One of the last library I didn’t documented in my earlier post was php-cloudfiles. You need to have at least the version 1.7.6 released to have support to different auth_server and when you have that you can do it like this to get access to cloud files via the library :

<?php
require_once("cloudfiles.php");

# Allow override by environment variable
$USER = "MY_API_USERNAME";
$API_KEY = "MY_API_KEY";

$auth = new CF_Authentication($USER, $API_KEY, NULL, UK_AUTHURL);
$auth->authenticate();
?>