Bump version to 3.8.0

Update minimum Python version to 3.11
Support ILIAS 9
2025-07-12 22:22:30 +02:00 · 2025-04-15 11:32:22 +02:00 · 2025-04-15 11:31:39 +02:00 · 2025-04-15 11:19:53 +02:00 · 2025-03-09 23:44:25 +01:00 · 2025-02-19 16:23:20 +01:00
24 changed files with 1566 additions and 906 deletions
--- a/.github/workflows/build-and-release.yml
+++ b/.github/workflows/build-and-release.yml
@ -14,7 +14,7 @@ jobs:
      fail-fast: false
      matrix:
        os: [ubuntu-latest, windows-latest, macos-13, macos-latest]
-        python: ["3.9"]
+        python: ["3.11"]
    steps:
      - uses: actions/checkout@v4

--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@ -22,6 +22,41 @@ ambiguous situations.

 ## Unreleased

+## 3.8.0 - 2025-04-15
+
+### Added
+- Support for ILIAS 9
+
+### Changed
+- Added prettier CSS to forum threads
+- Increase minimum supported Python version to 3.11
+
+## Fixed
+- File links in report on Windows
+- TOTP authentication in KIT Shibboleth
+- Forum crawling only considering the first 20 entries
+
+## 3.7.0 - 2024-11-13
+
+### Added
+- Support for MOB videos in page descriptions
+- Clickable links in the report to directly open new/modified/not-deleted files
+- Support for non KIT shibboleth login
+
+### Changed
+- Remove videos from description pages
+- Perform ILIAS cycle detection after processing the transform to allow
+  ignoring duplicated elements
+- Parse headings (h1-h3) as folders in kit-ipd crawler
+
+### Fixed
+- Personal desktop/dashboard/favorites crawling
+- Crawling of nested courses
+- Downloading of links with no target URL
+- Handle row flex on description pages
+- Add `<!DOCTYPE html>` heading to forum threads to fix mime type detection
+- Handle groups in cards
+
 ## 3.6.0 - 2024-10-23

 ### Added
--- a/CONFIG.md
+++ b/CONFIG.md
@ -163,12 +163,13 @@ out of the box for the corresponding universities:

 [ilias-dl]: https://github.com/V3lop5/ilias-downloader/blob/main/configs "ilias-downloader configs"

-| University    | `base_url`                           | `client_id`   |
-|---------------|--------------------------------------|---------------|
-| FH Aachen     | https://www.ili.fh-aachen.de         | elearning     |
-| Uni Köln      | https://www.ilias.uni-koeln.de/ilias | uk            |
-| Uni Konstanz  | https://ilias.uni-konstanz.de        | ILIASKONSTANZ |
-| Uni Stuttgart | https://ilias3.uni-stuttgart.de      | Uni_Stuttgart |
+| University    | `base_url`                              | `login_type` | `client_id`   |
+|---------------|-----------------------------------------|--------------|---------------|
+| FH Aachen     | https://www.ili.fh-aachen.de            | local        | elearning     |
+| Uni Köln      | https://www.ilias.uni-koeln.de/ilias    | local        | uk            |
+| Uni Konstanz  | https://ilias.uni-konstanz.de           | local        | ILIASKONSTANZ |
+| Uni Stuttgart | https://ilias3.uni-stuttgart.de         | local        | Uni_Stuttgart |
+| Uni Tübingen  | https://ovidius.uni-tuebingen.de/ilias3 | shibboleth   |               |

 If your university isn't listed, try navigating to your instance's login page.
 Assuming no custom login service is used, the URL will look something like this:
@ -180,7 +181,11 @@ Assuming no custom login service is used, the URL will look something like this:
 If the values work, feel free to submit a PR and add them to the table above.

 - `base_url`: The URL where the ILIAS instance is located. (Required)
- `client_id`: An ID used for authentication. (Required)
+- `login_type`: How you authenticate. (Required)
+    - `local`: Use `client_id` for authentication.
+    - `shibboleth`: Use shibboleth for authentication.
+- `client_id`: An ID used for authentication if `login_type` is `local`. Is
+  ignored if `login_type` is `shibboleth`.
 - `target`: The ILIAS element to crawl. (Required)
    - `desktop`: Crawl your personal desktop / dashboard
    - `<course id>`: Crawl the course with the given id
@ -191,6 +196,8 @@ If the values work, feel free to submit a PR and add them to the table above.
      and duplication warnings if you are a member of an ILIAS group. The
      `desktop` target is generally preferable.
 - `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.
--- a/2
+++ b/2
@ -1,6 +1,6 @@
 Copyright 2019-2024 Garmelon, I-Al-Istannen, danstooamerican, pavelzw,
                    TheChristophe, Scriptim, thelukasprobst, Toorero,
-                    Mr-Pine, p-fruck
+                    Mr-Pine, p-fruck, PinieP

 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
--- a/PFERD/auth/keyring.py
+++ b/PFERD/auth/keyring.py
@ -1,4 +1,4 @@
-from typing import Optional, Tuple
+from typing import Optional, Tuple, cast

 import keyring

@ -13,7 +13,7 @@ class KeyringAuthSection(AuthSection):
        return self.s.get("username")

    def keyring_name(self) -> str:
-        return self.s.get("keyring_name", fallback=NAME)
+        return cast(str, self.s.get("keyring_name", fallback=NAME))


 class KeyringAuthenticator(Authenticator):
--- a/PFERD/crawl/crawler.py
+++ b/PFERD/crawl/crawler.py
@ -149,9 +149,7 @@ class CrawlerSection(Section):
        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:"):]
+        name = name.removeprefix("crawl:")
        return Path(self.s.get("output_dir", name)).expanduser()

    def redownload(self) -> Redownload:
@ -258,6 +256,10 @@ class Crawler(ABC):
    def prev_report(self) -> Optional[Report]:
        return self._output_dir.prev_report

+    @property
+    def output_dir(self) -> OutputDirectory:
+        return self._output_dir
+
    @staticmethod
    async def gather(awaitables: Sequence[Awaitable[Any]]) -> List[Any]:
        """
@ -290,9 +292,40 @@ class Crawler(ABC):
        log.explain("Answer: Yes")
        return CrawlToken(self._limiter, path)

+    def should_try_download(
+            self,
+            path: PurePath,
+            *,
+            etag_differs: Optional[bool] = None,
+            mtime: Optional[datetime] = None,
+            redownload: Optional[Redownload] = None,
+            on_conflict: Optional[OnConflict] = None,
+    ) -> bool:
+        log.explain_topic(f"Decision: Should Download {fmt_path(path)}")
+
+        if self._transformer.transform(path) is None:
+            log.explain("Answer: No (ignored)")
+            return False
+
+        should_download = self._output_dir.should_try_download(
+            path,
+            etag_differs=etag_differs,
+            mtime=mtime,
+            redownload=redownload,
+            on_conflict=on_conflict
+        )
+        if should_download:
+            log.explain("Answer: Yes")
+            return True
+        else:
+            log.explain("Answer: No")
+            return False
+
    async def download(
            self,
            path: PurePath,
+            *,
+            etag_differs: Optional[bool] = None,
            mtime: Optional[datetime] = None,
            redownload: Optional[Redownload] = None,
            on_conflict: Optional[OnConflict] = None,
@ -307,7 +340,14 @@ class Crawler(ABC):
            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)
+        fs_token = await self._output_dir.download(
+            path,
+            transformed_path,
+            etag_differs=etag_differs,
+            mtime=mtime,
+            redownload=redownload,
+            on_conflict=on_conflict
+        )
        if fs_token is None:
            log.explain("Answer: No")
            return None
--- a/PFERD/crawl/http_crawler.py
+++ b/PFERD/crawl/http_crawler.py
@ -1,12 +1,14 @@
 import asyncio
 import http.cookies
 import ssl
+from datetime import datetime
 from pathlib import Path, PurePath
-from typing import Any, Dict, List, Optional
+from typing import Any, Dict, List, Optional, Tuple, cast

 import aiohttp
 import certifi
 from aiohttp.client import ClientTimeout
+from bs4 import Tag

 from ..auth import Authenticator
 from ..config import Config
@ -15,10 +17,12 @@ from ..utils import fmt_real_path
 from ..version import NAME, VERSION
 from .crawler import Crawler, CrawlerSection

+ETAGS_CUSTOM_REPORT_VALUE_KEY = "etags"
+

 class HttpCrawlerSection(CrawlerSection):
    def http_timeout(self) -> float:
-        return self.s.getfloat("http_timeout", fallback=20)
+        return self.s.getfloat("http_timeout", fallback=30)


 class HttpCrawler(Crawler):
@ -169,6 +173,79 @@ class HttpCrawler(Crawler):
            log.warn(f"Failed to save cookies to {fmt_real_path(self._cookie_jar_path)}")
            log.warn(str(e))

