Custom XML-RPC methods can't reuse functions in WordPress' XML-RPC server object

[davecpage]

When extending XML-RPC with custom methods you cannot reuse the functions of the main WordPress wp_xmlrpc_server object. The object does all it's work within the constructor function and by the time any other code could use the global variable $wp_xmlrpc_server everything has finished.

This issue was discovered during the recent WordCampUK WordHack session and meant we couldn't reuse the built-in login function of wp_xmlrpc_server to authenticate a user.

The code just needs to finish assigning the object to $wp_xmlrpc_server on line 3405 then have a separate function that calls the base IXR_Server function on line 204.

I have a patch that adds this extra step but it can be adjusted if needed.

This sounds fine. I did have a problem with seg faulting with your patch though. Seems it didn't like having a class method called serve. I've created a new patch changing this to serve_request and it stopped seg faulting.

(In [11789]) Seperate out the XML-RPC server active behaviour from object construction so that plugins can use the utility functions when extending the XML-RPC server. Fixes #10513 props davecpage.