PHP Curl POST Problem Causing PHP to use 100% CPU

Question

I'm trying to upload data with POST to my webserver but sometimes cURL just stalls and causes PHP to use 100% CPU indefinitely.

I'm using the code below.

$curl = curl_init();
curl_setopt($curl, CURLOPT_URL, $URL);
curl_setopt($curl, CURLOPT_POST, true);
curl_setopt($curl, CURLOPT_CONNECTTIMEOUT, 5);
curl_setopt($curl, CURLOPT_POSTFIELDS, $postdata);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
curl_setopt ($curl, CURLOPT_USERAGENT, 'Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)');
curl_setopt($curl, CURLOPT_HEADER, true);
$page = curl_exec($curl);
curl_close($curl);

Any insight to what is causing or how to track this issue would be great.

Answer 1

Upgrade to the newest version of PHP, PHP 5.3.1.

If the problem still persists, and your server is running Windows, upgrade it to anything else, particularily a form of *NIX: a GNU/Linux distribution, a form of BSD, SunOS, etc...

If the problem persists even then, or you think Windows is a good OS for servers [1], the instructions to track the problem and send a bug report are over here: http://bugs.php.net/how-to-report.php

[1] Microsoft itself has to restart each machine behind microsoft.com every month.

Answer 2

Can you determine if it's related to a specific file? Perhaps there's something related to encoding, or upload length?

My first thought would be to at least determine if a specific file/set of files are causing the problem; write out the filenames (and perhaps content) and types before the upload, and the filename after it completes. That way you'll know exactly which files are causing the problem, and you can move on from there.

Answer 3

If it really is the actual curl "call" that hangs and performs 100% CPU, then that is a curl bug and you should probably consider upgrading your libcurl.

Answer 4

Perhaps the issue is with what you're specifying as the post data. Could you do a var_dump($postdata) right before your call to cURL and post the output here? cURL could be getting hung up on a typecasting/serialization issue, or your post data is simply invalid (and hopefully we can correct it!).