+    @staticmethod
+    def get_folder_structure_from_heading_hierarchy(file_link: Tag, drop_h1: bool = False) -> PurePath:
+        """
+        Retrieves the hierarchy of headings associated with the give file link and constructs a folder
+        structure from them.
+
+        <h1> level headings usually only appear once and serve as the page title, so they would introduce
+        redundant nesting. To avoid this, <h1> headings are ignored via the drop_h1 parameter.
+        """
+
+        def find_associated_headings(tag: Tag, level: int) -> PurePath:
+            if level == 0 or (level == 1 and drop_h1):
+                return PurePath()
+
+            level_heading = cast(Optional[Tag], tag.find_previous(name=f"h{level}"))
+
+            if level_heading is None:
+                return find_associated_headings(tag, level - 1)
+
+            folder_name = level_heading.get_text().strip()
+            return find_associated_headings(level_heading, level - 1) / folder_name
+
+        # start at level <h3> because paragraph-level headings are usually too granular for folder names
+        return find_associated_headings(file_link, 3)
+
+    def _get_previous_etag_from_report(self, path: PurePath) -> Optional[str]:
+        """
+        If available, retrieves the entity tag for a given path which was stored in the previous report.
+        """
+        if not self._output_dir.prev_report:
+            return None
+
+        etags = self._output_dir.prev_report.get_custom_value(ETAGS_CUSTOM_REPORT_VALUE_KEY) or {}
+        return etags.get(str(path))
+
+    def _add_etag_to_report(self, path: PurePath, etag: Optional[str]) -> None:
+        """
+        Adds an entity tag for a given path to the report's custom values.
+        """
+        if not etag:
+            return
+
+        etags = self._output_dir.report.get_custom_value(ETAGS_CUSTOM_REPORT_VALUE_KEY) or {}
+        etags[str(path)] = etag
+        self._output_dir.report.add_custom_value(ETAGS_CUSTOM_REPORT_VALUE_KEY, etags)
+
+    async def _request_resource_version(self, resource_url: str) -> Tuple[Optional[str], Optional[datetime]]:
+        """
+        Requests the ETag and Last-Modified headers of a resource via a HEAD request.
+        If no entity tag / modification date can be obtained, the according value will be None.
+        """
+        try:
+            async with self.session.head(resource_url) as resp:
+                if resp.status != 200:
+                    return None, None
+
+                etag_header = resp.headers.get("ETag")
+                last_modified_header = resp.headers.get("Last-Modified")
+                last_modified = None
+
+                if last_modified_header:
+                    try:
+                        # https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Last-Modified#directives
+                        datetime_format = "%a, %d %b %Y %H:%M:%S GMT"
+                        last_modified = datetime.strptime(last_modified_header, datetime_format)
+                    except ValueError:
+                        # last_modified remains None
+                        pass
+
+                return etag_header, last_modified
+        except aiohttp.ClientError:
+            return None, None
+
    async def run(self) -> None:
        self._request_count = 0
        self._cookie_jar = aiohttp.CookieJar()
@ -186,7 +263,12 @@ class HttpCrawler(Crawler):
                    connect=self._http_timeout,
                    sock_connect=self._http_timeout,
                    sock_read=self._http_timeout,
-                )
+                ),
+                # See https://github.com/aio-libs/aiohttp/issues/6626
+                # Without this aiohttp will mangle the redirect header from Shibboleth, invalidating the
+                # passed signature. Shibboleth will not accept the broken signature and authentication will
+                # fail.
+                requote_redirect_url=False
        ) as session:
            self.session = session
            try:
--- a/PFERD/crawl/ilias/async_helper.py
+++ b/PFERD/crawl/ilias/async_helper.py
@ -25,9 +25,10 @@ def _iorepeat(attempts: int, name: str, failure_is_error: bool = False) -> Calla
                except asyncio.exceptions.TimeoutError as e:  # explicit http timeouts in HttpCrawler
                    last_exception = e
                log.explain_topic(f"Retrying operation {name}. Retries left: {attempts - 1 - round}")
+                log.explain(f"Last exception: {last_exception!r}")

            if last_exception:
-                message = f"Error in I/O Operation: {last_exception}"
+                message = f"Error in I/O Operation: {last_exception!r}"
                if failure_is_error:
                    raise CrawlError(message) from last_exception
                else:
--- a/PFERD/crawl/ilias/file_templates.py
+++ b/PFERD/crawl/ilias/file_templates.py
@ -1,5 +1,5 @@
 from enum import Enum
-from typing import Optional
+from typing import Optional, cast

 import bs4

@ -126,6 +126,88 @@ _learning_module_template = """
 </html>
 """

+_forum_thread_template = """
+<!DOCTYPE html>
+<html lang="en">
+    <head>
+        <meta charset="UTF-8">
+        <title>ILIAS - Forum: {{name}}</title>
+        <style>
+            * {
+                box-sizing: border-box;
+            }
+            body {
+                font-family: 'Open Sans', Verdana, Arial, Helvetica, sans-serif;
+                padding: 8px;
+            }
+            ul, ol, p {
+                margin: 1.2em 0;
+            }
+            p {
+                margin-top: 8px;
+                margin-bottom: 8px;
+            }
+            a {
+                color: #00876c;
+                text-decoration: none;
+                cursor: pointer;
+            }
+            a:hover {
+                text-decoration: underline;
+            }
+            body > p:first-child > span:first-child {
+                font-size: 1.6em;
+            }
+            body > p:first-child > span:first-child ~ span.default {
+                display: inline-block;
+                font-size: 1.2em;
+                padding-bottom: 8px;
+            }
+            .ilFrmPostContent {
+                margin-top: 8px;
+                max-width: 64em;
+            }
+            .ilFrmPostContent > *:first-child {
+                margin-top: 0px;
+            }
+            .ilFrmPostTitle {
+                margin-top: 24px;
+                color: #00876c;
+                font-weight: bold;
+            }
+            #ilFrmPostList {
+                list-style: none;
+                padding-left: 0;
+            }
+            li.ilFrmPostRow {
+                padding: 3px 0 3px 3px;
+                margin-bottom: 24px;
+                border-left: 6px solid #dddddd;
+            }
+            .ilFrmPostRow > div {
+                display: flex;
+            }
+            .ilFrmPostImage img {
+                margin: 0 !important;
+                padding: 6px 9px 9px 6px;
+            }
+            .ilUserIcon {
+                width: 115px;
+            }
+            .small {
+                text-decoration: none;
+                font-size: 0.75rem;
+                color: #6f6f6f;
+            }
+        </style>
+    </head>
+    <body>
+    {{heading}}
+    {{content}}
+    </body>
+</html>
+""".strip()  # noqa: E501 line too long
+

 def learning_module_template(body: bs4.Tag, name: str, prev: Optional[str], next: Optional[str]) -> str:
    # Seems to be comments, ignore those.
@ -139,13 +221,13 @@ def learning_module_template(body: bs4.Tag, name: str, prev: Optional[str], next
        </div>
    """
    if prev and body.select_one(".ilc_page_lnav_LeftNavigation"):
-        text = body.select_one(".ilc_page_lnav_LeftNavigation").getText().strip()
+        text = cast(bs4.Tag, body.select_one(".ilc_page_lnav_LeftNavigation")).get_text().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()
+        text = cast(bs4.Tag, body.select_one(".ilc_page_rnav_RightNavigation")).get_text().strip()
        right = f'<a href="{next}">{text}</a>'
    else:
        right = "<span></span>"
@ -160,8 +242,17 @@ def learning_module_template(body: bs4.Tag, name: str, prev: Optional[str], next
            "{{left}}", left).replace("{{right}}", right).encode())
        )

-    body = body.prettify()
-    return _learning_module_template.replace("{{body}}", body).replace("{{name}}", name)
+    body_str = cast(str, body.prettify())
+    return _learning_module_template.replace("{{body}}", body_str).replace("{{name}}", name)
+
+
+def forum_thread_template(name: str, url: str, heading: bs4.Tag, content: bs4.Tag) -> str:
+    if title := cast(Optional[bs4.Tag], heading.find(name="b")):
+        title.wrap(bs4.Tag(name="a", attrs={"href": url}))
+    return _forum_thread_template \
+        .replace("{{name}}", name) \
+        .replace("{{heading}}", cast(str, heading.prettify())) \
+        .replace("{{content}}", cast(str, content.prettify()))


 class Links(Enum):
--- a/PFERD/crawl/ilias/ilias_html_cleaner.py
+++ b/PFERD/crawl/ilias/ilias_html_cleaner.py
@ -1,3 +1,5 @@
+from typing import cast
+
 from bs4 import BeautifulSoup, Comment, Tag

 _STYLE_TAG_CONTENT = """
@ -12,6 +14,13 @@ _STYLE_TAG_CONTENT = """
      font-weight: bold;
    }

+    .row-flex {
+      display: flex;
+    }
+    .row-flex-wrap {
+      flex-wrap: wrap;
+    }
+
    .accordion-head {
      background-color: #f5f7fa;
      padding: 0.5rem 0;
@ -63,18 +72,18 @@ def insert_base_markup(soup: BeautifulSoup) -> BeautifulSoup:


 def clean(soup: BeautifulSoup) -> BeautifulSoup:
-    for block in soup.find_all(class_=lambda x: x in _ARTICLE_WORTHY_CLASSES):
+    for block in cast(list[Tag], soup.find_all(class_=lambda x: x in _ARTICLE_WORTHY_CLASSES)):
        block.name = "article"

-    for block in soup.find_all("h3"):
+    for block in cast(list[Tag], soup.find_all("h3")):
        block.name = "div"

-    for block in soup.find_all("h1"):
+    for block in cast(list[Tag], soup.find_all("h1")):
        block.name = "h3"

