protected static function prepareRequest($httpHeaders = array(), $dataArray = array())
    {

        self::$postDataJSON = json_encode($dataArray);

        self::$httpHeaders = $httpHeaders;

        if (!empty($dataArray)) {
            self::$httpHeaders['Content-type'] = 'application/json';
            self::$httpHeaders['Content-Length'] = strlen(self::$postDataJSON);
        }
    }