public function getContentType() {
        $contentType = $this->getHeaderValue('Content-Type');

        if ($contentType) {
            $headers     = explode(',', $contentType, 2);
            $contentType = \array_shift($headers);

            $values      = explode(';', $contentType, 2);
            $contentType = trim(\array_shift($values));
        }
        return $contentType;
    }