-    for block in soup.find_all(class_="ilc_va_ihcap_VAccordIHeadCap"):
+    for block in cast(list[Tag], soup.find_all(class_="ilc_va_ihcap_VAccordIHeadCap")):
        block.name = "h3"
-        block["class"] += ["accordion-head"]
+        block["class"] += ["accordion-head"]  # type: ignore

    for dummy in soup.select(".ilc_text_block_Standard.ilc_Paragraph"):
        children = list(dummy.children)
@ -85,7 +94,12 @@ def clean(soup: BeautifulSoup) -> BeautifulSoup:
        if isinstance(type(children[0]), Comment):
            dummy.decompose()

-    for hrule_imposter in soup.find_all(class_="ilc_section_Separator"):
+    # Delete video figures, as they can not be internalized anyway
+    for video in soup.select(".ilc_media_cont_MediaContainerHighlighted .ilPageVideo"):
+        if figure := video.find_parent("figure"):
+            figure.decompose()
+
+    for hrule_imposter in cast(list[Tag], soup.find_all(class_="ilc_section_Separator")):
        hrule_imposter.insert(0, soup.new_tag("hr"))

    return soup
--- a/PFERD/crawl/ilias/ilias_web_crawler.py
+++ b/PFERD/crawl/ilias/ilias_web_crawler.py
@ -19,14 +19,20 @@ from ...utils import fmt_path, soupify, url_set_query_param
 from ..crawler import CrawlError, CrawlToken, CrawlWarning, DownloadToken, anoncritical
 from ..http_crawler import HttpCrawler, HttpCrawlerSection
 from .async_helper import _iorepeat
-from .file_templates import Links, learning_module_template
+from .file_templates import Links, forum_thread_template, learning_module_template
 from .ilias_html_cleaner import clean, insert_base_markup
 from .kit_ilias_html import (IliasElementType, IliasForumThread, IliasLearningModulePage, IliasPage,
-                             IliasPageElement, _sanitize_path_name, parse_ilias_forum_export)
+                             IliasPageElement, IliasSoup, _sanitize_path_name, parse_ilias_forum_export)
+from .shibboleth_login import ShibbolethLogin

 TargetType = Union[str, int]


+class LoginTypeLocal:
+    def __init__(self, client_id: str):
+        self.client_id = client_id
+
+
 class IliasWebCrawlerSection(HttpCrawlerSection):
    def base_url(self) -> str:
        base_url = self.s.get("base_url")
@ -35,12 +41,30 @@ class IliasWebCrawlerSection(HttpCrawlerSection):

        return base_url

-    def client_id(self) -> str:
+    def login(self) -> Union[Literal["shibboleth"], LoginTypeLocal]:
+        login_type = self.s.get("login_type")
+        if not login_type:
+            self.missing_value("login_type")
+        if login_type == "shibboleth":
+            return "shibboleth"
+        if login_type == "local":
            client_id = self.s.get("client_id")
            if not client_id:
                self.missing_value("client_id")
+            return LoginTypeLocal(client_id)

-        return client_id
+        self.invalid_value("login_type", login_type, "Should be <shibboleth | local>")
+
+    def tfa_auth(
+        self, authenticators: Dict[str, Authenticator]
+    ) -> Optional[Authenticator]:
+        value: Optional[str] = self.s.get("tfa_auth")
+        if value is None:
+            return None
+        auth = authenticators.get(value)
+        if auth is None:
+            self.invalid_value("tfa_auth", value, "No such auth section exists")
+        return auth

    def target(self) -> TargetType:
        target = self.s.get("target")
@ -85,19 +109,19 @@ _DIRECTORY_PAGES: Set[IliasElementType] = {
    IliasElementType.EXERCISE_FILES,
    IliasElementType.FOLDER,
    IliasElementType.INFO_TAB,
-    IliasElementType.MEETING,
    IliasElementType.MEDIACAST_VIDEO_FOLDER,
+    IliasElementType.MEETING,
    IliasElementType.OPENCAST_VIDEO_FOLDER,
    IliasElementType.OPENCAST_VIDEO_FOLDER_MAYBE_PAGINATED,
 }

 _VIDEO_ELEMENTS: Set[IliasElementType] = {
-    IliasElementType.MEDIACAST_VIDEO_FOLDER,
    IliasElementType.MEDIACAST_VIDEO,
+    IliasElementType.MEDIACAST_VIDEO_FOLDER,
    IliasElementType.OPENCAST_VIDEO,
-    IliasElementType.OPENCAST_VIDEO_PLAYER,
    IliasElementType.OPENCAST_VIDEO_FOLDER,
    IliasElementType.OPENCAST_VIDEO_FOLDER_MAYBE_PAGINATED,
+    IliasElementType.OPENCAST_VIDEO_PLAYER,
 }


@ -155,7 +179,13 @@ instance's greatest bottleneck.

        self._auth = auth
        self._base_url = section.base_url()
-        self._client_id = section.client_id()
+        self._tfa_auth = section.tfa_auth(authenticators)
+
+        self._login_type = section.login()
+        if isinstance(self._login_type, LoginTypeLocal):
+            self._client_id = self._login_type.client_id
+        else:
+            self._shibboleth_login = ShibbolethLogin(self._base_url, self._auth, self._tfa_auth)

        self._target = section.target()
        self._link_file_redirect_delay = section.link_redirect_delay()
@ -178,94 +208,43 @@ instance's greatest bottleneck.
    async def _crawl_course(self, course_id: int) -> None:
        # Start crawling at the given course
        root_url = url_set_query_param(
-            urljoin(self._base_url, "/goto.php"),
+            urljoin(self._base_url + "/", "goto.php"),
            "target", f"crs_{course_id}",
        )

        await self._crawl_url(root_url, expected_id=course_id)

    async def _crawl_desktop(self) -> None:
-        appendix = r"ILIAS\Repository\Provider\RepositoryMainBarProvider|mm_pd_sel_items"
-        appendix = appendix.encode("ASCII").hex()
-        await self._crawl_url(url_set_query_param(
-            urljoin(self._base_url, "/gs_content.php"),
-            "item=", appendix,
-        ))
+        await self._crawl_url(
+            urljoin(self._base_url, "/ilias.php?baseClass=ilDashboardGUI&cmd=show")
+        )

    async def _crawl_url(self, url: str, expected_id: Optional[int] = None) -> None:
-        maybe_cl = await self.crawl(PurePath("."))
-        if not maybe_cl:
-            return
-        cl = maybe_cl  # Not mypy's fault, but explained here: https://github.com/python/mypy/issues/2608
-
-        elements: List[IliasPageElement] = []
-        # A list as variable redefinitions are not propagated to outer scopes
-        description: List[BeautifulSoup] = []
-
-        @_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 = IliasPage.get_soup_permalink(soup)
-                        if not perma_link or "crs_" not in perma_link:
-                            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 info_tab := page.get_info_tab():
-                    elements.append(info_tab)
-                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)
+        if awaitable := await self._handle_ilias_page(url, None, PurePath("."), expected_id):
+            await awaitable

    async def _handle_ilias_page(
        self,
        url: str,
-        parent: IliasPageElement,
+        current_element: Optional[IliasPageElement],
        path: PurePath,
+        expected_course_id: Optional[int] = None,
    ) -> 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)
+        if current_element:
+            self._ensure_not_seen(current_element, path)
+
+        return self._crawl_ilias_page(url, current_element, maybe_cl, expected_course_id)

    @anoncritical
    async def _crawl_ilias_page(
        self,
        url: str,
-        parent: IliasPageElement,
+        current_element: Optional[IliasPageElement],
        cl: CrawlToken,
+        expected_course_id: Optional[int] = None,
    ) -> None:
        elements: List[IliasPageElement] = []
        # A list as variable redefinitions are not propagated to outer scopes
@ -276,19 +255,30 @@ instance's greatest bottleneck.
            elements.clear()
            async with cl:
                next_stage_url: Optional[str] = url
-                current_parent = parent
+                current_parent = current_element
+                page = None

                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 we expect to find a root course, enforce it
+                    if current_parent is None and expected_course_id is not None:
+                        perma_link = IliasPage.get_soup_permalink(soup)
+                        if not perma_link or "crs/" not in perma_link:
+                            raise CrawlError("Invalid course id? Didn't find anything looking like a course")
+                        if str(expected_course_id) not in perma_link:
+                            raise CrawlError(f"Expected course id {expected_course_id} but got {perma_link}")
+
+                    page = IliasPage(soup, 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 = cast(IliasPage, page)
                elements.extend(page.get_child_elements())
                if description_string := page.get_description():
                    description.append(description_string)
@ -320,14 +310,6 @@ instance's greatest bottleneck.
        parent_path: PurePath,
        element: IliasPageElement,
    ) -> 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}. "
-                + f"First path: {fmt_path(self._visited_urls[element.url])}. "
-                + f"Second path: {fmt_path(parent_path)}."
-            )
-        self._visited_urls[element.url] = parent_path
-
        # element.name might contain `/` if the crawler created nested elements,
        # so we can not sanitize it here. We trust in the output dir to thwart worst-case
        # directory escape attacks.
@ -379,6 +361,54 @@ instance's greatest bottleneck.
                "[bright_black](scorm learning modules are not supported)"
            )
            return None
+        elif element.type == IliasElementType.LITERATURE_LIST:
+            log.status(
+                "[bold bright_black]",
+                "Ignored",
+                fmt_path(element_path),
+                "[bright_black](literature lists are not currently supported)"
+            )
+            return None
+        elif element.type == IliasElementType.LEARNING_MODULE_HTML:
+            log.status(
+                "[bold bright_black]",
+                "Ignored",
+                fmt_path(element_path),
+                "[bright_black](HTML learning modules are not supported)"
+            )
+            return None
+        elif element.type == IliasElementType.BLOG:
+            log.status(
+                "[bold bright_black]",
+                "Ignored",
+                fmt_path(element_path),
+                "[bright_black](blogs are not currently supported)"
+            )
+            return None
+        elif element.type == IliasElementType.DCL_RECORD_LIST:
+            log.status(
+                "[bold bright_black]",
+                "Ignored",
+                fmt_path(element_path),
+                "[bright_black](dcl record lists are not currently supported)"
+            )
+            return None
+        elif element.type == IliasElementType.MEDIA_POOL:
+            log.status(
+                "[bold bright_black]",
+                "Ignored",
+                fmt_path(element_path),
+                "[bright_black](media pools are not currently supported)"
+            )
+            return None
+        elif element.type == IliasElementType.COURSE:
+            log.status(
+                "[bold bright_black]",
+                "Ignored",
+                fmt_path(element_path),
+                "[bright_black](not descending into linked course, download it separately)"
+            )
+            return None
        elif element.type == IliasElementType.LEARNING_MODULE:
            return await self._handle_learning_module(element, element_path)
        elif element.type == IliasElementType.LINK:
@ -391,6 +421,8 @@ instance's greatest bottleneck.
            return await self._handle_opencast_video(element, element_path)
        elif element.type == IliasElementType.MEDIACAST_VIDEO:
            return await self._handle_file(element, element_path)
+        elif element.type == IliasElementType.MOB_VIDEO:
+            return await self._handle_file(element, element_path, is_video=True)
        elif element.type in _DIRECTORY_PAGES:
            return await self._handle_ilias_page(element.url, element, element_path)
        else:
@ -466,6 +498,8 @@ instance's greatest bottleneck.
        if not maybe_dl:
            return None

