ilias crawler: Use direct download link if possible

This commit is contained in:
I-Al-Istannen 2020-04-23 13:07:07 +02:00
parent 4b59a7c375
commit c2b14f3db9

View File

@ -225,6 +225,10 @@ class IliasCrawler:
{"limit": 800, "cmd": "asyncGetTableGUI", "cmdMode": "asynch"}
)
direct_download_links: List[bs4.Tag] = video_list_soup.findAll(
name="a", text=re.compile(r"\s*Download\s*")
)
# Video start links are marked with an "Abspielen" link
video_links: List[bs4.Tag] = video_list_soup.findAll(
name="a", text=re.compile(r"\s*Abspielen\s*")
@ -232,17 +236,25 @@ class IliasCrawler:
results: List[IliasDownloadInfo] = []
# We can download everything directly!
if len(direct_download_links) == len(video_links):
for link in direct_download_links:
results += self._crawl_single_video(video_dir_path, link, True)
else:
for link in video_links:
results += self._crawl_single_video(video_dir_path, link)
results += self._crawl_single_video(video_dir_path, link, False)
return results
def _crawl_single_video(self, parent_path: Path, link: bs4.Tag) -> List[IliasDownloadInfo]:
def _crawl_single_video(
self,
parent_path: Path,
link: bs4.Tag,
direct_download: bool
) -> List[IliasDownloadInfo]:
"""
Crawl a single video based on its "Abspielen" link from the video listing.
"""
video_page_url = self._abs_url_from_link(link)
# The link is part of a table with multiple columns, describing metadata.
# 6th child (1 indexed) is the modification time string
modification_string = link.parent.parent.parent.select_one(
@ -255,11 +267,23 @@ class IliasCrawler:
).getText().strip()
title += ".mp4"
video_path: Path = Path(parent_path, title)
# The video had a direct download button we can use instead
if direct_download:
LOGGER.debug("Using direct download for video %r", str(video_path))
return [IliasDownloadInfo(
video_path,
self._abs_url_from_link(link),
modification_time
)]
# Fetch the actual video page. This is a small wrapper page initializing a javscript
# player. Sadly we can not execute that JS. The actual video stream url is nowhere
# on the page, but defined in a JS object inside a script tag, passed to the player
# library.
# We do the impossible and RegEx the stream JSON object out of the page's HTML source
video_page_url = self._abs_url_from_link(link)
video_page_soup = self._get_page(video_page_url, {})
regex: re.Pattern = re.compile(
r"({\"streams\"[\s\S]+?),\s*{\"paella_config_file", re.IGNORECASE
@ -276,7 +300,7 @@ class IliasCrawler:
# and fetch the video url!
video_url = json_object["streams"][0]["sources"]["mp4"][0]["src"]
return [IliasDownloadInfo(Path(parent_path, title), video_url, modification_time)]
return [IliasDownloadInfo(video_path, video_url, modification_time)]
def _crawl_exercises(self, element_path: Path, url: str) -> List[IliasDownloadInfo]:
"""