hono4kami
All of the people who are happy with the fediverse just stay here and participate without writing a navel-gazing “review.”
This is probably a language-barrier on my part, so sorry if I misunderstood your comment, but I also included comments that are originated from Lemmy, or wedistribute.org a website that supports the fediverse movement
OOT, is this post shows up as cross-posted? I think it doesn't
My Lemmy instance actually can't fetch YouTube thumbnail, so I actually have to put it manually lol.
If you don't put a whopping 1MB of JavaScript in your website, you're doing web development wrong.
/s
See the other reply: seems that it was caused by Lemmy backend only fetches the first 512kb of the HTML, meanwhile YouTube puts bunch of JavaScript in the beginning of the HTML
Here's the fix that was only merged couple days ago apparently, https://github.com/LemmyNet/lemmy/pull/5266
Crazy, right
Also, this is a good tip in general:
You can't fetch title and thumbnail for YouTube links that starts with youtu.be. This applies not only in Lemmy, but other websites too, for example Twitter (even before Elon's era).
This is, IMO due to the link doesn't really contain HTML and OpenGraph metadata. It only redirects you. If you try cURL-ing the youtu.be link, you will see that it doesn't have a response body, only some header including Location header that will tell you where to redirect. The response code itself is 301.
So I take a peek at the Lemmy's source code.
When you see a thumbnail and title of a URL (including YouTube video links) on Lemmy, what happens is that Lemmy server fetched the website HTML file and get the og:title and og:image (this convention is called OpenGraph protocol ^1) located inside <head> HTML tag.
For example, for this video https://www.youtube.com/watch?v=MbYuEEU5e50, the OpenGraph metadata inside the HTML looks like this:
<meta property="og:title" content="Flume - Lose It feat. Vic Mensa">
<meta property="og:image" content="https://i.ytimg.com/vi/MbYuEEU5e50/maxresdefault.jpg">
Try opening the "Create Post" page, then enter URL of a YouTube video. You might notice that a loading spinner will appear. During this, the frontend of Lemmy is actually creating a request to /api/v3/post/site_metadata?url=[insert your URL]. When the backend side of Lemmy receives the request from front end, it will run this code ^2 to fetch the HTML and parse it to find the OpenGraph metadata. If the metadata is found, the backend will return it to front end, and you willl see recommended title and the "Thumbnail URL" field should be filled.
In theory, this should work fine, regardless of any website. I personally tried to view the HTML code of a YouTube video and the HTML file indeed contains OpenGraph metadata.
But it doesn't for YouTube videos in Lemmy somehow. And I'm not sure.
I'm suspecting YouTube thought that Lemmy servers are bots and because of that instead of receiving the HTML file of a YouTube video, instead it received a HTML file of a captcha page. I think I'm gonna try contacting admins of my instance to see whether YouTube URL works or not.
It's because Lemmy can't fetch YouTube thumbnails. I swear it used to fetch thumbnail and title automatically before, hmm
Yeah don't do that