+        self._ensure_not_seen(element, element_path)
+
        return self._download_booking(element, link_template_maybe, maybe_dl)

    @anoncritical
@ -476,9 +510,10 @@ instance's greatest bottleneck.
        if not dl:
            return

-        async with dl as (bar, sink):
+        async with dl as (_bar, sink):
            description = clean(insert_base_markup(description))
-            sink.file.write(description.prettify().encode("utf-8"))
+            description_tag = await self.internalize_images(description)
+            sink.file.write(cast(str, description_tag.prettify()).encode("utf-8"))
            sink.done()

    @anoncritical
@ -493,17 +528,27 @@ instance's greatest bottleneck.
            self._write_link_content(link_template, element.url, element.name, element.description, sink)

    async def _resolve_link_target(self, export_url: str) -> str:
+        async def impl() -> Optional[str]:
            async with self.session.get(export_url, allow_redirects=False) as resp:
                # No redirect means we were authenticated
                if hdrs.LOCATION not in resp.headers:
-                return soupify(await resp.read()).select_one("a").get("href").strip()
+                    return soupify(await resp.read()).select_one("a").get("href").strip()  # type: ignore
+                # We are either unauthenticated or the link is not active
+                new_url = resp.headers[hdrs.LOCATION].lower()
+                if "baseclass=illinkresourcehandlergui" in new_url and "cmd=infoscreen" in new_url:
+                    return ""
+                return None

-        await self._authenticate()
+        auth_id = await self._current_auth_id()
+        target = await impl()
+        if target is not None:
+            return target

-        async with self.session.get(export_url, allow_redirects=False) as resp:
-            # No redirect means we were authenticated
-            if hdrs.LOCATION not in resp.headers:
-                return soupify(await resp.read()).select_one("a").get("href").strip()
+        await self.authenticate(auth_id)
+
+        target = await impl()
+        if target is not None:
+            return target

        raise CrawlError("resolve_link_target failed even after authenticating")

@ -530,6 +575,8 @@ instance's greatest bottleneck.
        if not maybe_dl:
            return None

+        self._ensure_not_seen(element, element_path)
+
        # If we have every file from the cached mapping already, we can ignore this and bail
        if self._all_opencast_videos_locally_present(element, maybe_dl.path):
            # Mark all existing videos as known to ensure they do not get deleted during cleanup.
@ -590,7 +637,7 @@ instance's greatest bottleneck.
            )

        async with dl as (bar, sink):
-            page = IliasPage(await self._get_page(element.url), element.url, element)
+            page = IliasPage(await self._get_page(element.url), element)
            stream_elements = page.get_child_elements()

            if len(stream_elements) > 1:
@ -600,7 +647,7 @@ instance's greatest bottleneck.
                stream_element = stream_elements[0]

                # We do not have a local cache yet
-                await self._stream_from_url(stream_element.url, sink, bar, is_video=True)
+                await self._stream_from_url(stream_element, sink, bar, is_video=True)
                add_to_report([str(self._transformer.transform(dl.path))])
                return

@ -615,7 +662,7 @@ instance's greatest bottleneck.
            async with maybe_dl as (bar, sink):
                log.explain(f"Streaming video from real url {stream_element.url}")
                contained_video_paths.append(str(self._transformer.transform(maybe_dl.path)))
-                await self._stream_from_url(stream_element.url, sink, bar, is_video=True)
+                await self._stream_from_url(stream_element, sink, bar, is_video=True)

        add_to_report(contained_video_paths)

@ -623,23 +670,33 @@ instance's greatest bottleneck.
        self,
        element: IliasPageElement,
        element_path: PurePath,
+        is_video: bool = False,
    ) -> Optional[Coroutine[Any, Any, None]]:
        maybe_dl = await self.download(element_path, mtime=element.mtime)
        if not maybe_dl:
            return None
-        return self._download_file(element, maybe_dl)
+        self._ensure_not_seen(element, element_path)
+
+        return self._download_file(element, maybe_dl, is_video)

    @_iorepeat(3, "downloading file")
    @anoncritical
-    async def _download_file(self, element: IliasPageElement, dl: DownloadToken) -> None:
+    async def _download_file(self, element: IliasPageElement, dl: DownloadToken, is_video: bool) -> None:
        assert dl  # The function is only reached when dl is not None
        async with dl as (bar, sink):
-            await self._stream_from_url(element.url, sink, bar, is_video=False)
+            await self._stream_from_url(element, sink, bar, is_video)
+
+    async def _stream_from_url(
+        self,
+        element: IliasPageElement,
+        sink: FileSink,
+        bar: ProgressBar,
+        is_video: bool
+    ) -> None:
+        url = element.url

-    async def _stream_from_url(self, url: str, sink: FileSink, bar: ProgressBar, is_video: bool) -> None:
        async def try_stream() -> bool:
            next_url = url
-
            # Normal files redirect to the magazine if we are not authenticated. As files could be HTML,
            # we can not match on the content type here. Instead, we disallow redirects and inspect the
            # new location. If we are redirected anywhere but the ILIAS 8 "sendfile" command, we assume
@ -663,6 +720,13 @@ instance's greatest bottleneck.
                if is_video and "html" in resp.content_type:
                    return False

+                # https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Range
+                if content_range := resp.headers.get(hdrs.CONTENT_RANGE, default=None):
+                    parts = content_range.split("/")
+                    if len(parts) == 2 and parts[1].isdigit():
+                        bar.set_total(int(parts[1]))
+
+                # Prefer the content length header
                if resp.content_length:
                    bar.set_total(resp.content_length)

@ -680,7 +744,7 @@ instance's greatest bottleneck.
        await self.authenticate(auth_id)

        if not await try_stream():
-            raise CrawlError("File streaming failed after authenticate()")
+            raise CrawlError(f"File streaming failed after authenticate() {element!r}")

    async def _handle_forum(
        self,
@ -699,32 +763,66 @@ instance's greatest bottleneck.

        async with cl:
            next_stage_url = element.url
+            page = None
+
            while next_stage_url:
                log.explain_topic(f"Parsing HTML page for {fmt_path(cl.path)}")
                log.explain(f"URL: {next_stage_url}")

                soup = await self._get_page(next_stage_url)
-                page = IliasPage(soup, next_stage_url, element)
+                page = IliasPage(soup, element)

                if next := page.get_next_stage_element():
                    next_stage_url = next.url
                else:
                    break

-            download_data = page.get_download_forum_data()
-            if not download_data:
-                raise CrawlWarning("Failed to extract forum data")
-            if download_data.empty:
+            forum_threads: list[tuple[IliasPageElement, bool]] = []
+            for entry in cast(IliasPage, page).get_forum_entries():
+                path = cl.path / (_sanitize_path_name(entry.name) + ".html")
+                forum_threads.append((entry, self.should_try_download(path, mtime=entry.mtime)))
+
+            # Sort the ids. The forum download will *preserve* this ordering
+            forum_threads.sort(key=lambda elem: elem[0].id())
+
+            if not forum_threads:
                log.explain("Forum had no threads")
                return
+
+            download_data = cast(IliasPage, page).get_download_forum_data(
+                [thread.id() for thread, download in forum_threads if download]
+            )
+            if not download_data:
+                raise CrawlWarning("Failed to extract forum data")
+
+            if not download_data.empty:
                html = await self._post_authenticated(download_data.url, download_data.form_data)
                elements = parse_ilias_forum_export(soupify(html))
+            else:
+                elements = []

