
+        else:
+            return None
+
+
+class RuleParseError(Exception):
+    def __init__(self, line: "Line", reason: str):
+        super().__init__(f"Error in rule on line {line.line_nr}, column {line.index}: {reason}")
+
+        self.line = line
+        self.reason = reason
+
+    def pretty_print(self) -> None:
+        log.error(f"Error parsing rule on line {self.line.line_nr}:")
+        log.error_contd(self.line.line)
+        spaces = " " * self.line.index
+        log.error_contd(f"{spaces}^--- {self.reason}")
+
+
+T = TypeVar("T")
+
+
+class Line:
+    def __init__(self, line: str, line_nr: int):
+        self._line = line
+        self._line_nr = line_nr
+        self._index = 0
+
+    @property
+    def line(self) -> str:
+        return self._line
+
+    @property
+    def line_nr(self) -> int:
+        return self._line_nr
+
+    @property
+    def index(self) -> int:
+        return self._index
+
+    @index.setter
+    def index(self, index: int) -> None:
+        self._index = index
+
+    @property
+    def rest(self) -> str:
+        return self.line[self.index:]
+
+    def peek(self, amount: int = 1) -> str:
+        return self.rest[:amount]
+
+    def take(self, amount: int = 1) -> str:
+        string = self.peek(amount)
+        self.index += len(string)
+        return string
+
+    def expect(self, string: str) -> str:
+        if self.peek(len(string)) == string:
+            return self.take(len(string))
+        else:
+            raise RuleParseError(self, f"Expected {string!r}")
+
+    def expect_with(self, string: str, value: T) -> T:
+        self.expect(string)
+        return value
+
+    def one_of(self, parsers: List[Callable[[], T]], description: str) -> T:
+        for parser in parsers:
+            index = self.index
+            try:
+                return parser()
+            except RuleParseError:
+                self.index = index
+
+        raise RuleParseError(self, description)
+
+
+# RULE = LEFT SPACE '-' NAME '-' HEAD (SPACE RIGHT)?
+# SPACE = ' '+
+# NAME = '' | 'exact' | 'name' | 're' | 'exact-re' | 'name-re'
+# HEAD = '>' | '>>'
+# LEFT = STR | QUOTED_STR
+# RIGHT = STR | QUOTED_STR | '!'
+
+
+def parse_zero_or_more_spaces(line: Line) -> None:
+    while line.peek() == " ":
+        line.take()
+
+
+def parse_one_or_more_spaces(line: Line) -> None:
+    line.expect(" ")
+    parse_zero_or_more_spaces(line)
+
+
+def parse_str(line: Line) -> str:
+    result = []
+    while c := line.peek():
+        if c == " ":
+            break
+        else:
+            line.take()
+            result.append(c)
+
+    if result:
+        return "".join(result)
+    else:
+        raise RuleParseError(line, "Expected non-space character")
+
+
+QUOTATION_MARKS = {'"', "'"}
+
+
+def parse_quoted_str(line: Line) -> str:
+    escaped = False
+
+    # Points to first character of string literal
+    start_index = line.index
+
+    quotation_mark = line.peek()
+    if quotation_mark not in QUOTATION_MARKS:
+        raise RuleParseError(line, "Expected quotation mark")
+    line.take()
+
+    while c := line.peek():
+        if escaped:
+            escaped = False
+            line.take()
+        elif c == quotation_mark:
+            line.take()
+            stop_index = line.index
+            literal = line.line[start_index:stop_index]
+            try:
+                return ast.literal_eval(literal)
+            except SyntaxError as e:
+                line.index = start_index
+                raise RuleParseError(line, str(e)) from e
+        elif c == "\\":
+            escaped = True
+            line.take()
+        else:
+            line.take()
+
+    raise RuleParseError(line, "Expected end of string literal")
+
+
+def parse_left(line: Line) -> str:
+    if line.peek() in QUOTATION_MARKS:
+        return parse_quoted_str(line)
+    else:
+        return parse_str(line)
+
+
+def parse_right(line: Line) -> Union[str, Ignore]:
+    c = line.peek()
+    if c in QUOTATION_MARKS:
+        return parse_quoted_str(line)
+    else:
+        string = parse_str(line)
+        if string == "!":
+            return Ignore()
+        return string
+
+
+def parse_arrow_name(line: Line) -> str:
+    return line.one_of([
+        lambda: line.expect("exact-re"),
+        lambda: line.expect("exact"),
+        lambda: line.expect("name-re"),
+        lambda: line.expect("name"),
+        lambda: line.expect("re"),
+        lambda: line.expect(""),
+    ], "Expected arrow name")
+
+
+def parse_arrow_head(line: Line) -> ArrowHead:
+    return line.one_of([
+        lambda: line.expect_with(">>", ArrowHead.SEQUENCE),
+        lambda: line.expect_with(">", ArrowHead.NORMAL),
+    ], "Expected arrow head")
+
+
+def parse_eol(line: Line) -> None:
+    if line.peek():
+        raise RuleParseError(line, "Expected end of line")
+
+
+def parse_rule(line: Line) -> Rule:
+    parse_zero_or_more_spaces(line)
+    left_index = line.index
+    left = parse_left(line)
+
+    parse_one_or_more_spaces(line)
+
+    line.expect("-")
+    name = parse_arrow_name(line)
+    line.expect("-")
+    head = parse_arrow_head(line)
+
+    right_index = line.index
+    right: RightSide
+    try:
+        parse_zero_or_more_spaces(line)
+        parse_eol(line)
+        right = Empty()
+    except RuleParseError:
+        line.index = right_index
+        parse_one_or_more_spaces(line)
+        right = parse_right(line)
+        parse_eol(line)
+
+    return Rule(left, left_index, name, head, right, right_index)
+
+
+def parse_transformation(line: Line) -> Transformation:
+    rule = parse_rule(line)
+
+    if rule.name == "":
+        return RenamingParentsTf(ExactTf(rule))
+    elif rule.name == "exact":
+        return ExactTf(rule)
+    elif rule.name == "name":
+        if len(PurePath(rule.left).parts) > 1:
+            line.index = rule.left_index
+            raise RuleParseError(line, "Expected name, not multiple segments")
+        return RenamingPartsTf(ExactTf(rule))
+    elif rule.name == "re":
+        return RenamingParentsTf(ExactReTf(rule))
+    elif rule.name == "exact-re":
+        return ExactReTf(rule)
+    elif rule.name == "name-re":
+        return RenamingPartsTf(ExactReTf(rule))
+    else:
+        raise RuntimeError(f"Invalid arrow name {rule.name!r}")
+
+
+class Transformer:
+    def __init__(self, rules: str):
+        """
+        May throw a RuleParseException.
+        """
+
+        self._tfs = []
+        for i, line in enumerate(rules.split("\n")):
+            line = line.strip()
+            if line:
+                tf = parse_transformation(Line(line, i))
+                self._tfs.append((line, tf))
+
+    def transform(self, path: PurePath) -> Optional[PurePath]:
+        for i, (line, tf) in enumerate(self._tfs):
+            log.explain(f"Testing rule {i+1}: {line}")
+
+            try:
+                result = tf.transform(path)
+            except Exception as e:
+                log.warn(f"Error while testing rule {i+1}: {line}")
+                log.warn_contd(str(e))
+                continue
+
+            if not result:
+                continue
+
+            if isinstance(result, Ignored):
+                log.explain("Match found, path ignored")
+                return None
+
+            if tf.rule.head == ArrowHead.NORMAL:
+                log.explain(f"Match found, transformed path to {fmt_path(result.path)}")
+                path = result.path
+                break
+            elif tf.rule.head == ArrowHead.SEQUENCE:
+                log.explain(f"Match found, updated path to {fmt_path(result.path)}")
+                path = result.path
+            else:
+                raise RuntimeError(f"Invalid transform result of type {type(result)}: {result}")
+
+        log.explain(f"Final result: {fmt_path(path)}")
+        return path

