sending xml and headers via curl - php

Question

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

Answer 1

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.