XRPC_Server is a simple as possible XML-RPC server component I wrote for a project a year or two ago, and is a good alternative if you want to try to stay away from large frameworks or complex components. The component is license under the MIT License, so you’re pretty much free to do whatever you want with it. All patches are welcome! The server requires PHP5 and reflection enabled.
Usage is as simple as requiring the php-file into your "gateway" page (the URL you’ll be calling from your XML-RPC clients), and then creating the server object with the functions you want to expose as the argument to the constructor:
$server = new XRPC_Server(array( 'multiply' => 'test_xmlrpc_multiply', 'dateTest' => 'test_xmlrpc_date_test', 'assoc' => 'test_xmlrpc_assoc', 'array' => 'test_xmlrpc_array', ));
A simple file illustrating the usage is also included, XRPC_Server_Test.php.
You can see the source code of the server at XRPC_Server.phps .
The class can be downloaded from this site: XRPC_Server.tar.bz2