Source for file logout.act.php

<?php
/**
 * @since 7/21/05
 * @package polyphony.authentication
 * 
 * @copyright Copyright &copy; 2005, Middlebury College
 * @license http://www.gnu.org/copyleft/gpl.html GNU General Public License (GPL)
 *
 * @version $Id: logout.act.php,v 1.10 2007/09/19 14:04:53 adamfranco Exp $
 */ 
 
require_once(POLYPHONY."/main/library/AbstractActions/Action.class.php");
 
/**
 * Change the language to the one specified by the user
 * 
 * @since 7/21/05
 * @package polyphony.language
 * 
 * @copyright Copyright &copy; 2005, Middlebury College
 * @license http://www.gnu.org/copyleft/gpl.html GNU General Public License (GPL)
 *
 * @version $Id: logout.act.php,v 1.10 2007/09/19 14:04:53 adamfranco Exp $
 */
class logoutAction
    extends Action
{
        
    /**
     * Check Authorizations
     * 
     * @return boolean 
     * @access public
     * @since 4/26/05
     */
    function isAuthorizedToExecute () {
        return TRUE;
    }
    
    /**
     * Execute this action.
     * 
     * @param object Harmoni $harmoni 
     * @return mixed 
     * @access public
     * @since 4/25/05
     */
    function execute ( $harmoni ) { 
        $authN = Services::getService("AuthN");
        
        // dethenticate. :-)
        $authN->destroyAuthentication();
        
        // Send us back to where we were
        $harmoni->history->goBack("polyphony/login");
        
        $null = null;
        return $null;
    }
}