sending xml and headers via curl

wondering how I can set all this data in a curl session, via php:

POST /feeds/api/users/default/uploads HTTP/1.1
Host: uploads.gdata.youtube.com
Authorization: AuthSub token="DXAA...sdb8"
GData-Version: 2
X-GData-Key: key=adf15ee97731bca89da876c...a8dc
Slug: video-test.mp4
Content-Type: multipart/related; boundary="f93dcbA3"
Content-Length: 1941255
Connection: close

--f93dcbA3
Content-Type: application/atom+xml; charset=UTF-8

<?xml version="1.0"?>
<entry xmlns="http://www.w3.org/2005/Atom"
  xmlns:media="http://search.yahoo.com/mrss/"
  xmlns:yt="http://gdata.youtube.com/schemas/2007">
  <media:group>
    <media:title type="plain">Bad Wedding Toast</media:title>
    <media:description type="plain">
      I gave a bad toast at my friend's wedding.
    </media:description>
    <media:category
      scheme="http://gdata.youtube.com/schemas/2007/categories.cat">People
    </media:category>
    <media:keywords>toast, wedding</media:keywords>
  </media:group>
</entry>
--f93dcbA3
Content-Type: video/mp4
Content-Transfer-Encoding: binary

<Binary File Data>
--f93dcbA3--

I don't understand why have some headers, then the --f93dcbA3 more headers (what's the boundary?), some xml (why here ?), more headers and the content of a file.

I know how to make the request without the xml part and the 'boundary'.

Any help will be appreciated :D

The boundary is required because the form enctype is multipart/form-data, rather in this case multipart/related. The boundary is a unique string that cannot appear anywhere else in the request, and it is used to separate each element from the form, whether it is the value of a text input, or a file upload. Each boundary has its own content-type.

Curl cannot do multipart/related for you, so you will need to use a workaround, see this message from the curl mailing list for suggestions. Basically, you will have to construct most of the message yourself.

Note, the last boundary has an additional -- at the end.

This code should hopefully help get you started:

<?php

$url       = 'http://uploads.gdata.youtube.com/feeds/api/users/default/uploads';
$authToken = 'DXAA...sdb8'; // token you got from google auth
$boundary  = uniqid();      // generate uniqe boundary
$headers   = array("Content-Type: multipart/related; boundary=\"$boundary\"",
                   "Authorization: AuthSub token=\"$authToken\"",
                   'GData-Version: 2',
                   'X-GData-Key: key=adf15....a8dc',
                   'Slug: video-test.mp4');

$postData  = "--$boundary\r\n"
            ."Content-Type: application/atom+xml; charset=UTF-8\r\n\r\n"
            .$xmlString . "\r\n"  // this is the xml atom data
            ."--$boundary\r\n"
            ."Content-Type: video/mp4\r\n"
            ."Content-Transfer-Encoding: binary\r\n\r\n"
            .$videoData . "\r\n"  // this is the content of the mp4
            ."--$boundary--";


$ch  = curl_init($url);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $postData);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);

$response = curl_exec($ch);
curl_close($ch);

Hope that helps.