public function strategy()
    {
        //when session support is enabled add that to file name
        $session_str = SessionHandler::process();

        $uri = empty($_SERVER['REQUEST_URI']) ? 'uri' : $_SERVER['REQUEST_URI'];
        $query = empty($_SERVER['QUERY_STRING']) ? 'query' : $_SERVER['QUERY_STRING'];

        return md5($uri . $_SERVER['SCRIPT_NAME'] . $query . $session_str);
    }