How do i specify a url to which to redirect the user after he logs out from facebook?

Question

I need to specify a url that i will use after the user has logged out from facebook because i need to do some extra-cleaning and he is correctly logged out from our app.

For this i need a url that when invoked will call a function i define, but i don't know how i should do this, what action i should use. In Drupal i could define a "callback menu" which is exactly what i'm looking for, i don't know how to do this in wordpress.

EDIT - to clarify more, the user is connected to my plugin with facebook connect. The standard

$logout_url = $facebook->getLogoutUrl();

isn't enough because when the user comes back from facebook i have to clear the session and invalidate the token and so i nee do specify a url

$logout_url = $facebook->getLogoutUrl('edit.php?post_type=my_custom&page=logout-from-fb');

i just need that when the user comes back from facebook automatically and the page edit.php?post_type=my_custom&page=logout-from-fb a function i want is called and it will handle everything.

Answer 1

A Web site that I recently worked on for a client involved tying WordPress together with another CMS including tight login integration. Because of clashes with internal functions, I could not call the WordPress logout function directly from the CMS. Intead, I created a special logout page in the WordPress root which I redirected to from the CMS. Following is the code for that page (logout.php):

<?php

require './wp-load.php';

$current_user = wp_get_current_user();

if ($current_user->ID != 0)
    wp_logout();

wp_redirect('/');

exit;

You'll need to somehow secure this, of course. I did so by checking the referrer to make sure the request was coming from the CMS but this might not always be reliable.