-        elements.sort(key=lambda elem: elem.title)
+        # Verify that ILIAS does not change the order, as we depend on it later. Otherwise, we could not call
+        # download in the correct order, potentially messing up duplication handling.
+        expected_element_titles = [thread.name for thread, download in forum_threads if download]
+        actual_element_titles = [_sanitize_path_name(thread.name) for thread in elements]
+        if expected_element_titles != actual_element_titles:
+            raise CrawlWarning(
+                f"Forum thread order mismatch: {expected_element_titles} != {actual_element_titles}"
+            )

        tasks: List[Awaitable[None]] = []
-        for elem in elements:
-            tasks.append(asyncio.create_task(self._download_forum_thread(cl.path, elem)))
+        for thread, download in forum_threads:
+            if download:
+                # This only works because ILIAS keeps the order in the export
+                elem = elements.pop(0)
+                tasks.append(asyncio.create_task(self._download_forum_thread(cl.path, elem, thread)))
+            else:
+                # We only downloaded the threads we "should_try_download"ed. This can be an
+                # over-approximation and all will be fine.
+                # If we selected too few, e.g. because there was a duplicate title and the mtime of the
+                # original is newer than the update of the duplicate.
+                # This causes stale data locally, but I consider this problem acceptable right now.
+                tasks.append(asyncio.create_task(self._download_forum_thread(cl.path, thread, thread)))

        # And execute them
        await self.gather(tasks)
@ -734,17 +832,22 @@ instance's greatest bottleneck.
    async def _download_forum_thread(
        self,
        parent_path: PurePath,
-        element: IliasForumThread,
+        thread: Union[IliasForumThread, IliasPageElement],
+        element: IliasPageElement
    ) -> None:
-        path = parent_path / (_sanitize_path_name(element.title) + ".html")
-        maybe_dl = await self.download(path, mtime=element.mtime)
-        if not maybe_dl:
+        path = parent_path / (_sanitize_path_name(thread.name) + ".html")
+        maybe_dl = await self.download(path, mtime=thread.mtime)
+        if not maybe_dl or not isinstance(thread, IliasForumThread):
            return

        async with maybe_dl as (bar, sink):
-            content = element.title_tag.prettify()
-            content += element.content_tag.prettify()
-            sink.file.write(content.encode("utf-8"))
+            rendered = forum_thread_template(
+                thread.name,
+                element.url,
+                thread.name_tag,
+                await self.internalize_images(thread.content_tag)
+            )
+            sink.file.write(rendered.encode("utf-8"))
            sink.done()

    async def _handle_learning_module(
@ -755,6 +858,8 @@ instance's greatest bottleneck.
        maybe_cl = await self.crawl(element_path)
        if not maybe_cl:
            return None
+        self._ensure_not_seen(element, element_path)
+
        return self._crawl_learning_module(element, maybe_cl)

    @_iorepeat(3, "crawling learning module")
@ -766,7 +871,7 @@ instance's greatest bottleneck.
            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, element)
+            page = IliasPage(soup, element)
            if next := page.get_learning_module_data():
                elements.extend(await self._crawl_learning_module_direction(
                    cl.path, next.previous_url, "left", element
@ -809,7 +914,7 @@ instance's greatest bottleneck.
            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, parent_element)
+            page = IliasPage(soup, parent_element)
            if next := page.get_learning_module_data():
                elements.append(next)
                if dir == "left":
@ -840,13 +945,13 @@ instance's greatest bottleneck.
        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)
+                prev = cast(str, 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)
+                next = cast(str, os.path.relpath(next_p, my_path.parent))
            else:
                next = None

@ -866,21 +971,30 @@ instance's greatest bottleneck.
                continue
            if elem.name == "img":
                if src := elem.attrs.get("src", None):
-                    url = urljoin(self._base_url, src)
+                    url = urljoin(self._base_url, cast(str, src))
                    if not url.startswith(self._base_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("//"):
+            if elem.name == "iframe" and cast(str, elem.attrs.get("src", "")).startswith("//"):
                # For unknown reasons the protocol seems to be stripped.
-                elem.attrs["src"] = "https:" + elem.attrs["src"]
+                elem.attrs["src"] = "https:" + cast(str, elem.attrs["src"])
        return tag

-    async def _get_page(self, url: str, root_page_allowed: bool = False) -> BeautifulSoup:
+    def _ensure_not_seen(self, element: IliasPageElement, parent_path: PurePath) -> None:
+        if element.url in self._visited_urls:
+            raise CrawlWarning(
+                f"Found second path to element {element.name!r} at {element.url!r}. "
+                + f"First path: {fmt_path(self._visited_urls[element.url])}. "
+                + f"Second path: {fmt_path(parent_path)}."
+            )
+        self._visited_urls[element.url] = parent_path
+
+    async def _get_page(self, url: str, root_page_allowed: bool = False) -> IliasSoup:
        auth_id = await self._current_auth_id()
        async with self.session.get(url) as request:
-            soup = soupify(await request.read())
+            soup = IliasSoup(soupify(await request.read()), str(request.url))
            if IliasPage.is_logged_in(soup):
                return self._verify_page(soup, url, root_page_allowed)

@ -889,13 +1003,13 @@ instance's greatest bottleneck.

        # Retry once after authenticating. If this fails, we will die.
        async with self.session.get(url) as request:
-            soup = soupify(await request.read())
+            soup = IliasSoup(soupify(await request.read()), str(request.url))
            if IliasPage.is_logged_in(soup):
                return self._verify_page(soup, url, root_page_allowed)
        raise CrawlError(f"get_page failed even after authenticating on {url!r}")

    @staticmethod
-    def _verify_page(soup: BeautifulSoup, url: str, root_page_allowed: bool) -> BeautifulSoup:
+    def _verify_page(soup: IliasSoup, url: str, root_page_allowed: bool) -> IliasSoup:
        if IliasPage.is_root_page(soup) and not root_page_allowed:
            raise CrawlError(
                "Unexpectedly encountered ILIAS root page. "
@ -947,10 +1061,11 @@ instance's greatest bottleneck.
                return await request.read()
        raise CrawlError("get_authenticated failed even after authenticating")

-    # ToDo: Is iorepeat still required?
-    @_iorepeat(3, "Login", failure_is_error=True)
    async def _authenticate(self) -> None:
        # fill the session with the correct cookies
+        if self._login_type == "shibboleth":
+            await self._shibboleth_login.login(self.session)
+        else:
            params = {
                "client_id": self._client_id,
                "cmd": "force_login",
@ -958,11 +1073,11 @@ instance's greatest bottleneck.
            async with self.session.get(urljoin(self._base_url, "/login.php"), params=params) as request:
                login_page = soupify(await request.read())

-        login_form = login_page.find("form", attrs={"name": "formlogin"})
+            login_form = cast(Optional[Tag], login_page.find("form", attrs={"name": "formlogin"}))
            if login_form is None:
                raise CrawlError("Could not find the login form! Specified client id might be invalid.")

-        login_url = login_form.attrs.get("action")
+            login_url = cast(Optional[str], login_form.attrs.get("action"))
            if login_url is None:
                raise CrawlError("Could not find the action URL in the login form!")

@ -976,34 +1091,6 @@ instance's greatest bottleneck.

            # do the actual login
            async with self.session.post(urljoin(self._base_url, login_url), data=login_data) as request:
-            soup = soupify(await request.read())
-            if not self._is_logged_in(soup):
+                soup = IliasSoup(soupify(await request.read()), str(request.url))
+                if not IliasPage.is_logged_in(soup):
                    self._auth.invalidate_credentials()
-
-    @staticmethod
-    def _is_logged_in(soup: BeautifulSoup) -> bool:
-        # Normal ILIAS pages
-        mainbar: Optional[Tag] = soup.find(class_="il-maincontrols-metabar")
-        if mainbar is not None:
-            login_button = mainbar.find(attrs={"href": lambda x: x and "login.php" in x})
-            shib_login = soup.find(id="button_shib_login")
-            return not login_button and not shib_login
-
-        # Personal Desktop
-        if soup.find("a", attrs={"href": lambda x: x and "block_type=pditems" in x}):
-            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:
-            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:
-            return True
-        return False
--- a/PFERD/crawl/ilias/kit_ilias_html.py
+++ b/PFERD/crawl/ilias/kit_ilias_html.py
--- a/PFERD/crawl/ilias/kit_ilias_web_crawler.py
+++ b/PFERD/crawl/ilias/kit_ilias_web_crawler.py
@ -1,23 +1,14 @@
-from typing import Any, Dict, Optional, Union
+from typing import Dict, Literal

-import aiohttp
-import yarl
-from bs4 import BeautifulSoup
-
-from ...auth import Authenticator, TfaAuthenticator
+from ...auth import Authenticator
 from ...config import Config
-from ...logging import log
-from ...utils import soupify
-from ..crawler import CrawlError, CrawlWarning
-from .async_helper import _iorepeat
 from .ilias_web_crawler import IliasWebCrawler, IliasWebCrawlerSection
-
-TargetType = Union[str, int]
+from .shibboleth_login import ShibbolethLogin

 _ILIAS_URL = "https://ilias.studium.kit.edu"


-class KitShibbolethBackgroundLoginSuccessful():
+class KitShibbolethBackgroundLoginSuccessful:
    pass


@ -25,19 +16,8 @@ class KitIliasWebCrawlerSection(IliasWebCrawlerSection):
    def base_url(self) -> str:
        return _ILIAS_URL

