protected function setHeaderNoCache($contentType = 'application/json')
    {
        header("Content-Type: " . $contentType . "; charset=utf-8");
        header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
        header("Cache-Control: no-store, no-cache, must-revalidate");
        header("Cache-Control: post-check=0, pre-check=0", false);
        header("Pragma: no-cache");
    }