PFERD/utils.py

@@ -1,98 +1,144 @@
-"""
-A few utility bobs and bits.
-"""
-
-import re
+import asyncio
+import getpass
+import sys
+import threading
+from abc import ABC, abstractmethod
+from contextlib import AsyncExitStack
 from pathlib import Path, PurePath
-from typing import Optional, Tuple, Union
+from types import TracebackType
+from typing import Any, Callable, Dict, Generic, Optional, Type, TypeVar
+from urllib.parse import parse_qs, urlencode, urlsplit, urlunsplit
 
 import bs4
-import requests
 
-from .progress import ProgressSettings, progress_for, size_from_headers
-
-PathLike = Union[PurePath, str, Tuple[str, ...]]
+T = TypeVar("T")
 
 
-def to_path(pathlike: PathLike) -> Path:
+async def in_daemon_thread(func: Callable[..., T], *args: Any, **kwargs: Any) -> T:
+    loop = asyncio.get_running_loop()
+    future: asyncio.Future[T] = asyncio.Future()
+
+    def thread_func() -> None:
+        result = func()
+        loop.call_soon_threadsafe(future.set_result, result)
+
+    threading.Thread(target=thread_func, daemon=True).start()
+
+    return await future
+
+
+async def ainput(prompt: str) -> str:
+    return await in_daemon_thread(lambda: input(prompt))
+
+
+async def agetpass(prompt: str) -> str:
+    return await in_daemon_thread(lambda: getpass.getpass(prompt))
+
+
+async def prompt_yes_no(query: str, default: Optional[bool]) -> bool:
     """
-    Convert a given PathLike into a Path.
-    """
-    if isinstance(pathlike, tuple):
-        return Path(*pathlike)
-    return Path(pathlike)
-
-
-Regex = Union[str, re.Pattern]
-
-
-def to_pattern(regex: Regex) -> re.Pattern:
-    """
-    Convert a regex to a re.Pattern.
-    """
-    if isinstance(regex, re.Pattern):
-        return regex
-    return re.compile(regex)
-
-
-def soupify(response: requests.Response) -> bs4.BeautifulSoup:
-    """
-    Wrap a requests response in a bs4 object.
-    """
-
-    return bs4.BeautifulSoup(response.text, "html.parser")
-
-
-def stream_to_path(
-        response: requests.Response,
-        target: Path,
-        progress_name: Optional[str] = None,
-        chunk_size: int = 1024 ** 2
-) -> None:
-    """
-    Download a requests response content to a file by streaming it. This
-    function avoids excessive memory usage when downloading large files. The
-    chunk_size is in bytes.
-
-    If progress_name is None, no progress bar will be shown. Otherwise a progress
-    bar will appear, if the download is bigger than an internal threshold.
-    """
-
-    with response:
-        length = size_from_headers(response)
-        if progress_name and length and int(length) > 1024 * 1024 * 10:  # 10 MiB
-            settings: Optional[ProgressSettings] = ProgressSettings(progress_name, length)
-        else:
-            settings = None
-
-        with open(target, 'wb') as file_descriptor:
-            with progress_for(settings) as progress:
-                for chunk in response.iter_content(chunk_size=chunk_size):
-                    file_descriptor.write(chunk)
-                    progress.advance(len(chunk))
-
-
-def prompt_yes_no(question: str, default: Optional[bool] = None) -> bool:
-    """
-    Prompts the user a yes/no question and returns their choice.
+    Asks the user a yes/no question and returns their choice.
     """
 
     if default is True:
-        prompt = "[Y/n]"
+        query += " [Y/n] "
     elif default is False:
-        prompt = "[y/N]"
+        query += " [y/N] "
     else:
-        prompt = "[y/n]"
-
-    text = f"{question} {prompt} "
-    wrong_reply = "Please reply with 'yes'/'y' or 'no'/'n'."
+        query += " [y/n] "
 
