cURL 403 Error Returning

The other day at work we ran into an issue where the server would return a 403 error page when retrieving page information from a cURL call. After searching around the web for a while thinking that we had a server permission issue on our hands it ended up just being a PHP problem.

In order to make a cURL request from your own server you must first make sure that the session has been destroyed prior to and cURL commands. This is because your server cannot have two pages that can access sessions up at the same time and the primary file that you are working from is going to lock the secondary file that you are trying to bring in.

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<?php
session_start();
 
//authentication code.
 
//destroy session first.
session_destroy();
 
//cURL code.
$ch_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, $fields_string);
$response = curl_exec($ch)
curl_close($ch);
 
//now we can start the session again
session_start();
 
//do some other stuff...

My only guess as to why PHP does this is to protect itself from breaking sessions with multiple page access which is a pretty good security issue to have in place. Better error reporting would have been nice though.