[Enhancement] Add link to youtube video on the video error page

[Half-and-Xat]

EDIT by @unixfox

This enhancement is for adding the link to the original youtube.com video on the error page. Like it's already possible when the instance is blocked by youtube.

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The current issue #4584 leads to an error page. This behavior results in a loose of navigation features. The absolute minimum I would expect is a link to the YouTube video page (including embed link). This way Invidious is still useful for searching videos when videos themselves cannot be loaded. It's a must-have improvement in my opinion, especially since it's not the first time that Google break things.

Beyond the minimum: every navigation like link to profile, video successions etc improves the usability even further. I don't know if video downloads are affected by the bug, but if not, those could also be added. These things are more a nice-to-have.

[unixfox]

What do you actually mean by navigation?

When invidious is blocked there is no way to know what is the profile of the video, nor the description and not even the comments.

[Half-and-Xat]

Ah sorry, I'm not familiar with the backend. In this case you can ignore the last two lines of my suggestion. But it would be helpful if the links to YouTube (common video page and embed video page) will be placed on the error page, too. The URL should be known in any case, shouldn't it?

[gbschenkel]

But Invidious have the link which was blocked, is not only take the instance/watch?v=p2Lk3EWwV-I and change it to https://youtube.com/watch?v=p2Lk3EWwV-I ? (used random link video)

[Sommerwiesel]

The feature is already (somewhat) implemented.
Just use the "try another instance" link on the error page which will lead you to the redirection page which has, in fact, at the very top, a direct link to youtube.

https://redirect.invidious.io/watch?v=jNQXAC9IVRw

Yes, this is one additional click, but good enough imo.

[syeopite]

I remember that a couple years ago the error page did have a "Try using YouTube instead" link, but it looks like it got lost with the various changes since then

[SamantazFox]

@syeopite only the most basic error page (triggered by an InfoException) has it:

[Half-and-Xat]

And what is the argument against doing it better? Does it hurt to have it directly on error page? I don't think so.

Keep in mind that Invidious is not just for people like us, people who know how to use URLs correctly, people who are able to trial and error to find the embed version of YouTube (like youtube.com/e/p2Lk3EWwV-I or youtube.com/embed/watch?v=p2Lk3EWwV-I or youtube.com/embed/p2Lk3EWwV-I). If I send a link to other people who usually don't use Invidious, they may don't even know that they just need to replace instance.domain/watch?v=p2Lk3EWwV-I with youtube.com/watch?v=p2Lk3EWwV-I`` or to click on "other instances" to get the YouTube link (even I did not realize that there was a link, too).

@SamantazFox: Even here, Go to YouTube (Embed) (2 links) would be a little improvement. I agree with unifying it.

[unixfox]

Link was added in https://github.com/iv-org/invidious/pull/4650/files#diff-3919f4375b028c051402e6e79ae426d16da8fc4db65b4dfa945c384d00132870R150 by switching to InfoException.