# 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]: "Supported INI File Structure" [2]: "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`) - `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. - `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 - ``: Crawl the course with the given id - ``: 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`) - `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 `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 `bar/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][3]. The *n*-th capturing group can be referred to as `{g}` (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}` (e.g. `{i3}`). If capturing group *n*'s contents are a valid float, the float value is available as `{f}` (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` [3]: "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(' ', '_')}" ```