Images in post take a long time to appear

[NFG]

I've recently noticed that images added inline to a post will show up as 404 for about five minutes after the post is made.  I assume there's a background process at work that's making the thumbnails and whatever, but I would like to know what's the trigger for this process, and is there a way I can trigger it manually?

Because if I don't share that new post's link as soon as the post is made, I'll forget that it exists by the time the images are ready. 

Thanks for any clues or advice. 

[Sesquipedalian]

No, attachment processing does not happen in a background task. SMF fully processes all attachments when the post is submitted. By the time you see the page reload after clicking the submit button, SMF is done with it.

The symptoms you are describing strongly suggest that something else on your server is interfering after SMF has finished processing the attachments. (After all, the very fact that SMF is trying to show the image attachment in your post demonstrates that SMF thinks it is supposed to be there.)

Our friendly support volunteers will likely be here soon to ask you questions to help you figure out what might be causing this. They've seen a lot of weird stuff over the years, so they're good at sniffing out oddities.

[Aleksi "Lex" Kilpinen]

One thing worth checking, is it really 5 minutes or would a simple hard refresh after posting help? I remember seeing forums where the image just would not come up immediately, but a second page load (by anyone) already works. Not sure if it's some sort of race condition or what, just something I've seen.

[Kindred]

Server cache or browser cache - probably

[NFG]

is it really 5 minutes or would a simple hard refresh after posting help?

The fact that I can send the link to a friend in Norway and he can't see the images either definitely suggests it's not something a hard refresh will fix.  It might not have been five minutes exactly but it was way more than one minute and probably pretty close to five by the time they all worked.

Server cache or browser cache

There is no cache on the server, it's a standard nginx + PHP7.4 setup.  If there's any kind of caching going on I can't imagine where it came from or how it works, or how it only affects SMF. 

The error shown when an image is clicked is a very simple, text-only '404: Not Found' (or similar, I didn't write it down).  It's not a server 404 page, it's coming from SMF.  The URL being requested is:

Code Select Expand

https://---/index.php?action=dlattach;attach=4541;image

[shawnb61]

This is a longshot, but...

In a recent support request, the proxy was intercepting requests and displaying the single-line WSOD 'File not found', instead of passing the request on.

Turns out that single-line message is the proxy's standard 404 page.  (Not Apache's...)

If the proxy is confusing the request with a filename, that might explain it.

The other issue was resolved with:

Code Select Expand

ProxyErrorOverride On...in the apache config.

Other issue:  https://www.simplemachines.org/community/index.php?topic=591391.0

[NFG]

Turns out that single-line message is the proxy's standard 404 page.  (Not Apache's...)

Yeah but I'm running nginx.

To be clear, this is my server, it's my whole computer built from the ground up, there's nothing running on that Ubuntu Server box that I didn't put there.  If there's any kind of proxy between nginx and PHP and SMF then I have no idea what it is or how it got there, and I'd really really like to know how such a thing could happen.

But that said, maybe there's some sort of built-in proxy capability?  But I'd expect to see an 'nginx proxy' error, not this vague thing.

[shawnb61]

But that said, maybe there's some sort of built-in proxy capability?

Looks like it defaults to on:
https://nginx.org/en/docs/http/ngx_http_proxy_module.html

[NFG]

Looks like it defaults to on:
https://nginx.org/en/docs/http/ngx_http_proxy_module.html

Yeah, nginx includes a proxy service by default, but it's not ON unless you turn it on.  I use it for apps that require it, like webcams, music streamers, and the like.  It's not used for things like standard webpages, and I don't use it for any services on the domain in question.

[NFG]

At this point it does seem like you've answered my question: it's not SMF that's doing it.

I guess I'm just going to have to wait until it happens again and kick its ass somehow.

[shawnb61]

Yeah, as Sesq said above, the SMF transaction is synchronous.  Once the post is done, the attachments should be available.

If SMF tries to load an attachment that doesn't exist, you can see a similar one-line message.  I'd be tempted to modify SMF's text... If you see that modified text, you'd know for certain that's an SMF message, & not from another component.

If confirmed it's an SMF message, we'll, that'd be interesting...  What would make the db say "I got it" then later say "nope"...  In that case, I'd look closely at the db...