public function sitemapAction(Request $request)
    {
        $urls = $this->get('zicht_url.sitemap_provider')->all($this->get('security.authorization_checker'));

        return new Response(
            $this->renderView('ZichtUrlBundle:Sitemap:sitemap.xml.twig', ['urls' => $urls]),
            200,
            [
                'content-type' => 'text/xml'
            ]
        );
    }