Youtube captions (link previews) are useless

[eras]

Description

At some point Youtube has updated the site and now all (?) captions generated by Synapse for the site are:

Before you continue to YouTube
Sign in a Google company Before you continue to YouTube Google uses cookies and data to: Deliver and maintain services, like tracking outages and protecting against spam, fraud, and abuse Measure audience engagement and site statistics to understand how our services are used

This is basically useless considering the primary point of the function, in particular in the case of a very popular website.

Steps to reproduce

• send a Youtube URL m.room.message into a room, e.g. https://www.youtube.com/watch?v=RzJf02TIqxk
• wait for Synapse to produce a caption for the link
• witness the caption to contain no information about the actual link :)

Expected results:

• A descriptive message about the contents, such as the one produced by an up-to-date youtube-dl --get-description:

Authentic recordings from inside Hetzner Online's data center park
Just like birds and insects, each server sings its own unique song.

Version information

• Homeserver: matrix.org

[ShadowJonathan]

(FTR: This is about link previews)

This is not neccecarily a problem with synapse, synapse is doing it's job perfectly by previewing the url as-is fetched, because matrix.org's server is located within the EU, Google has a tendency (heh) to present users with the cookie page before letting them access any part of the site, by law.

[ShadowJonathan]

https://meta.discourse.org/t/youtube-embeddings-have-stopped-working-for-servers-in-europe/185128

🤔

[eras]

I agree that it's not particularly a bug in Synapse; however the only parties able to resolve this issue are Google and Synapse (or the 3rd party component it's using), and I have my doubts about Google doing anything about it :).

IIRC e.g. Slack doesn't have this issue, so it's resolvable; even if with special handling.

[eras]

For one plausible solution consider the following session:

% curl -s -A Mozilla -I https://www.youtube.com/watch?v=RzJf02TIqxk | grep -e '^HTTP' -e '^location'
HTTP/2 302 
location: https://consent.youtube.com/m?continue=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DRzJf02TIqxk&gl=FI&m=0&pc=yt&uxe=23983172&hl=fi&src=1

% curl -s -I https://www.youtube.com/watch?v=RzJf02TIqxk | grep -e '^HTTP' -e '^location'        
HTTP/2 200 

[richvdh]

ohh bother. we had this with twitter (#7643).

It looks like we should do the same trick as we did with them (hardcode a mapping to the oembed api):

$ curl -A Mozilla 'https://www.youtube.com/oembed?url=https%3A//www.youtube.com/watch%3Fv%3DRzJf02TIqxk&format=json' 
{"title":"PURE RELAXATION - SERVER SOUNDS","author_name":"Hetzner","author_url":"https://www.youtube.com/c/HetznerOnline","type":"video","height":113,"width":200,"version":"1.0","provider_name":"YouTube","provider_url":"https://www.youtube.com/","thumbnail_height":360,"thumbnail_width":480,"thumbnail_url":"https://i.ytimg.com/vi/RzJf02TIqxk/hqdefault.jpg","html":"\u003ciframe width=\u0022200\u0022 height=\u0022113\u0022 src=\u0022https://www.youtube.com/embed/RzJf02TIqxk?feature=oembed\u0022 frameborder=\u00220\u0022 allow=\u0022accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture\u0022 allowfullscreen\u003e\u003c/iframe\u003e"}

[alturiak]

I guess, this will be affecting an increasing number of (less high-profile) sites as well, such as https://www.golem.de (a german news-portal). Hardcoding exceptions for youtube is certainly warranted - but in the long run, it might be nice to be able to specify custom hooks in synapse's configuration, although I'm not sure if that's really worth the effort.

[clokep]

it might be nice to be able to specify custom hooks in synapse's configuration, although I'm not sure if that's really worth the effort.

This shouldn't be too hard, it would also be nice to default to using the documented providers (https://oembed.com/providers.json).

[ShadowJonathan]

This shouldn't be too hard, it would also be nice to default to using the documented providers (https://oembed.com/providers.json).

Oooo, thanks for mentioning that, shouldn't that just be preloaded and used directly when URL previews are enabled?

[clokep]

This shouldn't be too hard, it would also be nice to default to using the documented providers (oembed.com/providers.json).

Oooo, thanks for mentioning that, shouldn't that just be preloaded and used directly when URL previews are enabled?

It should probably be tried. I don't know if it will regress other previews. 🤷

[licentiapoetica]

also on Hetzner, experiencing the same issue

[ItsCinnabar]

If anyone wants a temporary user sided fix for themselves, I made this tampermonkey script : https://gist.github.com/ItsCinnabar/ebcfe4f6b3ea7d224a8e1ef0783edeb2

Just edit the match url to your site and load it into tampermonkey/greasemonkey/etc