Merge 77c1f1516c into e41a22149e

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

.gitignore

@@ -2,6 +2,7 @@
 /.venv/
 /PFERD.egg-info/
 __pycache__/
+/.vscode/
 
 # pyinstaller
 /pferd.spec

.vscode/settings.json

@@ -1,8 +0,0 @@
-{
-    "files.insertFinalNewline": true,
-    "files.trimFinalNewlines": true,
-    "python.formatting.provider": "autopep8",
-    "python.linting.enabled": true,
-    "python.linting.flake8Enabled": true,
-    "python.linting.mypyEnabled": true,
-}

CHANGELOG.md

@@ -26,6 +26,14 @@ ambiguous situations.
 - 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
+
+### 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.
 
 ## 3.4.3 - 2022-11-29
 

CONFIG.md

@@ -26,6 +26,9 @@ default values for the other sections.
   `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`)
@@ -75,6 +78,9 @@ common to all crawlers:
       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
@@ -86,6 +92,9 @@ common to all crawlers:
   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)
+- `aliases`: List of strings that are considered as an alias when invoking with
+  the `--crawler` or `-C` flag. If there is more than one crawl section with
+  the same aliases all are selected. Thereby, you can group different crawlers.
 
 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
@@ -100,6 +109,7 @@ username = foo
 password = bar
 
 [crawl:something]
+aliases = [sth, some]
 type = some-complex-crawler
 auth = auth:example
 on_conflict = no-delete

LICENSE

@@ -1,5 +1,6 @@
 Copyright 2019-2021 Garmelon, I-Al-Istannen, danstooamerican, pavelzw,
-                    TheChristophe, Scriptim, thelukasprobst, Toorero
+                    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/__main__.py

@@ -47,6 +47,8 @@ def configure_logging_from_args(args: argparse.Namespace) -> 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
 
@@ -72,6 +74,8 @@ def configure_logging_from_config(args: argparse.Namespace, config: Config) -> N
             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)

PFERD/cli/parser.py

@@ -215,6 +215,11 @@ PARSER.add_argument(
     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(
@@ -233,6 +238,7 @@ def load_default_section(
         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

@@ -82,6 +82,9 @@ class DefaultSection(Section):
     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)
 

PFERD/crawl/crawler.py

@@ -9,6 +9,7 @@ from typing import Any, Callable, Dict, List, Optional, Sequence, Set, Tuple, Ty
 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
@@ -97,9 +98,10 @@ def anoncritical(f: AWrapped) -> AWrapped:
 
 
 class CrawlToken(ReusableAsyncContextManager[ProgressBar]):
-    def __init__(self, path: PurePath):
+    def __init__(self, limiter: Limiter, path: PurePath):
         super().__init__()
 
+        self._limiter = limiter
         self._path = path
 
     @property
@@ -108,15 +110,17 @@ class CrawlToken(ReusableAsyncContextManager[ProgressBar]):
 
     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, fs_token: FileSinkToken, path: PurePath):
+    def __init__(self, limiter: Limiter, fs_token: FileSinkToken, path: PurePath):
         super().__init__()
 
+        self._limiter = limiter
         self._fs_token = fs_token
         self._path = path
 
@@ -125,6 +129,7 @@ class DownloadToken(ReusableAsyncContextManager[Tuple[ProgressBar, FileSink]]):
         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",
@@ -230,6 +235,12 @@ class Crawler(ABC):
         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())
 
@@ -277,7 +288,7 @@ class Crawler(ABC):
             return None
 
         log.explain("Answer: Yes")
-        return CrawlToken(path)
+        return CrawlToken(self._limiter, path)
 
     async def download(
             self,
@@ -302,7 +313,7 @@ class Crawler(ABC):
             return None
 
         log.explain("Answer: Yes")
-        return DownloadToken(fs_token, path)
+        return DownloadToken(self._limiter, fs_token, path)
 
     async def _cleanup(self) -> None:
         log.explain_topic("Decision: Clean up files")

PFERD/crawl/http_crawler.py

@@ -1,9 +1,12 @@
 import asyncio
-from http.cookiejar import LWPCookieJar
+import http.cookies
+import ssl
 from pathlib import Path, PurePath
-from typing import Dict, List, Optional
+from typing import Any, Dict, List, Optional
 
-import requests
+import aiohttp
+import certifi
+from aiohttp.client import ClientTimeout
 
 from ..auth import Authenticator
 from ..config import Config
@@ -32,9 +35,9 @@ class HttpCrawler(Crawler):
 
         self._authentication_id = 0
         self._authentication_lock = asyncio.Lock()
-        self._http_timeout = section.http_timeout()  # TODO Use or remove
+        self._request_count = 0
+        self._http_timeout = section.http_timeout()
 
-        self._cookie_jar = LWPCookieJar()
         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
@@ -54,6 +57,7 @@ class HttpCrawler(Crawler):
         # 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:
@@ -102,13 +106,32 @@ class HttpCrawler(Crawler):
 