     while True:
-        response = input(text).strip().lower()
-        if response in {"yes", "ye", "y"}:
+        response = (await ainput(query)).strip().lower()
+        if response == "y":
             return True
-        if response in {"no", "n"}:
+        elif response == "n":
             return False
-        if response == "" and default is not None:
+        elif response == "" and default is not None:
             return default
-        print(wrong_reply)
+
+        print("Please answer with 'y' or 'n'.")
+
+
+def soupify(data: bytes) -> bs4.BeautifulSoup:
+    """
+    Parses HTML to a beautifulsoup object.
+    """
+
+    return bs4.BeautifulSoup(data, "html.parser")
+
+
+def url_set_query_param(url: str, param: str, value: str) -> str:
+    """
+    Set a query parameter in an url, overwriting existing ones with the same name.
+    """
+    scheme, netloc, path, query, fragment = urlsplit(url)
+    query_parameters = parse_qs(query)
+    query_parameters[param] = [value]
+    new_query_string = urlencode(query_parameters, doseq=True)
+
+    return urlunsplit((scheme, netloc, path, new_query_string, fragment))
+
+
+def url_set_query_params(url: str, params: Dict[str, str]) -> str:
+    """
+    Sets multiple query parameters in an url, overwriting existing ones.
+    """
+    result = url
+
+    for key, val in params.items():
+        result = url_set_query_param(result, key, val)
+
+    return result
+
+
+def str_path(path: PurePath) -> str:
+    if not path.parts:
+        return "."
+    return "/".join(path.parts)
+
+
+def fmt_path(path: PurePath) -> str:
+    return repr(str_path(path))
+
+
+def fmt_real_path(path: Path) -> str:
+    return repr(str(path.absolute()))
+
+
+class ReusableAsyncContextManager(ABC, Generic[T]):
+    def __init__(self) -> None:
+        self._active = False
+        self._stack = AsyncExitStack()
+
+    @abstractmethod
+    async def _on_aenter(self) -> T:
+        pass
+
+    async def __aenter__(self) -> T:
+        if self._active:
+            raise RuntimeError("Nested or otherwise concurrent usage is not allowed")
+
+        self._active = True
+        await self._stack.__aenter__()
+
+        # See https://stackoverflow.com/a/13075071
+        try:
+            result: T = await self._on_aenter()
+        except:  # noqa: E722 do not use bare 'except'
+            if not await self.__aexit__(*sys.exc_info()):
+                raise
+
+        return result
+
+    async def __aexit__(
+            self,
+            exc_type: Optional[Type[BaseException]],
+            exc_value: Optional[BaseException],
+            traceback: Optional[TracebackType],
+    ) -> Optional[bool]:
+        if not self._active:
+            raise RuntimeError("__aexit__ called too many times")
+
+        result = await self._stack.__aexit__(exc_type, exc_value, traceback)
+        self._active = False
+        return result

PFERD/version.py

@@ -0,0 +1,2 @@
+NAME = "PFERD"
+VERSION = "3.5.0"

README.md

@@ -2,254 +2,146 @@
 
 **P**rogramm zum **F**lotten, **E**infachen **R**unterladen von **D**ateien
 
-- [Quickstart with `sync_url`](#quickstart-with-sync_url)
-- [Installation](#installation)
-    - [Upgrading from 2.0.0 to 2.1.0+](#upgrading-from-200-to-210)
-- [Example setup](#example-setup)
-- [Usage](#usage)
-    - [General concepts](#general-concepts)
-    - [Constructing transforms](#constructing-transforms)
-        - [Transform creators](#transform-creators)
-        - [Transform combinators](#transform-combinators)
-    - [A short, but commented example](#a-short-but-commented-example)
+Other resources:
 
-## Quickstart with `sync_url`
-
-The `sync_url` program allows you to just synchronize a given ILIAS URL (of a
-course, a folder, your personal desktop, etc.) without any extra configuration
-or setting up. Download the program, open ILIAS, copy the URL from the address
-bar and pass it to sync_url.
-
-It bundles everything it needs in one executable and is easy to
-use, but doesn't expose all the configuration options and tweaks a full install
-does.
-
-1. Download the `sync_url` binary from the [latest release](https://github.com/Garmelon/PFERD/releases/latest).
-2. Recognize that you most likely need to enclose the URL in `""` quotes to prevent your shell from interpreting `&` and other symbols
-3. Run the binary in your terminal (`./sync_url` or `sync_url.exe` in the CMD) to see the help and use it. I'd recommend using the `--cookies` option.  
-  If you are on **Linux/Mac**, you need to *make the file executable* using `chmod +x <file>`.  
-  If you are on **Mac**, you need to allow this unverified program to run (see e.g. [here](https://www.switchingtomac.com/tutorials/osx/how-to-run-unverified-apps-on-macos/))
+- [Config file format](CONFIG.md)
+- [Changelog](CHANGELOG.md)
+- [Development Guide](DEV.md)
 
 ## Installation
 
-Ensure that you have at least Python 3.8 installed.
+### Direct download
+
+Binaries for Linux, Windows and Mac can be downloaded directly from the
+[latest release](https://github.com/Garmelon/PFERD/releases/latest).
+
+### With pip
+
+Ensure you have at least Python 3.9 installed. Run the following command to
+install PFERD or upgrade it to the latest version:
 
-To install PFERD or update your installation to the latest version, run this
-wherever you want to install or have already installed PFERD:
 ```
-$ pip install git+https://github.com/Garmelon/PFERD@v2.6.0
+$ pip install --upgrade git+https://github.com/Garmelon/PFERD@latest
 ```
 
-The use of [venv] is recommended.
+The use of [venv](https://docs.python.org/3/library/venv.html) is recommended.
 
-[venv]: https://docs.python.org/3/library/venv.html
+### With package managers
 
-### Upgrading from 2.0.0 to 2.1.0+
+Unofficial packages are available for:
+- [AUR](https://aur.archlinux.org/packages/pferd)
+- [brew](https://formulae.brew.sh/formula/pferd)
+- [conda-forge](https://github.com/conda-forge/pferd-feedstock)
+- [nixpkgs](https://github.com/NixOS/nixpkgs/blob/master/pkgs/tools/misc/pferd/default.nix)
+- [PyPi](https://pypi.org/project/pferd)
 
-- The `IliasDirectoryType` type was renamed to `IliasElementType` and is now far more detailed.
-  The new values are: `REGULAR_FOLDER`, `VIDEO_FOLDER`, `EXERCISE_FOLDER`, `REGULAR_FILE`, `VIDEO_FILE`, `FORUM`, `EXTERNAL_LINK`.
-- Forums and external links are skipped automatically if you use the `kit_ilias` helper.
+See also PFERD's [repology page](https://repology.org/project/pferd/versions).
 
