PHP: How to forward on $_FILES using cURL

I'm trying to use cURL to forward on a http request from a form in a web application I'm developing. Essentially I need to submit the same form 开发者_开发百科twice on different servers, for the second server I'm adding some security measures to the post data.

I can receive $_POST information on the second form perfectly fine, however I'm having major troubles with my $_FILES - I've tried separating the two so there's a separate request for post and files data but still no luck.

Is this possible?

<?php
$filename = '/foo/bar';
$postargs = array(
   'foo' =>'bar', //normal postfield
   'fileentry' => '@'.$filename //be sure to give it as an absolute path!, $_FILES['fileentry']['tmp_name'] usually has this
 );

$ch = curl_init();
//other stuff with curl
curl_setopt($ch,CURL_POSTFIELDS, $postargs);//give as array for proper encoding.
curl_exec();
?>

You can:

• force PHP not to process the files (see this question for details);
• use curl to submit file_get_contents('php://input') as raw post data (see this question for details). You will also have to forward some HTTP headers with CURLOPT_HTTPHEADER, namely Content-Length and Content-type.

This avoids hitting the filesystem.