         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 cookies")
+            log.explain("Not sharing any cookies")
             cookie_jar_path = self._cookie_jar_path
         else:
             log.explain("Sharing cookies")
@@ -131,38 +154,46 @@ class HttpCrawler(Crawler):
 
         log.explain(f"Loading cookies from {fmt_real_path(cookie_jar_path)}")
         try:
-            self._cookie_jar.load(filename=str(cookie_jar_path))
+            self._load_cookies_from_file(cookie_jar_path)
         except Exception as e:
-            log.explain(f"Failed to load cookies: {e}")
+            log.explain("Failed to load cookies")
-            log.explain("Proceeding without 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._cookie_jar.save(filename=str(self._cookie_jar_path))
+            self._save_cookies_to_file(self._cookie_jar_path)
         except Exception as e:
-            log.warn(f"Failed to save cookies: {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()
 
-        self.session = requests.Session()
+        async with aiohttp.ClientSession(
-        self.session.headers["User-Agent"] = f"{NAME}/{VERSION}"
+                headers={"User-Agent": f"{NAME}/{VERSION}"},
-
+                cookie_jar=self._cookie_jar,
-        # From the request docs: "All requests code should work out of the box
+                connector=aiohttp.TCPConnector(ssl=ssl.create_default_context(cafile=certifi.where())),
-        # with externally provided instances of CookieJar, e.g. LWPCookieJar and
+                timeout=ClientTimeout(
-        # FileCookieJar."
+                    # 30 minutes. No download in the history of downloads was longer than 30 minutes.
-        # https://requests.readthedocs.io/en/latest/api/#requests.cookies.RequestsCookieJar
+                    # This is enough to transfer a 600 MB file over a 3 Mib/s connection.
-        self.session.cookies = self._cookie_jar  # type: ignore
+                    # Allowing an arbitrary value could be annoying for overnight batch jobs
-
+                    total=15 * 60,
-        with self.session:
+                    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/file_templates.py

@@ -1,6 +1,10 @@
 from enum import Enum
 from typing import Optional
 
+import bs4
+
+from PFERD.utils import soupify
+
 _link_template_plain = "{{link}}"
 _link_template_fancy = """
 <!DOCTYPE html>
@@ -94,6 +98,71 @@ _link_template_internet_shortcut = """
 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"
@@ -102,24 +171,24 @@ class Links(Enum):
     INTERNET_SHORTCUT = "internet-shortcut"
 
     def template(self) -> Optional[str]:
-        if self == self.FANCY:
+        if self == Links.FANCY:
             return _link_template_fancy
-        elif self == self.PLAINTEXT:
+        elif self == Links.PLAINTEXT:
             return _link_template_plain
-        elif self == self.INTERNET_SHORTCUT:
+        elif self == Links.INTERNET_SHORTCUT:
             return _link_template_internet_shortcut
-        elif self == self.IGNORE:
+        elif self == Links.IGNORE:
             return None
         raise ValueError("Missing switch case")
 
     def extension(self) -> Optional[str]:
-        if self == self.FANCY:
+        if self == Links.FANCY:
             return ".html"
-        elif self == self.PLAINTEXT:
+        elif self == Links.PLAINTEXT:
             return ".txt"
-        elif self == self.INTERNET_SHORTCUT:
+        elif self == Links.INTERNET_SHORTCUT:
             return ".url"
-        elif self == self.IGNORE:
+        elif self == Links.IGNORE:
             return None
         raise ValueError("Missing switch case")
 

PFERD/crawl/ilias/ilias_html_cleaner.py

@@ -82,7 +82,7 @@ def clean(soup: BeautifulSoup) -> BeautifulSoup:
             dummy.decompose()
         if len(children) > 1:
             continue
-        if type(children[0]) == Comment:
+        if isinstance(type(children[0]), Comment):
             dummy.decompose()
 
     for hrule_imposter in soup.find_all(class_="ilc_section_Separator"):

PFERD/crawl/ilias/kit_ilias_html.py

@@ -22,6 +22,7 @@ class IliasElementType(Enum):
     FOLDER = "folder"
     FORUM = "forum"
     LINK = "link"
+    LEARNING_MODULE = "learning_module"
     BOOKING = "booking"
     MEETING = "meeting"
     SURVEY = "survey"
@@ -71,6 +72,14 @@ class IliasForumThread:
     mtime: Optional[datetime]
 
 
+@dataclass
+class IliasLearningModulePage:
+    title: str
+    content: Tag
+    next_url: Optional[str]
+    previous_url: Optional[str]
+
+
 class IliasPage:
 
     def __init__(self, soup: BeautifulSoup, _page_url: str, source_element: Optional[IliasPageElement]):
@@ -79,6 +88,16 @@ class IliasPage:
         self._page_type = source_element.type if source_element else None
         self._source_name = source_element.name if source_element else ""
 
+    @staticmethod
+    def is_root_page(soup: BeautifulSoup) -> bool:
+        permalink = soup.find(id="current_perma_link")
+        if permalink is None:
+            return False
+        value = permalink.attrs.get("value")
+        if value is None:
+            return False
+        return "goto.php?target=root_" in value
+
     def get_child_elements(self) -> List[IliasPageElement]:
         """
         Return all child page elements you can find here.
@@ -126,6 +145,34 @@ class IliasPage:
 
         return BeautifulSoup(raw_html, "html.parser")
 