-## Example setup
+## Basic usage
 
-In this example, `python3` refers to at least Python 3.8.
+PFERD can be run directly from the command line with no config file. Run `pferd
+-h` to get an overview of available commands and options. Run `pferd <command>
+-h` to see which options a command has.
+
+For example, you can download your personal desktop from the KIT ILIAS like
+this:
 
-A full example setup and initial use could look like:
 ```
-$ mkdir Vorlesungen
-$ cd Vorlesungen
-$ python3 -m venv .venv
-$ source .venv/bin/activate
-$ pip install git+https://github.com/Garmelon/PFERD@v2.6.0
-$ curl -O https://raw.githubusercontent.com/Garmelon/PFERD/v2.6.0/example_config.py
-$ python3 example_config.py
-$ deactivate
+$ pferd kit-ilias-web desktop <output_directory>
 ```
 
-Subsequent runs of the program might look like:
+Also, you can download most ILIAS pages directly like this:
+
 ```
-$ cd Vorlesungen
-$ source .venv/bin/activate
-$ python3 example_config.py
-$ deactivate
+$ pferd kit-ilias-web <url> <output_directory>
 ```
 
-If you just want to get started and crawl *your entire ILIAS Desktop* instead
-of a given set of courses, please replace `example_config.py` with
-`example_config_personal_desktop.py` in all of the instructions below (`curl` call and
-`python3` run command).
+However, the CLI only lets you download a single thing at a time, and the
+resulting command can grow long quite quickly. Because of this, PFERD can also
+be used with a config file.
 
-## Usage
+To get started, just take a command you've been using and add `--dump-config`
+directly after `pferd`, like this:
 