-    def client_id(self) -> str:
-        # KIT ILIAS uses the Shibboleth service for authentication. There's no
-        # use for a client id.
-        return "unused"
-
-    def tfa_auth(self, authenticators: Dict[str, Authenticator]) -> Optional[Authenticator]:
-        value: Optional[str] = self.s.get("tfa_auth")
-        if value is None:
-            return None
-        auth = authenticators.get(value)
-        if auth is None:
-            self.invalid_value("tfa_auth", value, "No such auth section exists")
-        return auth
+    def login(self) -> Literal["shibboleth"]:
+        return "shibboleth"


 class KitIliasWebCrawler(IliasWebCrawler):
@ -46,184 +26,12 @@ class KitIliasWebCrawler(IliasWebCrawler):
        name: str,
        section: KitIliasWebCrawlerSection,
        config: Config,
-        authenticators: Dict[str, Authenticator]
+        authenticators: Dict[str, Authenticator],
    ):
        super().__init__(name, section, config, authenticators)

-        self._shibboleth_login = KitShibbolethLogin(
+        self._shibboleth_login = ShibbolethLogin(
+            _ILIAS_URL,
            self._auth,
            section.tfa_auth(authenticators),
        )
-
-    # 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)
-    async def _authenticate(self) -> None:
-        await self._shibboleth_login.login(self.session)
-
-
-class KitShibbolethLogin:
-    """
-    Login via KIT's shibboleth system.
-    """
-
-    def __init__(self, authenticator: Authenticator, tfa_authenticator: Optional[Authenticator]) -> None:
-        self._auth = authenticator
-        self._tfa_auth = tfa_authenticator
-
-    async def login(self, sess: aiohttp.ClientSession) -> 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
-        url = f"{_ILIAS_URL}/shib_login.php"
-        data = {
-            "sendLogin": "1",
-            "idp_selection": "https://idp.scc.kit.edu/idp/shibboleth",
-            "il_target": "",
-            "home_organization_selection": "Weiter",
-        }
-        soup: Union[BeautifulSoup, KitShibbolethBackgroundLoginSuccessful] = await _shib_post(sess, url, data)
-
-        if isinstance(soup, KitShibbolethBackgroundLoginSuccessful):
-            return
-
-        # 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
-            url = "https://idp.scc.kit.edu" + action
-            username, password = await self._auth.credentials()
-            data = {
-                "_eventId_proceed": "",
-                "j_username": username,
-                "j_password": password,
-                "csrf_token": csrf_token
-            }
-            soup = await _post(sess, url, data)
-
-            if soup.find(id="attributeRelease"):
-                raise CrawlError(
-                    "ILIAS Shibboleth entitlements changed! "
-                    "Please log in once in your browser and review them"
-                )
-
-            if self._tfa_required(soup):
-                soup = await self._authenticate_tfa(sess, soup)
-
-            if not self._login_successful(soup):
-                self._auth.invalidate_credentials()
-
-        # Equivalent: Being redirected via JS automatically
-        # (or clicking "Continue" if you have JS disabled)
-        relay_state = soup.find("input", {"name": "RelayState"})
-        saml_response = soup.find("input", {"name": "SAMLResponse"})
-        url = f"{_ILIAS_URL}/Shibboleth.sso/SAML2/POST"
-        data = {  # using the info obtained in the while loop above
-            "RelayState": relay_state["value"],
-            "SAMLResponse": saml_response["value"],
-        }
-        await sess.post(url, data=data)
-
-    async def _authenticate_tfa(
-        self,
-        session: aiohttp.ClientSession,
-        soup: BeautifulSoup
-    ) -> BeautifulSoup:
-        if not self._tfa_auth:
-            self._tfa_auth = TfaAuthenticator("ilias-anon-tfa")
-
-        tfa_token = await self._tfa_auth.password()
-
-        # 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"]
-        csrf_token = form.find("input", {"name": "csrf_token"})["value"]
-
-        # Equivalent: Enter token in
-        # https://idp.scc.kit.edu/idp/profile/SAML2/Redirect/SSO
-        url = "https://idp.scc.kit.edu" + action
-        data = {
-            "_eventId_proceed": "",
-            "j_tokenNumber": tfa_token,
-            "csrf_token": csrf_token
-        }
-        return await _post(session, url, data)
-
-    @staticmethod
-    def _login_successful(soup: 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: BeautifulSoup) -> bool:
-        return soup.find(id="j_tokenNumber") is not None
-
-
-async def _post(session: aiohttp.ClientSession, url: str, data: Any) -> BeautifulSoup:
-    async with session.post(url, data=data) as response:
-        return soupify(await response.read())
-
-
-async def _shib_post(
-    session: aiohttp.ClientSession,
-    url: str,
-    data: Any
-) -> Union[BeautifulSoup, KitShibbolethBackgroundLoginSuccessful]:
-    """
-    aiohttp unescapes '/' and ':' in URL query parameters which is not RFC compliant and rejected
-    by Shibboleth. Thanks a lot. So now we unroll the requests manually, parse location headers and
-    build encoded URL objects ourselves... Who thought mangling location header was a good idea??
-    """
-    log.explain_topic("Shib login POST")
-    async with session.post(url, data=data, allow_redirects=False) as response:
-        location = response.headers.get("location")
-        log.explain(f"Got location {location!r}")
-        if not location:
-            raise CrawlWarning(f"Login failed (1), no location header present at {url}")
-        correct_url = yarl.URL(location, encoded=True)
-        log.explain(f"Corrected location to {correct_url!r}")
-
-        if str(correct_url).startswith(_ILIAS_URL):
-            log.explain("ILIAS recognized our shib token and logged us in in the background, returning")
-            return KitShibbolethBackgroundLoginSuccessful()
-
-        async with session.get(correct_url, allow_redirects=False) as response:
-            location = response.headers.get("location")
-            log.explain(f"Redirected to {location!r} with status {response.status}")
-            # If shib still has a valid session, it will directly respond to the request
-            if location is None:
-                log.explain("Shib recognized us, returning its response directly")
-                return soupify(await response.read())
-
-            as_yarl = yarl.URL(response.url)
-            # Probably not needed anymore, but might catch a few weird situations with a nicer message
-            if not location or not as_yarl.host:
-                raise CrawlWarning(f"Login failed (2), no location header present at {correct_url}")
-
-            correct_url = yarl.URL.build(
-                scheme=as_yarl.scheme,
-                host=as_yarl.host,
-                path=location,
-                encoded=True
-            )
-            log.explain(f"Corrected location to {correct_url!r}")
-
-            async with session.get(correct_url, allow_redirects=False) as response:
-                return soupify(await response.read())
--- a/PFERD/crawl/ilias/shibboleth_login.py
+++ b/PFERD/crawl/ilias/shibboleth_login.py
@ -0,0 +1,129 @@
+from typing import Any, Optional, cast
+
+import aiohttp
+import yarl
+from bs4 import BeautifulSoup, Tag
+
+from ...auth import Authenticator, TfaAuthenticator
+from ...logging import log
+from ...utils import soupify
+from ..crawler import CrawlError
+
+
+class ShibbolethLogin:
+    """
+    Login via shibboleth system.
+    """
+
+    def __init__(
+        self, ilias_url: str, authenticator: Authenticator, tfa_authenticator: Optional[Authenticator]
+    ) -> None:
+        self._ilias_url = ilias_url
+        self._auth = authenticator
+        self._tfa_auth = tfa_authenticator
+
+    async def login(self, sess: aiohttp.ClientSession) -> 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
+        url = f"{self._ilias_url}/shib_login.php"
+        async with sess.get(url) as response:
+            shib_url = response.url
+            if str(shib_url).startswith(self._ilias_url):
+                log.explain(
+                    "ILIAS recognized our shib token and logged us in in the background, returning"
+                )
+                return
+            soup: BeautifulSoup = soupify(await response.read())
+
+        # 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 = cast(Tag, soup.find("form", {"method": "post"}))
+            action = cast(str, form["action"])
+
+            # Equivalent: Enter credentials in
+            # https://idp.scc.kit.edu/idp/profile/SAML2/Redirect/SSO
+            url = str(shib_url.origin()) + action
+            username, password = await self._auth.credentials()
+            data = {
+                "_eventId_proceed": "",
+                "j_username": username,
+                "j_password": password,
+                "fudis_web_authn_assertion_input": "",
+            }
+            if csrf_token_input := form.find("input", {"name": "csrf_token"}):
+                data["csrf_token"] = csrf_token_input["value"]  # type: ignore
+            soup = await _post(sess, url, data)
+
+            if soup.find(id="attributeRelease"):
+                raise CrawlError(
+                    "ILIAS Shibboleth entitlements changed! "
+                    "Please log in once in your browser and review them"
+                )
+
+            if self._tfa_required(soup):
+                soup = await self._authenticate_tfa(sess, soup, shib_url)
+
+            if not self._login_successful(soup):
+                self._auth.invalidate_credentials()
+
+        # Equivalent: Being redirected via JS automatically
+        # (or clicking "Continue" if you have JS disabled)
+        relay_state = cast(Tag, soup.find("input", {"name": "RelayState"}))
+        saml_response = cast(Tag, soup.find("input", {"name": "SAMLResponse"}))
+        url = form = soup.find("form", {"method": "post"})["action"]  # type: ignore
+        data = {  # using the info obtained in the while loop above
+            "RelayState": cast(str, relay_state["value"]),
+            "SAMLResponse": cast(str, saml_response["value"]),
+        }
+        await sess.post(cast(str, url), data=data)
+
+    async def _authenticate_tfa(
+        self, session: aiohttp.ClientSession, soup: BeautifulSoup, shib_url: yarl.URL
+    ) -> BeautifulSoup:
+        if not self._tfa_auth:
+            self._tfa_auth = TfaAuthenticator("ilias-anon-tfa")
+
+        tfa_token = await self._tfa_auth.password()
+
+        # Searching the form here so that this fails before asking for
+        # credentials rather than after asking.
+        form = cast(Tag, soup.find("form", {"method": "post"}))
+        action = cast(str, form["action"])
+
+        # Equivalent: Enter token in
+        # https://idp.scc.kit.edu/idp/profile/SAML2/Redirect/SSO
+        url = str(shib_url.origin()) + action
+        username, password = await self._auth.credentials()
+        data = {
+            "_eventId_proceed": "",
+            "fudis_otp_input": tfa_token,
+        }
+        if csrf_token_input := form.find("input", {"name": "csrf_token"}):
+            data["csrf_token"] = csrf_token_input["value"]  # type: ignore
+        return await _post(session, url, data)
+
+    @staticmethod
+    def _login_successful(soup: 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: BeautifulSoup) -> bool:
+        return soup.find(id="fudiscr-form") is not None
+
+
+async def _post(session: aiohttp.ClientSession, url: str, data: Any) -> BeautifulSoup:
+    async with session.post(url, data=data) as response:
+        return soupify(await response.read())
--- a/PFERD/crawl/kit_ipd_crawler.py
+++ b/PFERD/crawl/kit_ipd_crawler.py
@ -1,8 +1,9 @@
 import os
 import re
 from dataclasses import dataclass
+from datetime import datetime
 from pathlib import PurePath
-from typing import Awaitable, List, Optional, Pattern, Set, Tuple, Union
+from typing import Any, Awaitable, Generator, Iterable, List, Optional, Pattern, Tuple, Union, cast
 from urllib.parse import urljoin