+    def get_learning_module_data(self) -> Optional[IliasLearningModulePage]:
+        if not self._is_learning_module_page():
+            return None
+        content = self._soup.select_one("#ilLMPageContent")
+        title = self._soup.select_one(".ilc_page_title_PageTitle").getText().strip()
+        return IliasLearningModulePage(
+            title=title,
+            content=content,
+            next_url=self._find_learning_module_next(),
+            previous_url=self._find_learning_module_prev()
+        )
+
+    def _find_learning_module_next(self) -> Optional[str]:
+        for link in self._soup.select("a.ilc_page_rnavlink_RightNavigationLink"):
+            url = self._abs_url_from_link(link)
+            if "baseClass=ilLMPresentationGUI" not in url:
+                continue
+            return url
+        return None
+
+    def _find_learning_module_prev(self) -> Optional[str]:
+        for link in self._soup.select("a.ilc_page_lnavlink_LeftNavigationLink"):
+            url = self._abs_url_from_link(link)
+            if "baseClass=ilLMPresentationGUI" not in url:
+                continue
+            return url
+        return None
+
     def get_download_forum_data(self) -> Optional[IliasDownloadForumData]:
         form = self._soup.find("form", attrs={"action": lambda x: x and "fallbackCmd=showThreads" in x})
         if not form:
@@ -212,6 +259,12 @@ class IliasPage:
             return False
         return "target=copa_" in link.get("value")
 
+    def _is_learning_module_page(self) -> bool:
+        link = self._soup.find(id="current_perma_link")
+        if not link:
+            return False
+        return "target=pg_" in link.get("value")
+
     def _contains_collapsed_future_meetings(self) -> bool:
         return self._uncollapse_future_meetings_url() is not None
 
@@ -802,6 +855,9 @@ class IliasPage:
         if "cmdClass=ilobjtestgui" in parsed_url.query:
             return IliasElementType.TEST
 
+        if "baseClass=ilLMPresentationGUI" in parsed_url.query:
+            return IliasElementType.LEARNING_MODULE
+
         # Booking and Meeting can not be detected based on the link. They do have a ref_id though, so
         # try to guess it from the image.
 

PFERD/crawl/ilias/kit_ilias_web_crawler.py

@@ -1,8 +1,11 @@
 import asyncio
+import base64
+import os
 import re
 from collections.abc import Awaitable, Coroutine
 from pathlib import PurePath
-from typing import Any, Callable, Dict, List, Optional, Set, Union, cast
+from typing import Any, Callable, Dict, List, Literal, Optional, Set, Union, cast
+from urllib.parse import urljoin
 
 import aiohttp
 import yarl
@@ -16,10 +19,10 @@ from ...output_dir import FileSink, Redownload
 from ...utils import fmt_path, soupify, url_set_query_param
 from ..crawler import AWrapped, CrawlError, CrawlToken, CrawlWarning, DownloadToken, anoncritical
 from ..http_crawler import HttpCrawler, HttpCrawlerSection
-from .file_templates import Links
+from .file_templates import Links, learning_module_template
 from .ilias_html_cleaner import clean, insert_base_markup
-from .kit_ilias_html import (IliasElementType, IliasForumThread, IliasPage, IliasPageElement,
+from .kit_ilias_html import (IliasElementType, IliasForumThread, IliasLearningModulePage, IliasPage,
-                             _sanitize_path_name, parse_ilias_forum_export)
+                             IliasPageElement, _sanitize_path_name, parse_ilias_forum_export)
 
 TargetType = Union[str, int]
 
@@ -126,6 +129,13 @@ def _iorepeat(attempts: int, name: str, failure_is_error: bool = False) -> Calla
     return decorator
 
 
+def _wrap_io_in_warning(name: str) -> Callable[[AWrapped], AWrapped]:
+    """
+    Wraps any I/O exception in a CrawlWarning.
+    """
+    return _iorepeat(1, name)
+
+
 # Crawler control flow:
 #
 #     crawl_desktop -+
@@ -219,45 +229,114 @@ instance's greatest bottleneck.
             return
         cl = maybe_cl  # Not mypy's fault, but explained here: https://github.com/python/mypy/issues/2608
 
-        def ensure_is_valid_course_id(parent: Optional[IliasPageElement], soup: BeautifulSoup) -> None:
+        elements: List[IliasPageElement] = []
-            if parent is None and expected_id is not None:
+        # A list as variable redefinitions are not propagated to outer scopes
-                perma_link_element: Tag = soup.find(id="current_perma_link")
+        description: List[BeautifulSoup] = []
-                if not perma_link_element or "crs_" not in perma_link_element.get("value"):
-                    raise CrawlError("Invalid course id? Didn't find anything looking like a course")
 