-### General concepts
-
-A PFERD config is a normal python file that starts multiple *synchronizers*
-which do all the heavy lifting. While you can create and wire them up manually,
-you are encouraged to use the helper methods provided in `PFERD.Pferd`.
-
-The synchronizers take some input arguments specific to their service and a
-*transform*. The transform receives the computed path of an element in ILIAS and
-can return either an output path (so you can rename files or move them around as
-you wish) or `None` if you do not want to save the given file.
-
-Additionally the ILIAS synchronizer allows you to define a *crawl filter*. This
-filter also receives the computed path as the input, but is only called for
-*directories*. If you return `True`, the directory will be crawled and
-searched. If you return `False` the directory will be ignored and nothing in it
-will be passed to the transform.
-
-### Constructing transforms
-
-While transforms are just normal python functions, writing them by hand can
-quickly become tedious. In order to help you with writing your own transforms
-and filters, PFERD defines a few useful transform creators and combinators in
-the `PFERD.transform` module:
-
-#### Transform creators
-
-These methods let you create a few basic transform building blocks:
-
-- **`glob(glob)`**  
-  Creates a transform that returns the unchanged path if the glob matches the path and `None` otherwise.
-  See also [Path.match].  
-  Example: `glob("Übung/*.pdf")`
-- **`predicate(pred)`**  
-  Creates a transform that returns the unchanged path if `pred(path)` returns a truthy value.
-  Returns `None` otherwise.  
-  Example: `predicate(lambda path: len(path.parts) == 3)`
-- **`move_dir(source, target)`**  
-  Creates a transform that moves all files from the `source` to the `target` directory.  
-  Example: `move_dir("Übung/", "Blätter/")`
-- **`move(source, target)`**  
-  Creates a transform that moves the `source` file to `target`.  
-  Example: `move("Vorlesung/VL02_Automten.pdf", "Vorlesung/VL02_Automaten.pdf")`
-- **`rename(source, target)`**  
-  Creates a transform that renames all files named `source` to `target`.
-  This transform works on the file names, not paths, and thus works no matter where the file is located.  
-  Example: `rename("VL02_Automten.pdf", "VL02_Automaten.pdf")`
-- **`re_move(regex, target)`**  
-  Creates a transform that moves all files matching `regex` to `target`.
-  The transform `str.format` on the `target` string with the contents of the capturing groups before returning it.
-  The capturing groups can be accessed via their index.
-  See also [Match.group].  
-  Example: `re_move(r"Übung/Blatt (\d+)\.pdf", "Blätter/Blatt_{1:0>2}.pdf")`
-- **`re_rename(regex, target)`**  
-  Creates a transform that renames all files matching `regex` to `target`.
-  This transform works on the file names, not paths, and thus works no matter where the file is located.  
-  Example: `re_rename(r"VL(\d+)(.*)\.pdf", "Vorlesung_Nr_{1}__{2}.pdf")`
-
-All movement or rename transforms above return `None` if a file doesn't match
-their movement or renaming criteria. This enables them to be used as building
-blocks to build up more complex transforms.
-
-In addition, `PFERD.transform` also defines the `keep` transform which returns its input path unchanged.
-This behaviour can be very useful when creating more complex transforms.
-See below for example usage.
-
-[Path.match]: https://docs.python.org/3/library/pathlib.html#pathlib.Path.match
-[Match.group]: https://docs.python.org/3/library/re.html#re.Match.group
-
-#### Transform combinators
-
-These methods let you combine transforms into more complex transforms:
-
-- **`optionally(transform)`**  
-  Wraps a given transform and returns its result if it is not `None`.
-  Otherwise returns the input path unchanged.
-  See below for example usage.
-* **`do(transforms)`**  
-  Accepts a series of transforms and applies them in the given order to the result of the previous one.
-  If any transform returns `None`, `do` short-circuits and also returns `None`.
-  This can be used to perform multiple renames in a row:
-  ```py
-  do(
-      # Move them
-      move_dir("Vorlesungsmaterial/Vorlesungsvideos/", "Vorlesung/Videos/"),
-      # Fix extensions (if they have any)
-      optionally(re_rename("(.*).m4v.mp4", "{1}.mp4")),
-      # Remove the 'dbs' prefix (if they have any)
-      optionally(re_rename("(?i)dbs-(.+)", "{1}")),
-  )
-  ```
-- **`attempt(transforms)`**  
-  Applies the passed transforms in the given order until it finds one that does not return `None`.
-  If it does not find any, it returns `None`.
-  This can be used to give a list of possible transformations and automatically pick the first one that fits:
-  ```py
-  attempt(
-      # Move all videos. If a video is passed in, this `re_move` will succeed
-      # and attempt short-circuits with the result.
-      re_move(r"Vorlesungsmaterial/.*/(.+?)\.mp4", "Vorlesung/Videos/{1}.mp4"),
-      # Move the whole folder to a nicer name - now without any mp4!
-      move_dir("Vorlesungsmaterial/", "Vorlesung/"),
-      # If we got another file, keep it.
-      keep,
-  )
-  ```
-
-All of these combinators are used in the provided example configs, if you want
-to see some more real-life usages.
-
-### A short, but commented example
-
-```py
-from pathlib import Path, PurePath
-from PFERD import Pferd
-from PFERD.ilias import IliasElementType
-from PFERD.transform import *
-
-# This filter will later be used by the ILIAS crawler to decide whether it
-# should crawl a directory (or directory-like structure).
-def filter_course(path: PurePath, type: IliasElementType) -> bool:
-    # Note that glob returns a Transform, which is a function from PurePath ->
-    # Optional[PurePath]. Because of this, we need to apply the result of
-    # 'glob' to our input path. The returned value will be truthy (a Path) if
-    # the transform succeeded, or `None` if it failed.
-
-    # We need to crawl the 'Tutorien' folder as it contains one that we want.
-    if glob("Tutorien/")(path):
-        return True
-    # If we found 'Tutorium 10', keep it!
-    if glob("Tutorien/Tutorium 10")(path):
-        return True
-    # Discard all other folders inside 'Tutorien'
-    if glob("Tutorien/*")(path):
-        return False
-
-    # All other dirs (including subdirs of 'Tutorium 10') should be searched :)
-    return True
-
-
-# This transform will later be used to rename a few files. It can also be used
-# to ignore some files.
-transform_course = attempt(
-    # We don't care about the other tuts and would instead prefer a cleaner
-    # directory structure.
-    move_dir("Tutorien/Tutorium 10/", "Tutorium/"),
-    # We don't want to modify any other files, so we're going to keep them
-    # exactly as they are.
-    keep
-)
-
-# Enable and configure the text output. Needs to be called before calling any
-# other PFERD methods.
-Pferd.enable_logging()
-# Create a Pferd instance rooted in the same directory as the script file. This
-# is not a test run, so files will be downloaded (default, can be omitted).
-pferd = Pferd(Path(__file__).parent, test_run=False)
-
-# Use the ilias_kit helper to synchronize an ILIAS course
