public static function checkUrlForBlacklisting($url, array $blacklistConf)
    {
        // check for valid url
        if (empty($url)) {
            return true;
        }

        $blacklistConf = (array)$blacklistConf;
        foreach ($blacklistConf as $blacklistRegExp) {
            if (preg_match($blacklistRegExp, $url)) {
                return true;
            }
        }

        return false;
    }