-        await self._crawl_ilias_page(url, None, cl, ensure_is_valid_course_id)
+        @_iorepeat(3, "crawling url")
+        async def gather_elements() -> None:
+            elements.clear()
+            async with cl:
+                next_stage_url: Optional[str] = url
+                current_parent = None
+
+                # Duplicated code, but the root page is special - we want to avoid fetching it twice!
+                while next_stage_url:
+                    soup = await self._get_page(next_stage_url, root_page_allowed=True)
+
+                    if current_parent is None and expected_id is not None:
+                        perma_link_element: Tag = soup.find(id="current_perma_link")
+                        if not perma_link_element or "crs_" not in perma_link_element.get("value"):
+                            raise CrawlError("Invalid course id? Didn't find anything looking like a course")
+
+                    log.explain_topic(f"Parsing HTML page for {fmt_path(cl.path)}")
+                    log.explain(f"URL: {next_stage_url}")
+                    page = IliasPage(soup, next_stage_url, current_parent)
+                    if next_element := page.get_next_stage_element():
+                        current_parent = next_element
+                        next_stage_url = next_element.url
+                    else:
+                        next_stage_url = None
+
+                elements.extend(page.get_child_elements())
+                if description_string := page.get_description():
+                    description.append(description_string)
+
+        # Fill up our task list with the found elements
+        await gather_elements()
+
+        if description:
+            await self._download_description(PurePath("."), description[0])
+
+        elements.sort(key=lambda e: e.id())
+
+        tasks: List[Awaitable[None]] = []
+        for element in elements:
+            if handle := await self._handle_ilias_element(PurePath("."), element):
+                tasks.append(asyncio.create_task(handle))
+
+        # And execute them
+        await self.gather(tasks)
+
+    async def _handle_ilias_page(
+        self,
+        url: str,
+        parent: IliasPageElement,
+        path: PurePath,
+    ) -> Optional[Coroutine[Any, Any, None]]:
+        maybe_cl = await self.crawl(path)
+        if not maybe_cl:
+            return None
+        return self._crawl_ilias_page(url, parent, maybe_cl)
 
     @anoncritical
     async def _crawl_ilias_page(
         self,
         url: str,
-        parent: Optional[IliasPageElement],
+        parent: IliasPageElement,
         cl: CrawlToken,
-        next_stage_hook: Callable[[Optional[IliasPageElement], BeautifulSoup], None] = lambda a, b: None
     ) -> None:
-        async with cl:
+        elements: List[IliasPageElement] = []
-            next_stage_url: Optional[str] = url
+        # A list as variable redefinitions are not propagated to outer scopes
-            current_parent = parent
+        description: List[BeautifulSoup] = []
 
-            while next_stage_url:
+        @_iorepeat(3, "crawling folder")
-                soup = await self._get_page(next_stage_url)
+        async def gather_elements() -> None:
-                log.explain_topic(f"Parsing HTML page for {fmt_path(cl.path)}")
+            elements.clear()
-                log.explain(f"URL: {next_stage_url}")
+            async with cl:
+                next_stage_url: Optional[str] = url
+                current_parent = parent
 
-                next_stage_hook(current_parent, soup)
+                while next_stage_url:
+                    soup = await self._get_page(next_stage_url)
+                    log.explain_topic(f"Parsing HTML page for {fmt_path(cl.path)}")
+                    log.explain(f"URL: {next_stage_url}")
+                    page = IliasPage(soup, next_stage_url, current_parent)
+                    if next_element := page.get_next_stage_element():
+                        current_parent = next_element
+                        next_stage_url = next_element.url
+                    else:
+                        next_stage_url = None
 
-                page = IliasPage(soup, next_stage_url, current_parent)
+                elements.extend(page.get_child_elements())
-                if next_element := page.get_next_stage_element():
+                if description_string := page.get_description():
-                    current_parent = next_element
+                    description.append(description_string)
-                    next_stage_url = next_element.url
-                else:
-                    next_stage_url = None
 
-        for element in sorted(page.get_child_elements(), key=lambda e: e.id()):
+        # Fill up our task list with the found elements
-            await self._handle_ilias_element(cl.path, element)
+        await gather_elements()
 
-        if description_string := page.get_description():
+        if description:
-            await self._download_description(cl.path, description_string)
+            await self._download_description(cl.path, description[0])
+
+        elements.sort(key=lambda e: e.id())
+
+        tasks: List[Awaitable[None]] = []
+        for element in elements:
+            if handle := await self._handle_ilias_element(cl.path, element):
+                tasks.append(asyncio.create_task(handle))
+
+        # And execute them
+        await self.gather(tasks)
 
     # These decorators only apply *to this method* and *NOT* to the returned
     # awaitables!
@@ -269,7 +348,7 @@ instance's greatest bottleneck.
         self,
         parent_path: PurePath,
         element: IliasPageElement,
-    ) -> None:
+    ) -> Optional[Coroutine[Any, Any, None]]:
         if element.url in self._visited_urls:
             raise CrawlWarning(
                 f"Found second path to element {element.name!r} at {element.url!r}. "
@@ -291,7 +370,7 @@ instance's greatest bottleneck.
                 return None
 
