protected function validateRedirectURL()
    {
        if (!filter_var($this->redirectURL, FILTER_VALIDATE_URL)) {
            // Not a full URL
            if (!preg_match('#^/[a-zA-Z0-9_/.-]*#', $this->redirectURL)) {
                // Not a valid path either
                $this->setNotReady("Invalid redirect URL entered.", null, 404);
                return;
            }
        }
    }