public function assembleRoute($message, $extension = null, $size = null, $padding = null)
    {
        $params = array('message' => $message);
        if (isset($extension)) {
            $params['extension'] = $extension;
            if (isset($size)) {
                $params['size'] = $size;
                if (isset($padding)) {
                    $params['padding'] = $padding;
                }
            }
        }

        $this->routeOptions['name'] = 'acelaya-qrcode';
        return $this->router->assemble($params, $this->routeOptions);
    }