 from bs4 import BeautifulSoup, Tag
@ -31,24 +32,24 @@ class KitIpdCrawlerSection(HttpCrawlerSection):
        return re.compile(regex)


-@dataclass(unsafe_hash=True)
+@dataclass
 class KitIpdFile:
    name: str
    url: str

+    def explain(self) -> None:
+        log.explain(f"File {self.name!r} (href={self.url!r})")
+

@dataclass
 class KitIpdFolder:
    name: str
-    files: List[KitIpdFile]
+    entries: List[Union[KitIpdFile, "KitIpdFolder"]]

    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__()
+        for entry in self.entries:
+            entry.explain()


 class KitIpdCrawler(HttpCrawler):
@ -72,81 +73,96 @@ class KitIpdCrawler(HttpCrawler):

        async with maybe_cl:
            for item in await self._fetch_items():
+                item.explain()
                if isinstance(item, KitIpdFolder):
-                    tasks.append(self._crawl_folder(item))
+                    tasks.append(self._crawl_folder(PurePath("."), item))
                else:
-                    # Orphan files are placed in the root folder
-                    tasks.append(self._download_file(PurePath("."), item))
+                    log.explain_topic(f"Orphan file {item.name!r} (href={item.url!r})")
+                    log.explain("Attributing it to root folder")
+                    # do this here to at least be sequential and not parallel (rate limiting is hard, as the
+                    # crawl abstraction does not hold for these requests)
+                    etag, mtime = await self._request_resource_version(item.url)
+                    tasks.append(self._download_file(PurePath("."), item, etag, mtime))

        await self.gather(tasks)

-    async def _crawl_folder(self, folder: KitIpdFolder) -> None:
-        path = PurePath(folder.name)
+    async def _crawl_folder(self, parent: PurePath, folder: KitIpdFolder) -> None:
+        path = parent / folder.name
        if not await self.crawl(path):
            return

-        tasks = [self._download_file(path, file) for file in folder.files]
+        tasks = []
+        for entry in folder.entries:
+            if isinstance(entry, KitIpdFolder):
+                tasks.append(self._crawl_folder(path, entry))
+            else:
+                # do this here to at least be sequential and not parallel (rate limiting is hard, as the crawl
+                # abstraction does not hold for these requests)
+                etag, mtime = await self._request_resource_version(entry.url)
+                tasks.append(self._download_file(path, entry, etag, mtime))

        await self.gather(tasks)

-    async def _download_file(self, parent: PurePath, file: KitIpdFile) -> None:
+    async def _download_file(
+        self,
+        parent: PurePath,
+        file: KitIpdFile,
+        etag: Optional[str],
+        mtime: Optional[datetime]
+    ) -> None:
        element_path = parent / file.name
-        maybe_dl = await self.download(element_path)
+
+        prev_etag = self._get_previous_etag_from_report(element_path)
+        etag_differs = None if prev_etag is None else prev_etag != etag
+
+        maybe_dl = await self.download(element_path, etag_differs=etag_differs, mtime=mtime)
        if not maybe_dl:
+            # keep storing the known file's etag
+            if prev_etag:
+                self._add_etag_to_report(element_path, prev_etag)
            return

        async with maybe_dl as (bar, sink):
-            await self._stream_from_url(file.url, sink, bar)
+            await self._stream_from_url(file.url, element_path, sink, bar)

-    async def _fetch_items(self) -> Set[Union[KitIpdFile, KitIpdFolder]]:
+    async def _fetch_items(self) -> Iterable[Union[KitIpdFile, KitIpdFolder]]:
        page, url = await self.get_page()
        elements: List[Tag] = self._find_file_links(page)
-        items: Set[Union[KitIpdFile, KitIpdFolder]] = set()

+        # do not add unnecessary nesting for a single <h1> heading
+        drop_h1: bool = len(page.find_all(name="h1")) <= 1
+
+        folder_tree: KitIpdFolder = KitIpdFolder(".", [])
        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:
+            parent = HttpCrawler.get_folder_structure_from_heading_hierarchy(element, drop_h1)
            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
+            current_folder: KitIpdFolder = folder_tree
+            for folder_name in parent.parts:
+                # helps the type checker to verify that current_folder is indeed a folder
+                def subfolders() -> Generator[KitIpdFolder, Any, None]:
+                    return (entry for entry in current_folder.entries if isinstance(entry, KitIpdFolder))

-    def _extract_folder(self, folder_tag: Tag, url: str) -> KitIpdFolder:
-        files: List[KitIpdFile] = []
-        name = folder_tag.getText().strip()
+                if not any(entry.name == folder_name for entry in subfolders()):
+                    current_folder.entries.append(KitIpdFolder(folder_name, []))
+                current_folder = next(entry for entry in subfolders() if entry.name == folder_name)

-        container: Tag = folder_tag.findNextSibling(name="table")
-        for link in self._find_file_links(container):
-            files.append(self._extract_file(link, url))
+            current_folder.entries.append(file)

-        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]$"))
+        return folder_tree.entries

    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 _find_file_links(self, tag: Union[Tag, BeautifulSoup]) -> list[Tag]:
+        return cast(list[Tag], tag.find_all(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"))
+        return urljoin(url, cast(str, link_tag.get("href")))

-    async def _stream_from_url(self, url: str, sink: FileSink, bar: ProgressBar) -> None:
+    async def _stream_from_url(self, url: str, path: PurePath, 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?")
@ -159,6 +175,8 @@ class KitIpdCrawler(HttpCrawler):

            sink.done()

+            self._add_etag_to_report(path, resp.headers.get("ETag"))
+
    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
--- a/PFERD/logging.py
+++ b/PFERD/logging.py
@ -1,9 +1,8 @@
 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
+from contextlib import AbstractContextManager, asynccontextmanager, contextmanager
+from typing import AsyncIterator, Iterator, List, Optional

 from rich.console import Console, Group
 from rich.live import Live
@ -261,7 +260,7 @@ directly or as a GitHub issue: https://github.com/Garmelon/PFERD/issues/new
            action: str,
            text: str,
            total: Optional[float] = None,
-    ) -> ContextManager[ProgressBar]:
+    ) -> AbstractContextManager[ProgressBar]:
        """
        Allows markup in the "style" argument which will be applied to the
        "action" string.
@ -277,7 +276,7 @@ directly or as a GitHub issue: https://github.com/Garmelon/PFERD/issues/new
            action: str,
            text: str,
            total: Optional[float] = None,
-    ) -> ContextManager[ProgressBar]:
+    ) -> AbstractContextManager[ProgressBar]:
        """
        Allows markup in the "style" argument which will be applied to the
        "action" string.
--- a/PFERD/output_dir.py
+++ b/PFERD/output_dir.py
@ -57,6 +57,7 @@ class OnConflict(Enum):

@dataclass
 class Heuristics:
+    etag_differs: Optional[bool]
    mtime: Optional[datetime]


@ -233,8 +234,16 @@ class OutputDirectory:

        remote_newer = None

+        # ETag should be a more reliable indicator than mtime, so we check it first
+        if heuristics.etag_differs is not None:
+            remote_newer = heuristics.etag_differs
+            if remote_newer:
+                log.explain("Remote file's entity tag differs")
+            else:
+                log.explain("Remote file's entity tag is the same")
+
        # Python on Windows crashes when faced with timestamps around the unix epoch
-        if heuristics.mtime and (os.name != "nt" or heuristics.mtime.year > 1970):
+        if remote_newer is None and heuristics.mtime and (os.name != "nt" or heuristics.mtime.year > 1970):
            mtime = heuristics.mtime
            remote_newer = mtime.timestamp() > stat.st_mtime
            if remote_newer:
@ -362,10 +371,28 @@ class OutputDirectory:

        raise OutputDirError("Failed to create temporary file")

