<?php
  
  /**
   * This is the base class for any authentication object.
   *
   * @package Sabre
   * @subpackage DAV
   * @copyright Copyright (C) 2007-2013 Rooftop Solutions. All rights reserved.
   * @author Evert Pot (http://www.rooftopsolutions.nl/) 
   * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
   */
  interface Sabre_DAV_Auth_IBackend {
  
      /**
       * Authenticates the user based on the current request.
       *
       * If authentication is successful, true must be returned.
       * If authentication fails, an exception must be thrown.
       *
       * @param Sabre_DAV_Server $server
       * @param string $realm
       * @return bool
       */
      function authenticate(Sabre_DAV_Server $server,$realm);
  
      /**
       * Returns information about the currently logged in username.
       *
       * If nobody is currently logged in, this method should return null.
       *
       * @return string|null
       */
      function getCurrentUser();
  
  }