public function indexAction()
    {
        $response = $this->response;

        $mainPage = new \stdClass();
        $mainPage->services = $this->determineServices(
            $this->restUtils->getOptionRoutes()
        );

        $mainPage->thirdparty = $this->registerThirdPartyServices();

        $response->setContent(json_encode($mainPage));
        $response->setStatusCode(Response::HTTP_OK);
        $response->headers->set('Link', $this->prepareLinkHeader());

        // todo: make sure, that the correct content type is set.
        // todo: this should be covered by a kernel.response event listener?
        $response->headers->set('Content-Type', 'application/json');

        return $response;
    }