Click twice on each attachment to download [SITE-BUG]

[Nepster]

Whenever I want to download an attachment, I have to try that twice: After the first click I always get the error "The requested URL /index.php was not found on this server." The second try then works fine.

[Forestidia86]

This has occurred to me more often as well recently. I think it was mainly picture-attachments.

[Simon]

Can reproduce on Linux with Firefox 57.0.4 with the image attachments in thread "graphic set additions".

• First click on attachment generates error page.
  
• Reloading the error page (alternatively, back button and second click on attachment) page serves the file.
  
• Other attachments in the same thread still require two clicks (or one click plus reload) even when we have already downloaded another attachment from the same thread.
  

-- Simon

[namida]

I have noticed this occasionally in the past, assumed it was a random glitch. Until this thread, I had not found any example that reproduces the issue consistently.

[ccexplore]

I think it's because the issue seems specific to image attachments.  I can't reproduce this with non-image attachments, but can consistently repro with image attachments from a few threads I've just tried.  Maybe there are now more image attachments (eg. recent threads on tilesets and such) so the bug becomes more noticeable?

I found that with image attachments, the bug seems to be that the download link alternates between the 404 and the success states.  Just pick a suitable download URL and retry it multiple times (you don't have to download, you can cancel it at the point the browser asks you whether you want to download or not, if your browser is configured to prompt first).  This state seems to be per link--if you try it with two different download links alternating between them, you get 404 (link 1), 404 (link 2), working (link 1), working (link 2), rather than 404 (1), working (2), 404 (1), working (2).

Not really sure what next steps to take though to try to fix this.  Do we even think it is a recent problem, or is it possibly just more noticed recently because maybe there were more image attachments?  The 404s don't seem to produce any entries in the error logs in Admin Center either.

[namida]

My first suggestion would be to investigate whether other SMF-powered forums, especially those on the same version of SMF (ie: 2.0.11), also have this issue. We could also see whether any update is available and if so, whether it fixes it. If Nessy or Simon doesn't get to it first, I'll look at this when I get a chance.