public function updateCacheDetails()
    {
        $date         = $this->http->getDate(time());
        $maxAge       = $this->http->getMaxAge($this->defaultMaxAge);
        $lastModified = $this->http->getLastModified();

        $this->cache['Date']    = gmdate("D, d M Y H:i:s T", $date);
        $this->cache['Max-Age'] = $maxAge;

        if ($lastModified) {
            $this->cache['Last-Modified'] = gmdate("D, d M Y H:i:s T", $lastModified);
        }

        file_put_contents($this->fileJson, json_encode($this->cache));
        return $this->fileName;
    }