protected function filterAlfanumeric($field, $details, $label, $message) {
        if (!$this->filterString($field, $details, $label, $message)) {
            return false;
        }
        if (ctype_alnum($this->getValue($field))) {
            return true;
        }

        throw new \Exception($message ? $message : $this->translate("$label must be alfanumeric!"));
    }