public function getContentType()
    {
        if (isset($this->_contentType)) {
            return $this->_contentType;
        }
        if (isset($_SERVER["CONTENT_TYPE"])) {
            return $this->_contentType = $_SERVER["CONTENT_TYPE"];
        } elseif (isset($_SERVER["HTTP_CONTENT_TYPE"])) {
            //fix bug https://bugs.php.net/bug.php?id=66606
            return $this->_contentType = $_SERVER["HTTP_CONTENT_TYPE"];
        }

        return null;
    }