         if element.type == IliasElementType.FILE:
-            await self._handle_file(element, element_path)
+            return await self._handle_file(element, element_path)
         elif element.type == IliasElementType.FORUM:
             if not self._forums:
                 log.status(
@@ -301,7 +380,7 @@ instance's greatest bottleneck.
                     "[bright_black](enable with option 'forums')"
                 )
                 return None
-            await self._handle_forum(element, element_path)
+            return await self._handle_forum(element, element_path)
         elif element.type == IliasElementType.TEST:
             log.status(
                 "[bold bright_black]",
@@ -318,19 +397,18 @@ instance's greatest bottleneck.
                 "[bright_black](surveys contain no relevant data)"
             )
             return None
+        elif element.type == IliasElementType.LEARNING_MODULE:
+            return await self._handle_learning_module(element, element_path)
         elif element.type == IliasElementType.LINK:
-            await self._handle_link(element, element_path)
+            return await self._handle_link(element, element_path)
         elif element.type == IliasElementType.BOOKING:
-            await self._handle_booking(element, element_path)
+            return await self._handle_booking(element, element_path)
         elif element.type == IliasElementType.VIDEO:
-            await self._handle_file(element, element_path)
+            return await self._handle_file(element, element_path)
         elif element.type == IliasElementType.VIDEO_PLAYER:
-            await self._handle_video(element, element_path)
+            return await self._handle_video(element, element_path)
         elif element.type in _DIRECTORY_PAGES:
-            maybe_cl = await self.crawl(element_path)
+            return await self._handle_ilias_page(element.url, element, element_path)
-            if not maybe_cl:
-                return None
-            await self._crawl_ilias_page(element.url, element, maybe_cl)
         else:
             # This will retry it a few times, failing everytime. It doesn't make any network
             # requests, so that's fine.
@@ -340,7 +418,7 @@ instance's greatest bottleneck.
         self,
         element: IliasPageElement,
         element_path: PurePath,
-    ) -> None:
+    ) -> Optional[Coroutine[Any, Any, None]]:
         log.explain_topic(f"Decision: Crawl Link {fmt_path(element_path)}")
         log.explain(f"Links type is {self._links}")
 
@@ -357,7 +435,7 @@ instance's greatest bottleneck.
         if not maybe_dl:
             return None
 
-        await self._download_link(element, link_template_maybe, maybe_dl)
+        return self._download_link(element, link_template_maybe, maybe_dl)
 
     @anoncritical
     @_iorepeat(3, "resolving link")
@@ -449,7 +527,7 @@ instance's greatest bottleneck.
         self,
         element: IliasPageElement,
         element_path: PurePath,
-    ) -> None:
+    ) -> Optional[Coroutine[Any, Any, None]]:
         # Copy old mapping as it is likely still relevant
         if self.prev_report:
             self.report.add_custom_value(
@@ -475,7 +553,7 @@ instance's greatest bottleneck.
 
             return None
 
-        await self._download_video(element_path, element, maybe_dl)
+        return self._download_video(element_path, element, maybe_dl)
 
     def _previous_contained_videos(self, video_path: PurePath) -> List[PurePath]:
         if not self.prev_report:
@@ -557,11 +635,11 @@ instance's greatest bottleneck.
         self,
         element: IliasPageElement,
         element_path: PurePath,
-    ) -> None:
+    ) -> Optional[Coroutine[Any, Any, None]]:
         maybe_dl = await self.download(element_path, mtime=element.mtime)
         if not maybe_dl:
             return None
-        await self._download_file(element, maybe_dl)
+        return self._download_file(element, maybe_dl)
 
     @anoncritical
     @_iorepeat(3, "downloading file")
@@ -604,11 +682,11 @@ instance's greatest bottleneck.
         self,
         element: IliasPageElement,
         element_path: PurePath,
-    ) -> None:
+    ) -> Optional[Coroutine[Any, Any, None]]:
         maybe_cl = await self.crawl(element_path)
         if not maybe_cl:
             return None
-        await self._crawl_forum(element, maybe_cl)
+        return self._crawl_forum(element, maybe_cl)
 
     @_iorepeat(3, "crawling forum")
     @anoncritical
@@ -666,12 +744,141 @@ instance's greatest bottleneck.
             sink.file.write(content.encode("utf-8"))
             sink.done()
 
