Now youtubeDlCheck downloads the beginning of the url's content and
checks if it's html, only when it is does it pass it off the youtube-dl
to check if it supports it.
This means more work is done for urls that youtube-dl does support,
but is probably more efficient for other urls, since it only downloads
the first chunk of content, while youtube-dl probably downloads more.
As well as the reported bug, this also fixes behavior when an url
was added with youtube-dl, but the url content has now changed from
a html page to something else. Remote.Web.checkKey used to wrongly
succeed in that situation, since youtube-dl said sure it can download
that something else.
This commit was supported by the NSF-funded DataLad project.
This will be used in youtube-dl integration, to tell when a html page has
been downloaded by addurl, in which case it is worth running youtube-dl
to see if it can extract media from it.
tagsoup is an almost free dependency, because yesod depends on it.
So, this only really adds a dep when git-annex is built without the
webapp.
I'd like this to as closely as possible match how browsers decide if a
page is html or not. Unfortunately, that is fairly heuristic, in order
to support malformed html. And, we don't want to falsely detect
something as html just because it has something that looks like a html
tag embedded somewhere in it. Probably any major video hosting site is
going to be serving html documents that at least start with a <html>
tag, so requiring that or a DOCTYPE should be good enough.
This commit was sponsored by Jeff Goeke-Smith on Patreon.