-pferd.ilias_kit(
-    # The directory that all of the downloaded files should be placed in
-    "My_cool_course/",
-    # The course ID (found in the URL when on the course page in ILIAS)
-    "course id",
-    # A path to a cookie jar. If you synchronize multiple ILIAS courses,
-    # setting this to a common value requires you to only log in once.
-    cookies=Path("ilias_cookies.txt"),
-    # A transform can rename, move or filter out certain files
-    transform=transform_course,
-    # A crawl filter limits what paths the cralwer searches
-    dir_filter=filter_course,
-)
+```
+$ pferd --dump-config kit-ilias-web <url> <output_directory>
+```
+
+This will make PFERD write its current configuration to its default config file
+path. You can then run `pferd` without a command and it will execute the config
+file. Alternatively, you can use `--dump-config-to` and specify a path yourself.
+Using `--dump-config-to -` will print the configuration to stdout instead of a
+file, which is a good way to see what is actually going on when using a CLI
+command.
+
+Another good way to see what PFERD is doing is the `--explain` option. When
+enabled, PFERD explains in detail what it is doing and why. This can help with
+debugging your own config.
+
+If you don't want to run all crawlers from your config file, you can specify the
+crawlers you want to run with `--crawler` or `-C`, like this:
+
+```
+$ pferd -C crawler1 -C crawler2
+```
+
+## Advanced usage
+
+PFERD supports lots of different options. For example, you can configure PFERD
+to [use your system's keyring](CONFIG.md#the-keyring-authenticator) instead of
+prompting you for your username and password. PFERD also supports
+[transformation rules](CONFIG.md#transformation-rules) that let you rename or
+exclude certain files.
+
+For more details, see the comprehensive [config format documentation](CONFIG.md).
+
+## Example
+
+This example downloads a few courses from the KIT ILIAS with a common keyring
+authenticator. It reorganizes and ignores some files.
+
+```ini
+[DEFAULT]
+# All paths will be relative to this.
+# The crawler output directories will be <working_dir>/Foo and <working_dir>/Bar.
+working_dir = ~/stud
+# If files vanish from ILIAS the local files are not deleted, allowing us to
+# take a look at them before deleting them ourselves.
+on_conflict = no-delete
+
+[auth:ilias]
+type = keyring
+username = foo
+
+[crawl:Foo]
+type = kit-ilias-web
+auth = auth:ilias
+# Crawl a course by its ID (found as `ref_id=ID` in the URL)
+target = 1234567
+
+# Plaintext files are easier to read by other tools
+links = plaintext
+
+transform =
+  # Ignore unneeded folders
+  Online-Tests --> !
+  Vorlesungswerbung --> !
+
+  # Rename folders
+  Lehrbücher --> Vorlesung
+  # Note the ">>" arrow head which lets us apply further rules to files moved to "Übung"
+  Übungsunterlagen -->> Übung
+
+  # Move exercises to own folder. Rename them to "Blatt-XX.pdf" to make them sort properly
+  "Übung/(\d+). Übungsblatt.pdf" -re-> Blätter/Blatt-{i1:02}.pdf
+  # Move solutions to own folder. Rename them to "Blatt-XX-Lösung.pdf" to make them sort properly
+  "Übung/(\d+). Übungsblatt.*Musterlösung.pdf" -re-> Blätter/Blatt-{i1:02}-Lösung.pdf
+
+  # The course has nested folders with the same name - flatten them
+  "Übung/(.+?)/\\1" -re-> Übung/{g1}
+
+[crawl:Bar]
+type = kit-ilias-web
+auth = auth:ilias
+target = 1337420
 ```

example_config.py

@@ -1,131 +0,0 @@
-import argparse
-from pathlib import Path, PurePath
-
-from PFERD import Pferd
-from PFERD.ilias import IliasElementType
-from PFERD.transform import (attempt, do, glob, keep, move, move_dir,
-                             optionally, re_move, re_rename)
-
-tf_ss_2020_numerik = attempt(
-    re_move(r"Übungsblätter/(\d+)\. Übungsblatt/.*", "Blätter/Blatt_{1:0>2}.pdf"),
-    keep,
-)
-
-
-tf_ss_2020_db = attempt(
-    move_dir("Begrüßungsvideo/", "Vorlesung/Videos/"),
-    do(
-        move_dir("Vorlesungsmaterial/Vorlesungsvideos/", "Vorlesung/Videos/"),
-        optionally(re_rename("(.*).m4v.mp4", "{1}.mp4")),
-        optionally(re_rename("(?i)dbs-(.+)", "{1}")),
-    ),
-    move_dir("Vorlesungsmaterial/", "Vorlesung/"),
-    keep,
-)
-
-
-tf_ss_2020_rechnernetze = attempt(
-    re_move(r"Vorlesungsmaterial/.*/(.+?)\.mp4", "Vorlesung/Videos/{1}.mp4"),
-    move_dir("Vorlesungsmaterial/", "Vorlesung/"),
-    keep,
-)
-
-
-tf_ss_2020_sicherheit = attempt(
-    move_dir("Vorlesungsvideos/", "Vorlesung/Videos/"),
-    move_dir("Übungsvideos/", "Übung/Videos/"),
-    re_move(r"VL(.*)\.pdf", "Vorlesung/{1}.pdf"),
-    re_move(r"Übungsblatt (\d+)\.pdf", "Blätter/Blatt_{1:0>2}.pdf"),
-    move("Chiffrat.txt", "Blätter/Blatt_01_Chiffrat.txt"),
-    keep,
-)
-
-
-tf_ss_2020_pg = attempt(
-    move_dir("Vorlesungsaufzeichnungen/", "Vorlesung/Videos/"),
-    move_dir("Vorlesungsmaterial/", "Vorlesung/"),
-    re_move(r"Übungen/uebungsblatt(\d+).pdf", "Blätter/Blatt_{1:0>2}.pdf"),
-    keep,
-)
-
-
-def df_ss_2020_or1(path: PurePath, _type: IliasElementType) -> bool:
-    if glob("Tutorien/")(path):
-        return True
-    if glob("Tutorien/Tutorium 10, dienstags 15:45 Uhr/")(path):
-        return True
-    if glob("Tutorien/*")(path):
-        return False
-    return True
-
-
-tf_ss_2020_or1 = attempt(
-    move_dir("Vorlesung/Unbeschriebene Folien/", "Vorlesung/Folien/"),
-    move_dir("Video zur Organisation/", "Vorlesung/Videos/"),
-    keep,
-)
-
-
-def main() -> None:
-    parser = argparse.ArgumentParser()
-    parser.add_argument("--test-run", action="store_true")
-    parser.add_argument("synchronizers", nargs="*")
-    args = parser.parse_args()
-
-    pferd = Pferd(Path(__file__).parent, test_run=args.test_run)
-    pferd.enable_logging()
-
-    if not args.synchronizers or "numerik" in args.synchronizers:
-        pferd.ilias_kit(
-            target="Numerik",
-            course_id="1083036",
-            transform=tf_ss_2020_numerik,
-            cookies="ilias_cookies.txt",
-        )
-
-    if not args.synchronizers or "db" in args.synchronizers:
-        pferd.ilias_kit(
-            target="DB",
-            course_id="1101554",
-            transform=tf_ss_2020_db,
-            cookies="ilias_cookies.txt",
-        )
-
-    if not args.synchronizers or "rechnernetze" in args.synchronizers:
-        pferd.ilias_kit(
-            target="Rechnernetze",
-            course_id="1099996",
-            transform=tf_ss_2020_rechnernetze,
-            cookies="ilias_cookies.txt",
-        )
-
-    if not args.synchronizers or "sicherheit" in args.synchronizers:
-        pferd.ilias_kit(
-            target="Sicherheit",
-            course_id="1101980",
-            transform=tf_ss_2020_sicherheit,
-            cookies="ilias_cookies.txt",
-        )
-
-    if not args.synchronizers or "pg" in args.synchronizers:
-        pferd.ilias_kit(
-            target="PG",
-            course_id="1106095",
-            transform=tf_ss_2020_pg,
-            cookies="ilias_cookies.txt",
-        )
-
-    if not args.synchronizers or "or1" in args.synchronizers:
-        pferd.ilias_kit(
-            target="OR1",
-            course_id="1105941",
-            dir_filter=df_ss_2020_or1,
-            transform=tf_ss_2020_or1,
