public function generate($url)
    {
        $time = time();
        $query = parse_url($url, PHP_URL_QUERY);
        parse_str($query, $query);

        $query = $this->filterKeys($query, $this->params);
        $query['timestamp'] = $time;

        $signature = $this->generateToken($query);

        return $url . '&timestamp=' . $time . '&signature=' . $signature;
    }