-    async def _get_page(self, url: str) -> BeautifulSoup:
+    async def _handle_learning_module(
+        self,
+        element: IliasPageElement,
+        element_path: PurePath,
+    ) -> Optional[Coroutine[Any, Any, None]]:
+        maybe_cl = await self.crawl(element_path)
+        if not maybe_cl:
+            return None
+        return self._crawl_learning_module(element, maybe_cl)
+
+    @_iorepeat(3, "crawling learning module")
+    @anoncritical
+    async def _crawl_learning_module(self, element: IliasPageElement, cl: CrawlToken) -> None:
+        elements: List[IliasLearningModulePage] = []
+
+        async with cl:
+            log.explain_topic(f"Parsing initial HTML page for {fmt_path(cl.path)}")
+            log.explain(f"URL: {element.url}")
+            soup = await self._get_page(element.url)
+            page = IliasPage(soup, element.url, None)
+            if next := page.get_learning_module_data():
+                elements.extend(await self._crawl_learning_module_direction(
+                    cl.path, next.previous_url, "left"
+                ))
+                elements.append(next)
+                elements.extend(await self._crawl_learning_module_direction(
+                    cl.path, next.next_url, "right"
+                ))
+
+        # Reflect their natural ordering in the file names
+        for index, lm_element in enumerate(elements):
+            lm_element.title = f"{index:02}_{lm_element.title}"
+
+        tasks: List[Awaitable[None]] = []
+        for index, elem in enumerate(elements):
+            prev_url = elements[index - 1].title if index > 0 else None
+            next_url = elements[index + 1].title if index < len(elements) - 1 else None
+            tasks.append(asyncio.create_task(
+                self._download_learning_module_page(cl.path, elem, prev_url, next_url)
+            ))
+
+        # And execute them
+        await self.gather(tasks)
+
+    async def _crawl_learning_module_direction(
+        self,
+        path: PurePath,
+        start_url: Optional[str],
+        dir: Union[Literal["left"], Literal["right"]]
+    ) -> List[IliasLearningModulePage]:
+        elements: List[IliasLearningModulePage] = []
+
+        if not start_url:
+            return elements
+
+        next_element_url: Optional[str] = start_url
+        counter = 0
+        while next_element_url:
+            log.explain_topic(f"Parsing HTML page for {fmt_path(path)} ({dir}-{counter})")
+            log.explain(f"URL: {next_element_url}")
+            soup = await self._get_page(next_element_url)
+            page = IliasPage(soup, next_element_url, None)
+            if next := page.get_learning_module_data():
+                elements.append(next)
+                if dir == "left":
+                    next_element_url = next.previous_url
+                else:
+                    next_element_url = next.next_url
+            counter += 1
+
+        return elements
+
+    @anoncritical
+    @_iorepeat(3, "saving learning module page")
+    async def _download_learning_module_page(
+        self,
+        parent_path: PurePath,
+        element: IliasLearningModulePage,
+        prev: Optional[str],
+        next: Optional[str]
+    ) -> None:
+        path = parent_path / (_sanitize_path_name(element.title) + ".html")
+        maybe_dl = await self.download(path)
+        if not maybe_dl:
+            return
+        my_path = self._transformer.transform(maybe_dl.path)
+        if not my_path:
+            return
+
+        if prev:
+            prev_p = self._transformer.transform(parent_path / (_sanitize_path_name(prev) + ".html"))
+            if prev_p:
+                prev = os.path.relpath(prev_p, my_path.parent)
+            else:
+                prev = None
+        if next:
+            next_p = self._transformer.transform(parent_path / (_sanitize_path_name(next) + ".html"))
+            if next_p:
+                next = os.path.relpath(next_p, my_path.parent)
+            else:
+                next = None
+
+        async with maybe_dl as (bar, sink):
+            content = element.content
+            content = await self.internalize_images(content)
+            sink.file.write(learning_module_template(content, maybe_dl.path.name, prev, next).encode("utf-8"))
+            sink.done()
+
+    async def internalize_images(self, tag: Tag) -> Tag:
+        """
+        Tries to fetch ILIAS images and embed them as base64 data.
+        """
+        log.explain_topic("Internalizing images")
+        for elem in tag.find_all(recursive=True):
+            if not isinstance(elem, Tag):
+                continue
+            if elem.name == "img":
+                if src := elem.attrs.get("src", None):
+                    url = urljoin(_ILIAS_URL, src)
+                    if not url.startswith(_ILIAS_URL):
+                        continue
+                    log.explain(f"Internalizing {url!r}")
+                    img = await self._get_authenticated(url)
+                    elem.attrs["src"] = "data:;base64," + base64.b64encode(img).decode()
+            if elem.name == "iframe" and elem.attrs.get("src", "").startswith("//"):
+                # For unknown reasons the protocol seems to be stripped.
+                elem.attrs["src"] = "https:" + elem.attrs["src"]
+        return tag
+
+    async def _get_page(self, url: str, root_page_allowed: bool = False) -> BeautifulSoup:
         auth_id = await self._current_auth_id()
         async with self.session.get(url) as request:
             soup = soupify(await request.read())
             if self._is_logged_in(soup):
-                return soup
+                return self._verify_page(soup, url, root_page_allowed)
 
         # We weren't authenticated, so try to do that
         await self.authenticate(auth_id)
@@ -680,14 +887,26 @@ instance's greatest bottleneck.
         async with self.session.get(url) as request:
             soup = soupify(await request.read())
             if self._is_logged_in(soup):
-                return soup
+                return self._verify_page(soup, url, root_page_allowed)
         raise CrawlError("get_page failed even after authenticating")
 
+    def _verify_page(self, soup: BeautifulSoup, url: str, root_page_allowed: bool) -> BeautifulSoup:
+        if IliasPage.is_root_page(soup) and not root_page_allowed:
+            raise CrawlError(
+                "Unexpectedly encountered ILIAS root page. "
+                "This usually happens because the ILIAS instance is broken. "
+                "If so, wait a day or two and try again. "
+                "It could also happen because a crawled element links to the ILIAS root page. "
+                "If so, use a transform with a ! as target to ignore the particular element. "
+                f"The redirect came from {url}"
+            )
+        return soup
+
     async def _post_authenticated(
         self,
         url: str,
         data: dict[str, Union[str, List[str]]]
-    ) -> BeautifulSoup:
+    ) -> bytes:
         auth_id = await self._current_auth_id()
 
         form_data = aiohttp.FormData()
@@ -707,6 +926,22 @@ instance's greatest bottleneck.
                 return await request.read()
         raise CrawlError("post_authenticated failed even after authenticating")
 
