Automatic thumbnails for Textpattern

etc · Today 19:45:20

Bloke wrote #341836:

EDIT: is that to do with the location of the redirect in the serveRenderedImage() method? Was it better in serveFile()? I dunno.

There should be no difference, serveFile() just set some headers. What if you try TEXTPATTERN_THUMB_TTL = 0?

Bloke · Today 20:04:48

etc wrote #341837:

What if you try TEXTPATTERN_THUMB_TTL = 0?

With a 308, no difference. In fact, first time I tried it was worse! Txp only generated the first handful of thumbs – like, 5 or 6, due to lazy loading, and when I scrolled down the page, the rest remained unrendered. ~~But for some reason when I tried it a second time, it rendered them all so maybe something was still cached somehow.~~ Nope, scratch that. I was at the bottom of the page. When I scrolled up, the thumbnails out of viewport didn’t get rendered.

However, a 307 or 302 and TTL=0 is better. Presumably that will refetch them every request, right, so invalidating any browser cache?

Last edited by Bloke (Today 20:11:38)

Bloke · Today 20:20:01

I did have some weirdness a moment ago. When I navigated to page 2 on the Images panel, none of the thumbs were regenerated. I had to force refresh. After that, when I visited page 2 after clearing the cache, the thumbs were regenerated. My best guess is that the entire page 2 was in the browser cache and it thought nothing had changed so it never hit the server at all.

Side annoyance: Using Ajax pagination means it’s no longer possible/easy witout hacking the URL to pass links around that go to specific pages of results. If I navigate to page 2 of the Images panel results and hit Refresh, it dumps me back on Page 1 because that’s what the URL dictates. It was much better when the URL had the ?pg= and/or ?q= in it

*sigh* That’s progress I guess.

etc · Today 20:20:11

Yep, I have unset cache-control header, leaving it with the browser, please retest. No need for TTL=0 a priori.

etc · Today 20:21:41

Bloke wrote #341839:

My best guess is that the entire page 2 was in the browser cache and it thought nothing had changed so it never hit the server at all.

I bet yes, but this is not thumbnails-specific.

Bloke · Today 20:46:30

That’s much better on localhost. But on my server (front-end and back-end) I get some missing images on refresh. I have to force refresh to get them all to show.

And after I delete the cache, I need to force refresh again to get them all to show up. Random pictures down the page just don’t load and the Inspector reports “Could not load this image”. Here’s a typical request:

GET /images/thumb/w180-h150-c4x3.topcentered-q80-baa3071/186.jpg HTTP/2
Host: example.com
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:146.0) Gecko/20100101 Firefox/146.0
Accept: image/avif,image/webp,image/png,image/svg+xml,image/*;q=0.8,*/*;q=0.5
Accept-Language: en-GB,en;q=0.5
Accept-Encoding: gzip, deflate, br, zstd
Referer: https://example.com/textpattern/index.php?event=image
Connection: keep-alive
Cookie: PHPSESSID={key-here}
Sec-Fetch-Dest: image
Sec-Fetch-Mode: no-cors
Sec-Fetch-Site: same-origin
If-Modified-Since: Fri, 19 Dec 2025 20:33:12 GMT
Priority: u=4, i
TE: trailers

And response headers:

HTTP/2 200 
cache-control: no-cache, no-store, max-age=0
vary: Accept-Encoding
content-encoding: br
content-length: 1
content-type: text/html; charset=utf-8
date: Fri, 19 Dec 2025 20:34:15 GMT
server: Apache
X-Firefox-Spdy: h2

The inspector reports it sent 289 bytes back to me. Hardly a full image 🤔

Interestingly, if I copy one of the “broken” thumbnail URLs with its ?token= and paste it into a new browser tab and hit Enter, it immediately redirects to the non-tokenised version, which of course fails to load because the token has been omitted and the system thinks I’m hacking. If I turn off security, all images load, on both admin and public sides.

Bloke · Today 20:57:46

As an aside, can I just say I’m impressed with the smart cropper. I’ve no idea how the (complex) voodoo inside the class works but if you download this sample set of landscape/portrait images, try this:

In your Admin Theme prefs, set your thumbs to 240 x 200 with a crop = 4x3.
Visit your Images panel and upload some of the Portrait images from that set.
Note the auto-generated thumbnails are centered, with the number slap bang in the middle and the boy’s torso visible. Because centered crop is default.
Revisit your Admin Theme prefs and change the crop value to 4x3:smart.
Return to your Images panel and look at the thumbs it regenerates. Note the boy in the pic is now the main focus, and the number is towards the top of the image.

Very cool for automatic art direction! It’s not perfect, but (if it can find a subject) it makes a pretty good guess where it is.

Other samples that work quite well and show off the dynamic nature of the smart cropper:

Last edited by Bloke (Today 21:25:33)

etc · Today 21:23:35

Bloke wrote #341842:

Interestingly, if I copy one of the “broken” thumbnail URLs with its ?token= and paste it into a new browser tab and hit Enter, it immediately redirects to the non-tokenised version

Seemingly, your browser has decided to keep 307 redirect in cache for some time. What if you set

'Cache-Control' => 'no-store, no-cache, must-revalidate, max-age=0'

in serveRenderedImage()?

Bloke · Today 21:35:05

etc wrote #341844:

'Cache-Control' => 'no-store, no-cache, must-revalidate, max-age=0'...

Bingo.

EDIT: Ach, wait no. I had security off.

Last edited by Bloke (Today 21:42:00)

Bloke · Today 21:52:27

Okay, mostly bingo.

On the public side I still get random holes in my page full of images. Worse, I can’t right click an image, grab its tokenized content and paste it into the browser to render it because the (aggressive?) browser cache redirects to the no-token version. I have to force refresh once or twice to make them all render, and then it works.

Once I’ve done that, if I subsequently clear the cache and regular (not force) refresh, the browser behaves and loads all images, seemingly all the time.

So, presumably it had some “old” requests still cached and it tried to serve those at first unti I’d force-refreshed it into forgetting them all!

For anyone using this for the first time, I expect they’ll have no issues. It’s only my old browser cache that was maybe tainting the experience.

So, a tentative thumbs up for the hard no-cache, no-age, no-everything Cache-Control header..

Last edited by Bloke (Today 21:53:40)

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#241 Today 19:45:20

Re: Automatic thumbnails for Textpattern

Bloke wrote #341836:

#242 Today 20:04:48

Re: Automatic thumbnails for Textpattern

etc wrote #341837:

#243 Today 20:20:01

Re: Automatic thumbnails for Textpattern

#244 Today 20:20:11

Re: Automatic thumbnails for Textpattern

#245 Today 20:21:41

Re: Automatic thumbnails for Textpattern

Bloke wrote #341839:

#246 Today 20:46:30

Re: Automatic thumbnails for Textpattern

#247 Today 20:57:46

Re: Automatic thumbnails for Textpattern

#248 Today 21:23:35

Re: Automatic thumbnails for Textpattern

Bloke wrote #341842:

#249 Today 21:35:05

Re: Automatic thumbnails for Textpattern

etc wrote #341844:

#250 Today 21:52:27

Re: Automatic thumbnails for Textpattern

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