Topic List Thumbnails

gdude2002 · May 7, 2022, 9:27pm

I’ve attempted to set this up here, but thumbnails don’t seem to actually be generating for our topics.

Is this in any way tied to the editing grace period setting? The Topic List Previews theme component doesn’t get thumbnails until the first post is no longer editable, either — but this category does not suit that approach at all, and we’d prefer that users are able to edit their posts indefinitely in this category.

merefield · May 8, 2022, 6:00am

Correct.

As front end mods only, Topic List Thumbnails & Topic List Previews leverage the same core process that generates thumbnails in the back end. That async job is not run until the editing grace period is over UPDATE: if the image is remote. If the images are uploaded locally the thumbnail generation process is kicked off straightaway.

The process is not modifiable by a Theme Component and would require a plugin or PR to the back end to change (not withstanding that TLP has a complementary plugin for some added features)

Note before thumbnail support was added to core, Topic List Previews was a plugin and worked in much the same way in terms of scheduling the creation of thumbnails. I can’t speak for the team but you can understand the logic of keeping it that way: you don’t want to be generating thumbnails whose source image might be frequently edited out or what if an image is added at last minute?

One way you can mitigate it is use the default icon/image feature in each theme component respectively. For masonry/tiles view this at least reduces dramatic changes in layout. Or minimise the grace period?

gdude2002 · May 8, 2022, 10:40am

Ah, yeah, I see. It makes total sense for that to be the default behaviour — we’re in a tricky spot here because much of what will be posted in this category will be Minecraft mods, so it stands to reason that the first post in any topic will need to be edited infrequently, and the thumbnail is likely to be changed.

I assume you’re not aware of any plugins that allow you to change this behaviour, off the top of your head? I can see why Core doesn’t support this, but relying on the grace period just isn’t going to work for us.

merefield · May 8, 2022, 3:12pm

No, I don’t think so. The closest thing was the old deprecated topic list previews plugin that you could have modified.

You either need to do this work yourself or marketplace

gdude2002 · May 8, 2022, 3:12pm

Alright, no worries, thanks for your time!

merefield · May 8, 2022, 3:14pm

Just to add though, a significant part of the battle is actually specifying the exact practical behaviour you want that will work in all edge cases. Then follow up with the work, ie make sure what you want will work in practice. It’s all modifiable. :).

If the post changes past the deadline I believe the system should schedule a another pull and update the thumbnail.

gdude2002 · May 8, 2022, 4:31pm

I think I may have been getting confused between the grace period and editing lockout, because as of a short while ago, thumbnails have just kinda started generating.

I think maybe I need to attribute that to a CDN caching mistake, haha. Still, thanks for your help!

merefield · May 8, 2022, 4:33pm

Oh, yes, I’ve heard that happen, fantastic!

There was some related confusion going on here too, in this issue

th21 · May 9, 2022, 4:44am

looks like it’s broken after the latest commit, test on theme-creator with gird tags.

merefield · May 9, 2022, 5:49am

That could be a lot of things. Do you have an error in the JavaScript console?

th21 · May 9, 2022, 6:02am

Yes

merefield · May 9, 2022, 6:14am

Gareth, apologies for confusion, but now I’m back at my desk, I’ve done some quick testing and review of the logic.

My statement was incomplete:

If the image is remote in any way (including onebox of remote link, when it is held in a CDN?) the thumbnails are impacted by a delayed job: Jobs::PullHotlinkedImages and this is indeed scheduled after the editing grace period (this part was correct):

github.com

discourse/discourse/blob/c1db968740d6177d28f80599afb2f7961aca9638/spec/lib/cooked_post_processor_spec.rb#L1583

      
        
              expect(Jobs::PullHotlinkedImages.jobs.size).to eq(0)
            end
            
            
context "and there is enough disk space" do
              before { cpp.expects(:disable_if_low_on_disk_space).at_least_once }
            
            
  context "and the post has been updated by an actual user" do
            
            
    before { post.id = 42 }
            
            
    it "ensures only one job is scheduled right after the editing_grace_period" do
                  freeze_time
            
            
      Jobs.expects(:cancel_scheduled_job).with(:pull_hotlinked_images, post_id: post.id).once
            
            
      delay = SiteSetting.editing_grace_period + 1
            
            
      expect_enqueued_with(job: :pull_hotlinked_images, args: { post_id: post.id }, at: Time.zone.now + delay.seconds) do
                    cpp.pull_hotlinked_images
                  end
                end

BUT: it appears if you upload an image directly to the site (e.g. by pasting an image), the thumbnails are created in an async process which appears to be kicked off immediately. If you update the image to another local image, this will also be reflected almost immediately. I’ve updated a couple of Posts above. Because I don’t do this very often, I’d omitted this part.

gdude2002 · May 9, 2022, 8:45am

Huh, okay, that’s fascinating behaviour, but it makes sense to me, I think.

That’s very useful info, I can update my posting guidelines then. Thanks for the clarification!

jtooker · May 9, 2022, 4:19pm

Bug

If I have the Topic Thumbnails theme component enabled, it breaks my forum. I am at 2.9.0.beta4 [222c8d9b6a]. I am using the graceful theme.

Disabling the Topic Thumbnails theme component unbreaks my forum, but of course now topic thumbnails do not appear.

I created this bug post but someone recommended I post here since the bug is not with the forum itself.

merefield · May 9, 2022, 4:54pm

Does this also happen with Topic List Previews? If so might be a bug in core …

jtooker · May 9, 2022, 5:59pm

No, that worked. I just installed it to test and did not configure anything non-default, but it seemed to apply and work properly.

undasein · May 9, 2022, 6:14pm

Yeah, component broken in my forums too

tkearsley · May 9, 2022, 7:07pm

This is also broken in our forums.

awesomerobot · May 9, 2022, 7:40pm

@jtooker, @undasein I’ve just added a fix, updating the component should solve it (@tkearsley your site should already be updated).

Thanks for reporting it everyone!

jtooker · May 9, 2022, 7:42pm

Thanks! It worked just fine.

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