RegistrationModel::validateUserName PHP Метод

    public static function validateUserName($user_name)
    {
        if (empty($user_name)) {
            Session::add('feedback_negative', Text::get('FEEDBACK_USERNAME_FIELD_EMPTY'));
            return false;
        }
        // if username is too short (2), too long (64) or does not fit the pattern (aZ09)
        if (!preg_match('/^[a-zA-Z0-9]{2,64}$/', $user_name)) {
            Session::add('feedback_negative', Text::get('FEEDBACK_USERNAME_DOES_NOT_FIT_PATTERN'));
            return false;
        }
        return true;
    }