XF 1.5 Failed to load resource: net::ERR_EMPTY_RESPONSE for css.php

[Stuart Wright]

Hi folks,
we've started intermittently getting these errors on seemingly random pages. Refreshing some times fixes it, others not.

Failed to load resource: net::ERR_EMPTY_RESPONSE
https://www.avforums.com/css.php?cs...default,wmt_ytie&style=2&dir=LTR&d=1488472214

Is this a server issue?

 

[Mike]

An empty response like that is almost certainly indicative of a PHP crash. Unfortunately, they're very difficult to debug, especially if they're intermittent.

 

[Stuart Wright]

Thanks, Mike. If when it happens I were to systematically disable the various addons being included, would that be a way to identify if one of them is problematic?

 

[Mike]

Sort of. If you disabled add-ons and sat there refreshing that URL, if it's consistent, it would crash regardless. This probably isn't directly affected by add-ons beyond an add-on triggering the situation that caused the issue.

If I had to guess, it's probably more related to CSS minification, if you have that option enabled in XF. There could be a regex triggering the issue within that. If it's not consistent though (with a given URL), then that makes it super difficult to debug; it might just be something in the server environment.

 

[Stuart Wright]

Mike is there any way we can find out if there is a problem when minifying the css?

 

[Mike]

Without a consistent reproduction case, you likely need to disable the option in the control panel and see if that makes any differences.

 

[Stuart Wright]

Without a consistent reproduction case, you likely need to disable the option in the control panel and see if that makes any differences.

Early signs are that it's fixed. Is there any way the unminified css can be grabbed and analysed to find any potential issues?

 

[Mike]

Realistically, only if there's a consistent reproduction case. Doing any sort of debugging of a crash like this is potentially laborious and difficult. It would be easier with a core dump, though that may be hard to obtain (https://bugs.php.net/bugs-generating-backtrace.php, https://ma.ttias.be/generate-php-core-dumps-segfaults-php-fpm/ - there are varying methods by configuration).