-            cookies="ilias_cookies.txt",
-        )
-
-    # Prints a summary listing all new, modified or deleted files
-    pferd.print_summary()
-
-if __name__ == "__main__":
-    main()

example_config_personal_desktop.py

@@ -1,38 +0,0 @@
-"""
-This is a small config that just crawls the ILIAS Personal Desktop.
-It does not filter or rename anything, it just gobbles up everything it can find.
-
-Note that this still includes a test-run switch, so you can see what it *would* download.
-You can enable that with the "--test-run" command line switch,
-i. e. "python3 example_config_minimal.py --test-run".
-"""
-
-import argparse
-from pathlib import Path
-
-from PFERD import Pferd
-
-
-def main() -> None:
-    # Parse command line arguments
-    parser = argparse.ArgumentParser()
-    parser.add_argument("--test-run", action="store_true")
-    args = parser.parse_args()
-
-    # Create the Pferd helper instance
-    pferd = Pferd(Path(__file__).parent, test_run=args.test_run)
-    pferd.enable_logging()
-
-    # Synchronize the personal desktop into the "ILIAS" directory.
-    # It saves the cookies, so you only need to log in again when the ILIAS cookies expire.
-    pferd.ilias_kit_personal_desktop(
-        "ILIAS",
-        cookies="ilias_cookies.txt",
-    )
-
-    # Prints a summary listing all new, modified or deleted files
-    pferd.print_summary()
-
-
-if __name__ == "__main__":
-    main()

flake.lock

@@ -0,0 +1,27 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1694499547,
+        "narHash": "sha256-R7xMz1Iia6JthWRHDn36s/E248WB1/je62ovC/dUVKI=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "e5f018cf150e29aac26c61dac0790ea023c46b24",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-23.05",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,41 @@
+{
+  description = "Tool for downloading course-related files from ILIAS";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-23.05";
+  };
+
+  outputs = { self, nixpkgs }:
+    let
+      # Helper function to generate an attrset '{ x86_64-linux = f "x86_64-linux"; ... }'.
+      forAllSystems = nixpkgs.lib.genAttrs nixpkgs.lib.systems.flakeExposed;
+    in
+    {
+      packages = forAllSystems (system:
+        let pkgs = import nixpkgs { inherit system; };
+        in
+        rec {
+          default = pkgs.python3Packages.buildPythonApplication rec {
+            pname = "pferd";
+            # Performing black magic
+            # Don't worry, I sacrificed enough goats for the next few years
+            version = (pkgs.lib.importTOML ./PFERD/version.py).VERSION;
+            format = "pyproject";
+
+            src = ./.;
+
+            nativeBuildInputs = with pkgs.python3Packages; [
+              setuptools
+            ];
+
+            propagatedBuildInputs = with pkgs.python3Packages; [
+              aiohttp
+              beautifulsoup4
+              rich
+              keyring
+              certifi
+            ];
+          };
+        });
+    };
+}

mypy.ini

@@ -1,7 +1,11 @@
 [mypy]
+disallow_any_generics = True
 disallow_untyped_defs = True
 disallow_incomplete_defs = True
 no_implicit_optional = True
+warn_unused_ignores = True
+warn_unreachable = True
+show_error_context = True
 
 [mypy-rich.*,bs4,keyring]
 ignore_missing_imports = True

pferd.py

@@ -0,0 +1,6 @@
+# File used by pyinstaller to create the executable
+
+from PFERD.__main__ import main
+
+if __name__ == "__main__":
+    main()

pyproject.toml

@@ -0,0 +1,3 @@
+[build-system]
+requires = ["setuptools", "wheel"]
+build-backend = "setuptools.build_meta"

requirements.txt

@@ -1,4 +0,0 @@
-requests>=2.21.0
-beautifulsoup4>=4.7.1
-rich>=2.1.0
-keyring>=21.5.0

scripts/build

@@ -0,0 +1,5 @@
+#!/usr/bin/env bash
+
+set -e
+
+pyinstaller --onefile pferd.py

scripts/bump-version

@@ -0,0 +1,111 @@
+#!/usr/bin/env python3
+
+import argparse
+import time
+import re
+from subprocess import run
+
+
+def load_changelog():
+    with open("CHANGELOG.md") as f:
+        return list(f)
+
+
+def extract_changes(lines):
+    lines = iter(lines)
+    changes = []
+
+    # Find "Unreleased" section
+    for line in lines:
+        if line.strip() == "## Unreleased":
+            break
+    next(lines)
+
+    # Read all lines from that section
+    for line in lines:
+        if line.startswith("## "):
+            # Found the beginning of the next section
+            break
+        elif line.startswith("### "):
+            # Found a heading in the current section
+            # Remove "#" symbols so git doesn't interpret the line as a comment later
+            changes.append(line[4:])
+        else:
+            changes.append(line)
+
+    # Remove trailing empty lines
+    while changes and not changes[-1].strip():
+        changes.pop()
+
+    return changes
+
+
+def update_version(version):
+    with open("PFERD/version.py") as f:
+        text = f.read()
+
+    text = re.sub(r'VERSION = ".*"', f'VERSION = "{version}"', text)
+
+    with open("PFERD/version.py", "w") as f:
+        f.write(text)
+
+
+def update_changelog(lines, version, date):
+    lines = iter(lines)
+    new_lines = []
+
+    # Find "Unreleased" section
+    for line in lines:
+        new_lines.append(line)
+        if line.strip() == "## Unreleased":
+            break
+
+    # Add new heading below that
+    new_lines.append("\n")
+    new_lines.append(f"## {version} - {date}\n")
+
+    # Add remaining lines
+    for line in lines:
+        new_lines.append(line)
+
+    with open("CHANGELOG.md", "w") as f:
+        f.write("".join(new_lines))
+
+
+def commit_changes(version):
+    run(["git", "add", "CHANGELOG.md", "PFERD/version.py"])
+    run(["git", "commit", "-m", f"Bump version to {version}"])
+
+
+def create_tag(version, annotation):
+    run(["git", "tag", "-am", annotation, f"v{version}"])
+
+
+def fastforward_latest():
+    run(["git", "branch", "-f", "latest", "HEAD"])
+
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument("version")
+    args = parser.parse_args()
+
+    version = args.version
+    date = time.strftime("%Y-%m-%d")
+    changelog = load_changelog()
+    changes = extract_changes(changelog)
+    annotation = f"Version {version} - {date}\n\n{''.join(changes)}"
+
+    update_version(version)
+    update_changelog(changelog, version, date)
+    commit_changes(version)
+    create_tag(version, annotation)
+    fastforward_latest()
+
+    print()
+    print("Now the only thing left is to publish the changes:")
+    print(f"  $ git push origin master latest v{version}")
+
+
+if __name__ == "__main__":
+    main()

scripts/check

@@ -0,0 +1,6 @@
+#!/usr/bin/env bash
+
+set -e
+
+mypy PFERD
+flake8 PFERD

scripts/format

@@ -0,0 +1,6 @@
+#!/usr/bin/env bash
+
+set -e
+
+autopep8 --recursive --in-place PFERD
+isort PFERD

scripts/setup

@@ -0,0 +1,17 @@
+#!/usr/bin/env bash
+
+set -e
+
+# Updating pip and setuptools because some older versions don't recognize the
+# project setup correctly
+if [[ $1 != '--no-pip' ]]; then
+    pip install --upgrade pip
+fi
+pip install --upgrade setuptools
+
+# Installing PFERD itself
+pip install --editable .
+
+# Installing tools and type hints
+pip install --upgrade mypy flake8 autopep8 isort pyinstaller
