xmlrpc_methods
xmlrpc_methods is a filter that filters the list of methods supported by the WordPress XML-RPC server and is related to the construction of the wp_xmlrpc_server class. It receives an array containing the current list of XML-RPC function to php function mappings as a parameter and returns the new array of mappings to be used instead. This can be used both to remove as well as add functionality to the WordPress XML-RPC interface.
Context:
File: xmlrpc.php
function wp_xmlrpc_server() {
$this->methods = array(
// Blogger API
'blogger.getUsersBlogs' => 'this:blogger_getUsersBlogs',
'blogger.getUserInfo' => 'this:blogger_getUserInfo',
'blogger.getPost' => 'this:blogger_getPost',
'blogger.getRecentPosts' => 'this:blogger_getRecentPosts',
'blogger.getTemplate' => 'this:blogger_getTemplate',
'blogger.setTemplate' => 'this:blogger_setTemplate',
'blogger.newPost' => 'this:blogger_newPost',
'blogger.editPost' => 'this:blogger_editPost',
'blogger.deletePost' => 'this:blogger_deletePost',
// MetaWeblog API (with MT extensions to structs)
'metaWeblog.newPost' => 'this:mw_newPost',
'metaWeblog.editPost' => 'this:mw_editPost',
'metaWeblog.getPost' => 'this:mw_getPost',
'metaWeblog.getRecentPosts' => 'this:mw_getRecentPosts',
'metaWeblog.getCategories' => 'this:mw_getCategories',
'metaWeblog.newMediaObject' => 'this:mw_newMediaObject',
// MetaWeblog API aliases for Blogger API
// see http://www.xmlrpc.com/stories/storyReader$2460
'metaWeblog.deletePost' => 'this:blogger_deletePost',
'metaWeblog.getTemplate' => 'this:blogger_getTemplate',
'metaWeblog.setTemplate' => 'this:blogger_setTemplate',
'metaWeblog.getUsersBlogs' => 'this:blogger_getUsersBlogs',
// MovableType API
'mt.getCategoryList' => 'this:mt_getCategoryList',
'mt.getRecentPostTitles' => 'this:mt_getRecentPostTitles',
'mt.getPostCategories' => 'this:mt_getPostCategories',
'mt.setPostCategories' => 'this:mt_setPostCategories',
'mt.supportedMethods' => 'this:mt_supportedMethods',
'mt.supportedTextFilters' => 'this:mt_supportedTextFilters',
'mt.getTrackbackPings' => 'this:mt_getTrackbackPings',
'mt.publishPost' => 'this:mt_publishPost',
// PingBack
'pingback.ping' => 'this:pingback_ping',
'pingback.extensions.getPingbacks' => 'this:pingback_extensions_getPingbacks',
'demo.sayHello' => 'this:sayHello',
'demo.addTwoNumbers' => 'this:addTwoNumbers'
);
$this->methods = apply_filters('xmlrpc_methods', $this->methods);
$this->IXR_Server($this->methods);
...
This hook is a filter which means that information is passed through it, and then used by WordPress. Your function needs to accept that information, and return it. Using add_filter('xmlrpc_methods', 'your_function'); helps you to remember this distinction. When you are passing an ID, it is assumed that you will return the ID as it was given to you. With filters that pass strings or arrays, you may manipulate the information before passing it along.