+    async def _get_authenticated(self, url: str) -> bytes:
+        auth_id = await self._current_auth_id()
+
+        async with self.session.get(url, allow_redirects=False) as request:
+            if request.status == 200:
+                return await request.read()
+
+        # We weren't authenticated, so try to do that
+        await self.authenticate(auth_id)
+
+        # Retry once after authenticating. If this fails, we will die.
+        async with self.session.get(url, allow_redirects=False) as request:
+            if request.status == 200:
+                return await request.read()
+        raise CrawlError("get_authenticated failed even after authenticating")
+
     # We repeat this as the login method in shibboleth doesn't handle I/O errors.
     # Shibboleth is quite reliable as well, the repeat is likely not critical here.
     @ _iorepeat(3, "Login", failure_is_error=True)

PFERD/crawl/kit_ipd_crawler.py

@@ -2,7 +2,7 @@ import os
 import re
 from dataclasses import dataclass
 from pathlib import PurePath
-from typing import List, Optional, Pattern, Set, Tuple, Union
+from typing import Awaitable, List, Optional, Pattern, Set, Tuple, Union
 from urllib.parse import urljoin
 
 from bs4 import BeautifulSoup, Tag
@@ -64,37 +64,42 @@ class KitIpdCrawler(HttpCrawler):
         self._file_regex = section.link_regex()
 
     async def _run(self) -> None:
-        cl = await self.crawl(PurePath("."))
+        maybe_cl = await self.crawl(PurePath("."))
-        if not cl:
+        if not maybe_cl:
             return
 
-        async with cl:
+        tasks: List[Awaitable[None]] = []
+
+        async with maybe_cl:
             for item in await self._fetch_items():
                 if isinstance(item, KitIpdFolder):
-                    await self._crawl_folder(item)
+                    tasks.append(self._crawl_folder(item))
                 else:
                     # Orphan files are placed in the root folder
-                    await self._download_file(PurePath("."), item)
+                    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
 
-        for file in folder.files:
+        tasks = [self._download_file(path, file) for file in folder.files]
-            await self._download_file(path, file)
+
+        await self.gather(tasks)
 
     async def _download_file(self, parent: PurePath, file: KitIpdFile) -> None:
         element_path = parent / file.name
-        dl = await self.download(element_path)
+        maybe_dl = await self.download(element_path)
-        if not dl:
+        if not maybe_dl:
             return
 
-        async with dl as (bar, sink):
+        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()
+        page, url = await self.get_page()
         elements: List[Tag] = self._find_file_links(page)
         items: Set[Union[KitIpdFile, KitIpdFolder]] = set()
 
@@ -154,12 +159,12 @@ class KitIpdCrawler(HttpCrawler):
 
             sink.done()
 
-    async def _get_page(self) -> Tuple[BeautifulSoup, str]:
+    async def get_page(self) -> Tuple[BeautifulSoup, str]:
-        response = self.session.get(self._url)
+        async with self.session.get(self._url) as request:
-
+            # The web page for Algorithmen für Routenplanung contains some
-        # The web page for Algorithmen für Routenplanung contains some
+            # weird comments that beautifulsoup doesn't parse correctly. This
-        # weird comments that beautifulsoup doesn't parse correctly. This
+            # hack enables those pages to be crawled, and should hopefully not
-        # hack enables those pages to be crawled, and should hopefully not
+            # cause issues on other pages.
-        # cause issues on other pages.
+            content = (await request.read()).decode("utf-8")
-        content = re.sub(r"<!--.*?-->", "", response.text)
+            content = re.sub(r"<!--.*?-->", "", content)
-        return soupify(content.encode("utf-8")), str(request.url)
+            return soupify(content.encode("utf-8")), str(request.url)

PFERD/crawl/local_crawler.py

@@ -71,6 +71,8 @@ class LocalCrawler(Crawler):
         if not cl:
             return
 
+        tasks = []
+
         async with cl:
             await asyncio.sleep(random.uniform(
                 0.5 * self._crawl_delay,
@@ -79,7 +81,9 @@ class LocalCrawler(Crawler):
 
             for child in path.iterdir():
                 pure_child = cl.path / child.name
-                await self._crawl_path(child, pure_child)
+                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()

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/logging.py

@@ -59,6 +59,7 @@ class Log:
         # 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
 
     def _update_live(self) -> None:
@@ -207,6 +208,17 @@ directly or as a GitHub issue: https://github.com/Garmelon/PFERD/issues/new
             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.
@@ -215,6 +227,14 @@ directly or as a GitHub issue: https://github.com/Garmelon/PFERD/issues/new
         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,

PFERD/output_dir.py

@@ -44,6 +44,7 @@ class OnConflict(Enum):
     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":
@@ -51,7 +52,7 @@ class OnConflict(Enum):
             return OnConflict(string)
         except ValueError:
             raise ValueError("must be one of 'prompt', 'local-first',"
-                             " 'remote-first', 'no-delete'")
+                             " 'remote-first', 'no-delete', 'no-delete-prompt-overwrite'")
 
