Nelmio\SecurityBundle\ExternalRedirect\WhitelistBasedTargetValidator::isTargetAllowed PHP Method

    public function isTargetAllowed($target)
    {
        if ($this->whitelist === null || empty($this->whitelist)) {
            return false;
        }
        return preg_match('{^' . $this->whitelist . '$}i', parse_url($target, PHP_URL_HOST)) > 0;
    }