504 Gateway Time-out when calling curl_exec() in PHP with SSL peer verification (CURLOPT_SSL_VERIFYPEER) off

Ben Johnson ben at indietorrent.org
Fri Aug 23 20:28:24 UTC 2013

On 8/23/2013 3:23 PM, Maxim Dounin wrote:
> Hello!
> On Fri, Aug 23, 2013 at 02:41:43PM -0400, Ben Johnson wrote:
>> On 8/23/2013 2:05 PM, Maxim Dounin wrote:
>>> Hello!
>>> On Fri, Aug 23, 2013 at 12:46:44PM -0400, Ben Johnson wrote:
>>>> Hello,
>>>> I'm seeing a strange problem with nginx (1.5.2 on Windows) and PHP
>>>> (5.4.8 on Windows).
>>>> Whenever I make a cURL request with PHP's curl_exec() function to a
>>>> secure URL (https protocol), and I disable peer verification, like this
>>>> curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);
>>>> nginx responds with a "504 Gateway Time-out".
>>>> If I set CURLOPT_SSL_VERIFYPEER to TRUE, nginx responds with a "200 OK",
>>>> although curl_exec() returns false, which is expected due to the
>>>> verification failure (I'm using a self-signed certificate in nginx).
>>>> I have tried executing the same script under Apache and it functions as
>>>> expected with peer verification disabled.
>>> What URL is requested by your script?  Symptoms described suggest 
>>> you are requesting some php script from the same server, and 504 
>>> is likely due to only one php backend process.
>> Thank you for the quick reply, Maxim! I appreciate it.
>> You are exactly right; my script requests another URL on the same server
>> (which happens to be localhost in this case).
>> Just so I understand the problem, are you saying that the script that
>> contains the cURL call (via PHP's curl_exec() function) essentially
>> ties-up the only available PHP backend process, which causes curl_exec()
>> to time-out when it requests another URL on the same server?
>> Is there a solution to this problem?
>> My setup is essentially the same as what is described at
>> http://wiki.nginx.org/PHPFastCGIOnWindows .
> If you are using php-cgi, configuring PHP_FCGI_CHILDREN 
> environment variable before starting php-cgi should help.

Thank you for the suggestion, Maxim.

I set PHP_FCGI_CHILDREN to 4, 20, etc., but it doesn't seem to make any
difference. Here is the Windows batch script that I'm using to start
php-cgi.exe (please excuse the wrapping):

ECHO Starting PHP FastCGI...
SET PATH="C:\Program Files\php;%PATH%"
"C:\Program Files\php\php-cgi.exe" -b -c "C:\Program

Any other ideas?

Thanks again,


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