 
 @dataclass
@@ -264,7 +265,7 @@ class OutputDirectory:
             on_conflict: OnConflict,
             path: PurePath,
     ) -> bool:
-        if on_conflict == OnConflict.PROMPT:
+        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)
@@ -283,7 +284,7 @@ class OutputDirectory:
             on_conflict: OnConflict,
             path: PurePath,
     ) -> bool:
-        if on_conflict == OnConflict.PROMPT:
+        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)
@@ -303,7 +304,7 @@ class OutputDirectory:
             path: PurePath,
             parent: PurePath,
     ) -> bool:
-        if on_conflict == OnConflict.PROMPT:
+        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)
@@ -330,7 +331,7 @@ class OutputDirectory:
             return False
         elif on_conflict == OnConflict.REMOTE_FIRST:
             return True
-        elif on_conflict == OnConflict.NO_DELETE:
+        elif on_conflict in {OnConflict.NO_DELETE, OnConflict.NO_DELETE_PROMPT_OVERWRITE}:
             return False
 
         # This should never be reached
@@ -495,7 +496,7 @@ class OutputDirectory:
             except OSError:
                 pass
         else:
-            log.status("[bold bright_magenta]", "Not deleted", fmt_path(pure))
+            log.not_deleted("[bold bright_magenta]", "Not deleted", fmt_path(pure))
             self._report.not_delete_file(pure)
 
     def load_prev_report(self) -> None:

PFERD/pferd.py

@@ -1,5 +1,5 @@
 from pathlib import Path
-from typing import Dict, List, Optional
+from typing import Dict, List, Optional, Set
 
 from rich.markup import escape
 
@@ -43,16 +43,24 @@ class Pferd:
 
         crawl_sections = [name for name, _ in config.crawl_sections()]
 
-        crawlers_to_run = []  # With crawl: prefix
+        crawlers_to_run = set()  # 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)
+                crawlers_to_run.add(section_name)
-            else:
+            # interprete name as alias of a crawler
-                log.explain(f"There's no crawler section named {section_name!r}")
+            alias_names = self._find_crawlers_by_alias(name, config)
+            if alias_names:
+                crawlers_to_run.update(alias_names)
+                log.explain_topic(f"Crawler alias {name!r} found corresponding crawler sections:")
+                for alias_name in alias_names:
+                    log.explain(f"Crawler section named {alias_name!r} with alias {name!r} exists")
+
+            if not section_name in crawl_sections and not alias_names:
+                log.explain(f"There's neither a crawler section named {section_name!r} nor does a crawler with alias {name!r} exist.")
                 unknown_names.append(name)
 
         if unknown_names:
@@ -65,6 +73,14 @@ class Pferd:
 
         return crawlers_to_run
 
+    def _find_crawlers_by_alias(self, alias: str, config: Config) -> Set[str]:
+        alias_names = set()
+        for (section_name, section) in config.crawl_sections():
+            section_aliases = section.get("aliases", [])
+            if alias in section_aliases:
+                alias_names.add(section_name)
+        return alias_names
+
     def _find_crawlers_to_run(
             self,
             config: Config,
@@ -180,7 +196,7 @@ class Pferd:
                 log.report(f"  [bold bright_magenta]Deleted[/] {fmt_path(path)}")
             for path in sorted(crawler.report.not_deleted_files):
                 something_changed = True
-                log.report(f"  [bold bright_magenta]Not deleted[/] {fmt_path(path)}")
+                log.report_not_deleted(f"  [bold bright_magenta]Not deleted[/] {fmt_path(path)}")
 
             for warning in crawler.report.encountered_warnings:
                 something_changed = True

PFERD/utils.py

@@ -92,32 +92,17 @@ def url_set_query_params(url: str, params: Dict[str, str]) -> str:
 
 
 def str_path(path: PurePath) -> str:
-    """
-    Turn a path into a string, in a platform-independent way.
-
-    This function always uses "/" as path separator, even on Windows.
-    """
     if not path.parts:
         return "."
     return "/".join(path.parts)
 
 
 def fmt_path(path: PurePath) -> str:
-    """
-    Turn a path into a delimited string.
-
-    This is useful if file or directory names contain weird characters like
-    newlines, leading/trailing whitespace or unprintable characters. This way,
-    they are escaped and visible to the user.
-    """
     return repr(str_path(path))
 
 
 def fmt_real_path(path: Path) -> str:
-    """
+    return repr(str(path.absolute()))
-    Like fmt_path, but resolves the path before converting it to a string.
-    """
-    return fmt_path(path.absolute())
 
 
 class ReusableAsyncContextManager(ABC, Generic[T]):

scripts/setup

@@ -14,4 +14,4 @@ pip install --editable .
 
 # Installing tools and type hints
 pip install --upgrade mypy flake8 autopep8 isort pyinstaller
-mypy PFERD --install-types --non-interactive
+pip install --upgrade types-chardet types-certifi

setup.cfg

@@ -11,7 +11,6 @@ install_requires =
   rich>=11.0.0
   keyring>=23.5.0
   certifi>=2021.10.8
-  requests>=2.28.1
 
 [options.entry_points]
 console_scripts =