protected function _createFile()
        {
            do {
                $this->_filename = $this->getPath() .  mt_rand() . '.html';
            } while(File::exists($this->_filename));

            /**
             * create an empty file
             */
            File::put($this->_filename, $this->getHtml());
            chmod($this->_filename, 0777);

            return $this->_filename;
        }