+pip install --upgrade types-chardet types-certifi

setup.cfg

@@ -0,0 +1,23 @@
+[metadata]
+name = PFERD
+version = attr: PFERD.version.VERSION
+
+[options]
+packages = find:
+python_requires = >=3.9
+install_requires =
+  aiohttp>=3.8.1
+  beautifulsoup4>=4.10.0
+  rich>=11.0.0
+  keyring>=23.5.0
+  certifi>=2021.10.8
+
+[options.entry_points]
+console_scripts =
+  pferd = PFERD.__main__:main
+
+[flake8]
+max_line_length = 110
+
+[isort]
+line_length = 110

setup.py

@@ -1,17 +0,0 @@
-from setuptools import find_packages, setup
-
-setup(
-    name="PFERD",
-    version="2.6.0",
-    packages=find_packages(),
-    install_requires=[
-        "requests>=2.21.0",
-        "beautifulsoup4>=4.7.1",
-        "rich>=2.1.0",
-        "keyring>=21.5.0"
-    ],
-)
-
-# When updating the version, also:
-# - update the README.md installation instructions
-# - set a tag on the update commit

sync_url.py

@@ -1,159 +0,0 @@
-#!/usr/bin/env python
-
-"""
-A simple script to download a course by name from ILIAS.
-"""
-
-import argparse
-import logging
-import sys
-from pathlib import Path, PurePath
-from typing import Optional
-from urllib.parse import urlparse
-
-from PFERD import Pferd
-from PFERD.authenticators import KeyringAuthenticator, UserPassAuthenticator
-from PFERD.cookie_jar import CookieJar
-from PFERD.ilias import (IliasCrawler, IliasElementType,
-                         KitShibbolethAuthenticator)
-from PFERD.logging import PrettyLogger, enable_logging
-from PFERD.organizer import (ConflictType, FileConflictResolution,
-                             FileConflictResolver, resolve_prompt_user)
-from PFERD.transform import sanitize_windows_path
-from PFERD.utils import to_path
-
-_LOGGER = logging.getLogger("sync_url")
-_PRETTY = PrettyLogger(_LOGGER)
-
-
-def _extract_credentials(file_path: Optional[str]) -> UserPassAuthenticator:
-    if not file_path:
-        return UserPassAuthenticator("KIT ILIAS Shibboleth", None, None)
-
-    if not Path(file_path).exists():
-        _PRETTY.error("Credential file does not exist")
-        sys.exit(1)
-
-    with open(file_path, "r") as file:
-        first_line = file.read().splitlines()[0]
-        read_name, *read_password = first_line.split(":", 1)
-
-        name = read_name if read_name else None
-        password = read_password[0] if read_password else None
-        return UserPassAuthenticator("KIT ILIAS Shibboleth", username=name, password=password)
-
-
-def _resolve_remote_first(_path: PurePath, _conflict: ConflictType) -> FileConflictResolution:
-    return FileConflictResolution.DESTROY_EXISTING
-
-
-def _resolve_local_first(_path: PurePath, _conflict: ConflictType) -> FileConflictResolution:
-    return FileConflictResolution.KEEP_EXISTING
-
-
-def _resolve_no_delete(_path: PurePath, conflict: ConflictType) -> FileConflictResolution:
-    # Update files
-    if conflict == ConflictType.FILE_OVERWRITTEN:
-        return FileConflictResolution.DESTROY_EXISTING
-    if conflict == ConflictType.MARKED_FILE_OVERWRITTEN:
-        return FileConflictResolution.DESTROY_EXISTING
-    # But do not delete them
-    return FileConflictResolution.KEEP_EXISTING
-
-
-def main() -> None:
-    enable_logging(name="sync_url")
-
-    parser = argparse.ArgumentParser()
-    parser.add_argument("--test-run", action="store_true")
-    parser.add_argument('-c', '--cookies', nargs='?', default=None, help="File to store cookies in")
-    parser.add_argument('-u', '--username', nargs='?', default=None, help="Username for Ilias")
-    parser.add_argument('-p', '--password', nargs='?', default=None, help="Password for Ilias")
-    parser.add_argument('--credential-file', nargs='?', default=None,
-                        help="Path to a file containing credentials for Ilias. The file must have "
-                        "one line in the following format: '<user>:<password>'")
-    parser.add_argument("-k", "--keyring", action="store_true",
-                        help="Use the system keyring service for authentication")
-    parser.add_argument('--no-videos', action="store_true", help="Don't download videos")
-    parser.add_argument('--local-first', action="store_true",
-                        help="Don't prompt for confirmation, keep existing files")
-    parser.add_argument('--remote-first', action="store_true",
-                        help="Don't prompt for confirmation, delete and overwrite local files")
-    parser.add_argument('--no-delete', action="store_true",
-                        help="Don't prompt for confirmation, overwrite local files, don't delete")
-    parser.add_argument('url', help="URL to the course page")
-    parser.add_argument('folder', nargs='?', default=None, help="Folder to put stuff into")
-    args = parser.parse_args()
-
-    cookie_jar = CookieJar(to_path(args.cookies) if args.cookies else None)
-    session = cookie_jar.create_session()
-
-    if args.keyring:
-        if not args.username:
-            _PRETTY.error("Keyring auth selected but no --username passed!")
-            return
-        inner_auth: UserPassAuthenticator = KeyringAuthenticator(
-            "KIT ILIAS Shibboleth", username=args.username, password=args.password
-        )
-    else:
-        inner_auth = _extract_credentials(args.credential_file)
-
-    username, password = inner_auth.get_credentials()
-    authenticator = KitShibbolethAuthenticator(inner_auth)
-
-    url = urlparse(args.url)
-
-    crawler = IliasCrawler(url.scheme + '://' + url.netloc, session,
-                           authenticator, lambda x, y: True)
-
-    cookie_jar.load_cookies()
-
-    if args.folder is None:
-        element_name = crawler.find_element_name(args.url)
-        if not element_name:
-            print("Error, could not get element name. Please specify a folder yourself.")
-            return
-        folder = sanitize_windows_path(Path(element_name.replace("/", "-").replace("\\", "-")))
-        cookie_jar.save_cookies()
-    else:
-        folder = Path(args.folder)
-
-    # files may not escape the pferd_root with relative paths
-    # note: Path(Path.cwd, Path(folder)) == Path(folder) if it is an absolute path
-    pferd_root = Path(Path.cwd(), Path(folder)).parent
-    target = folder.name
-    pferd = Pferd(pferd_root, test_run=args.test_run)
-
-    def dir_filter(_: Path, element: IliasElementType) -> bool:
-        if args.no_videos:
-            return element not in [IliasElementType.VIDEO_FILE, IliasElementType.VIDEO_FOLDER]
-        return True
-
-    if args.local_first:
-        file_confilict_resolver: FileConflictResolver = _resolve_local_first
-    elif args.no_delete:
-        file_confilict_resolver = _resolve_no_delete
-    elif args.remote_first:
-        file_confilict_resolver = _resolve_remote_first
-    else:
-        file_confilict_resolver = resolve_prompt_user
-
-    pferd.enable_logging()
-
-    # fetch
-    pferd.ilias_kit_folder(
-        target=target,
-        full_url=args.url,
-        cookies=args.cookies,
-        dir_filter=dir_filter,
-        username=username,
-        password=password,
-        file_conflict_resolver=file_confilict_resolver,
-        transform=sanitize_windows_path
-    )
-
-    pferd.print_summary()
-
-
-if __name__ == "__main__":
-    main()