[wp-hackers] overriding pluggable.php functions

[Will Norris]

I've been toying around with this thought for a little while, and  
would like hear what others think.  Right now I'm working on an OAuth  
plugin for WordPress.  If we can get it all done in time, it may go  
into WP 2.8, but for the time being I'm just writing it as a plugin.   
One of the things I'm doing is to override wp_authenticate for XML-RPC  
requests so that I can do OAuth authentication rather than standard  
username and password.  This much is really simple:

if (XMLRPC_REQUEST && !function_exists('wp_authenticate')) {
     function wp_authenticate($username, $password) { /* My custom  
function */ }
}

My problem is that if the current request is not using OAuth, then I'd  
like to fall back to the standard username/password logic found in  
pluggable.php.  Unfortunately, because pluggable.php works by  
completely replacing the functions, I can't call that version of  
wp_authenticate.  The only way I could fall back to that logic is to  
completely copy and paste it all into my custom wp_authenticate  
function.  This is of course bad practice, and not future-proof.  So  
I've been thinking about how it would work if pluggable.php were  
instead made up of functions like:

if (!function_exists('wp_authenticate')) {
     function wp_authenticate($username, $password) {
         return _wp_authenticate($username, $password) {
     }
}

function _wp_authenticate($username, $password) {
     /* all the normal authentication logic */
}

So basically, the functions which can be replaced by plugins don't  
actually include any logic whatsoever, they simply call "private"  
counterparts.  This way, I can override wp_authenticate, but can still  
fall back by calling _wp_authenticate myself.  Just to be clear, this  
has nothing to do with OAuth directly... that just happens to be the  
thing I'm working on right now.  I've actually run into this quite  
regularly for a number of different functions in pluggable.php.  If  
this has already been discussed, just point me to that thread so I can  
get caught up.

Thoughts?

-will