We are using Topic List Previews (legacy) with tiles in our main page . Yesterday we had to rebuild our instance for reasons unrelated to TPL. We were aware of the change of thumbnailing backend in Discourse core and we knew that upgrading could cause problems with thumbnails. Still, it had to be don…

As discussed, thumbnailing production logic is now built into core. What TLP used to have to do is no longer necessary, largely. For reference, the core criteria for inclusion are the following: def extract_images_for_post # all images with a src attribute @doc.css("img[src]") - # m…

Thank you @merefield , this is very informative. I just want to say that the previous thumbnailing of Soundcloud oneboxes provided great results, and this regression is really bothering for a site focusing on music like ours. :slight_smile: I don’t mind if we miss a YouTube thumbnail here and ther…

[afbeelding] icaria36: There is one (and only one, the last one) topic with a YouTube onebox that won’t generate a thumbnail, no idea why At a glance, I don’t think that’s a YouTube onebox. I suspect someone has used raw YouTube embedding code in the post. If you turn it into a onebox, the th…

Yes, there was some custom logic around oneboxes, though this was not exclusively for SoundCloud: if @has_oneboxes cooked = PrettyText.cook(@post.raw) if img ## We need something more specific to identify the image with img_id = img src = img.attribute("src"…

[afbeelding] david: At a glance, I don’t think that’s a YouTube onebox . I suspect someone has used raw YouTube embedding code in the post. If you turn it into a onebox, the thumbnail should work. Ah, it didn’t occur to me to check the source. :slight_smile: It was a onebox, but the URL had …

[afbeelding] icaria36: It was a onebox, but the URL had an extra argument Interesting, I’ll take a look at this next week. I think it should still work, even with an extra argument [afbeelding] merefield: custom logic around oneboxes Ah I see, so you pulled the Onebox preview html, an…

Yes, this is based on @angus ’ marvellous hack :smiley: I take no responsibility! Works well though. UPDATE Actually, I lie, my finger prints are also all over it too! I wrote some of this code so long ago I’d forgotten about it, 2015! https://github.com/paviliondev/discourse-topic-previews/comm…

I had the same problem with https://youtu.be/ style youtube links. After changing them to https://www.youtube.com/watch?v= style it worked again.

That’s odd, can you share those specific youtube links here? Either form should work.

Maybe a re-render would have done the job as well. But it seems to live on in the versions: [example] I did reset the link to the old one, but now everything renders nicely. I guess that this was due to a rendering error after the beta6 update.

Problems with thumbnails from Soundcloud and YouTube oneboxes

Ondersteuning

david (David Taylor) 1 juni 2020 om 09:15 10

These are both tricky problems, and I think for now we will be leaving the behavior as-is. We may be able to add some improvements in future. I created a couple of Contribute > Feature topics to track progress

For the YouTube difference, see:

For the soundcloud issue, see:

Topic		Antwoorden	Weergaven
Issue with Onebox and Youtube Bug onebox	10	1260	20 augustus 2019
Thumbnails for iframe oneboxes Feature	1	774	14 september 2020
Using onebox images for topic thumbnails Development	27	3281	27 februari 2022
Thumbnails are missing for our external embeds when using topic-thumbnails Development pr-welcome	10	1111	31 maart 2023
YouTube URIs fail to render thumbnails when oneboxed Bug composer , onebox	11	361	12 november 2025

Problems with thumbnails from Soundcloud and YouTube oneboxes

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