+    def should_try_download(
+        self,
+        path: PurePath,
+        *,
+        etag_differs: Optional[bool] = None,
+        mtime: Optional[datetime] = None,
+        redownload: Optional[Redownload] = None,
+        on_conflict: Optional[OnConflict] = None,
+    ) -> bool:
+        heuristics = Heuristics(etag_differs, 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)
+
+        return self._should_download(local_path, heuristics, redownload, on_conflict)
+
    async def download(
            self,
            remote_path: PurePath,
            path: PurePath,
+            *,
+            etag_differs: Optional[bool] = None,
            mtime: Optional[datetime] = None,
            redownload: Optional[Redownload] = None,
            on_conflict: Optional[OnConflict] = None,
@ -375,7 +402,7 @@ class OutputDirectory:
        MarkConflictError.
        """

-        heuristics = Heuristics(mtime)
+        heuristics = Heuristics(etag_differs, 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)
--- a/PFERD/pferd.py
+++ b/PFERD/pferd.py
@ -1,4 +1,4 @@
-from pathlib import Path
+from pathlib import Path, PurePath
 from typing import Dict, List, Optional

 from rich.markup import escape
@ -168,19 +168,24 @@ class Pferd:
            log.report("")
            log.report(f"[bold bright_cyan]Report[/] for {escape(name)}")

+            def fmt_path_link(relative_path: PurePath) -> str:
+                # We need to URL-encode the path because it might contain spaces or special characters
+                link = crawler.output_dir.resolve(relative_path).absolute().as_uri()
+                return f"[link={link}]{fmt_path(relative_path)}[/link]"
+
            something_changed = False
            for path in sorted(crawler.report.added_files):
                something_changed = True
-                log.report(f"  [bold bright_green]Added[/] {fmt_path(path)}")
+                log.report(f"  [bold bright_green]Added[/] {fmt_path_link(path)}")
            for path in sorted(crawler.report.changed_files):
                something_changed = True
-                log.report(f"  [bold bright_yellow]Changed[/] {fmt_path(path)}")
+                log.report(f"  [bold bright_yellow]Changed[/] {fmt_path_link(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)}")
+                log.report_not_deleted(f"  [bold bright_magenta]Not deleted[/] {fmt_path_link(path)}")

            for warning in crawler.report.encountered_warnings:
                something_changed = True
--- a/PFERD/report.py
+++ b/PFERD/report.py
@ -34,15 +34,6 @@ class MarkConflictError(Exception):
        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
@ -173,7 +164,7 @@ class Report:
            if path == other:
                raise MarkDuplicateError(path)

-            if is_relative_to(path, other) or is_relative_to(other, path):
+            if path.is_relative_to(other) or other.is_relative_to(path):
                raise MarkConflictError(path, other)

        self.known_files.add(path)
--- a/PFERD/version.py
+++ b/PFERD/version.py
@ -1,2 +1,2 @@
 NAME = "PFERD"
-VERSION = "3.6.0"
+VERSION = "3.8.0"
--- a/README.md
+++ b/README.md
@ -17,7 +17,7 @@ Binaries for Linux, Windows and Mac can be downloaded directly from the

 ### With pip

-Ensure you have at least Python 3.9 installed. Run the following command to
+Ensure you have at least Python 3.11 installed. Run the following command to
 install PFERD or upgrade it to the latest version:

 ```
--- a/flake.lock
+++ b/flake.lock
@ -2,16 +2,16 @@
  "nodes": {
    "nixpkgs": {
      "locked": {
-        "lastModified": 1708979614,
-        "narHash": "sha256-FWLWmYojIg6TeqxSnHkKpHu5SGnFP5um1uUjH+wRV6g=",
+        "lastModified": 1744440957,
+        "narHash": "sha256-FHlSkNqFmPxPJvy+6fNLaNeWnF1lZSgqVCl/eWaJRc4=",
        "owner": "NixOS",
        "repo": "nixpkgs",
-        "rev": "b7ee09cf5614b02d289cd86fcfa6f24d4e078c2a",
+        "rev": "26d499fc9f1d567283d5d56fcf367edd815dba1d",
        "type": "github"
      },
      "original": {
        "owner": "NixOS",
-        "ref": "nixos-23.11",
+        "ref": "nixos-24.11",
        "repo": "nixpkgs",
        "type": "github"
      }
--- a/flake.nix
+++ b/flake.nix
@ -2,7 +2,7 @@
  description = "Tool for downloading course-related files from ILIAS";

  inputs = {
-    nixpkgs.url = "github:NixOS/nixpkgs/nixos-23.11";
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-24.11";
  };

  outputs = { self, nixpkgs }:
--- a/pyproject.toml
+++ b/pyproject.toml
@ -12,7 +12,7 @@ dependencies = [
  "certifi>=2021.10.8"
 ]
 dynamic = ["version"]
-requires-python = ">=3.9"
+requires-python = ">=3.11"

 [project.scripts]
 pferd = "PFERD.__main__:main"
Author	SHA1	Message	Date
I-Al-Istannen	7291382430	Bump version to 3.8.0	2025-04-15 11:32:22 +02:00
I-Al-Istannen	1a430ad5d1	Update minimum Python version to 3.11	2025-04-15 11:31:39 +02:00
I-Al-Istannen	f6bdeb6b9d	Support ILIAS 9	2025-04-15 11:19:53 +02:00
I-Al-Istannen	63f25277b0	Fix crawling of empty forum threads	2025-03-09 23:44:25 +01:00
I-Al-Istannen	c8eff04ae0	Make thread titles link to original ILIAS thread	2025-02-19 16:23:20 +01:00
I-Al-Istannen	edc482cdf4	Internalize images in forum threads	2025-02-19 16:23:20 +01:00
I-Al-Istannen	72cd0f77e2	Prettify forum thread exports Co-authored-by: Tim <me@scriptim.dev>	2025-02-19 16:23:20 +01:00
I-Al-Istannen	be175f9347	Download only new/updated forum threads	2025-02-19 16:16:37 +01:00
I-Al-Istannen	ba2833dba5	Crawl all threads in a forum Before this patch the row count was unconditionally changed to 800. This patch tries to detect how many rows the forum has and then fetches this amount, if it is larger than 800.	2025-02-19 12:19:33 +01:00
I-Al-Istannen	2f0e792670	Increase default http timeout to 30 Otherwise larger forums will fail to download in time	2025-02-19 12:19:13 +01:00
I-Al-Istannen	5f88539f7e	Fix page size increase for forum threads	2025-02-19 12:19:11 +01:00
I-Al-Istannen	bd9d7efe64	"Fix" mypy errors Thank you mypy, very cool. These types make things so much better. They don't just complicate everything and don't really help because they can not detect that an element queried by a tag is no navigable string...	2025-02-19 12:15:41 +01:00
Aurelia	16a2dd5b15	fix: totp	2025-02-19 12:15:41 +01:00
I-Al-Istannen	678283d341	Use Python facilities to convert paths to file:// urls	2024-11-15 00:09:11 +01:00
I-Al-Istannen	287173b0b1	Bump version to 3.7.0	2024-11-13 20:38:27 +01:00
I-Al-Istannen	712217e959	Handle groups in cards	2024-11-11 12:53:08 +01:00
I-Al-Istannen	6dda4c55a8	Add doctype header to forum threads This should fix mimetype detection on most systems and is more relevant now that the report is clickable	2024-11-05 18:36:21 +01:00
PinieP	596b6a7688	Add support for non-KIT shibboleth login (#98 ) Co-authored-by: Mr-Pine <git@mr-pine.de> Co-authored-by: I-Al-Istannen <I-Al-Istannen@users.noreply.github.com>	2024-11-05 18:30:34 +01:00
Tim	5983200247	Treat headings as folders in kit-ipd crawler (#99 )	2024-11-04 23:53:48 +01:00
Tim	26e802d88b	Add clickable links to file names in the printed report (#100 ) Co-authored-by: I-Al-Istannen <i-al-istannen@users.noreply.github.com>	2024-11-04 00:32:32 +01:00
I-Al-Istannen	f5c4e82816	Delay ilias loop detection after transform This allows users to filter out duplicated elements and suppress the warning.	2024-11-02 22:46:51 +01:00
I-Al-Istannen	f5273f7ca0	Collapse ilias url crawling into normal page crawling	2024-11-02 22:46:51 +01:00
I-Al-Istannen	fa71a9f44f	Add support for mob videos in page descriptions	2024-10-28 20:35:30 +01:00
I-Al-Istannen	81d6ff53c4	Respect row flex in descriptions	2024-10-28 19:41:03 +01:00
I-Al-Istannen	d7a2b6e019	Delete videos from course descriptions	2024-10-28 19:41:03 +01:00
I-Al-Istannen	71c65e89d1	Internalize images in course descriptions	2024-10-28 19:41:03 +01:00
I-Al-Istannen	c1046498e7	Fix download of links without a target URL They are now downloaded as links to the empty url.	2024-10-28 19:41:03 +01:00
I-Al-Istannen	8fbd1978af	Fix crawling of nested courses	2024-10-28 18:52:27 +01:00
Tim	739dd95850	Use Last-Modified and ETag headers to determine KIT-IPD file versions (#95 ) Co-authored-by: I-Al-Istannen <i-al-istannen@users.noreply.github.com>	2024-10-27 19:03:47 +01:00
I-Al-Istannen	c54c3bcfa1	Fix crawling of favorites	2024-10-27 10:50:59 +01:00