/**
  * Default controller action for the sitemap.xml file. Renders a index
  * file containing a list of links to sub sitemaps containing the data.
  *
  * @return mixed
  */
 public function index($url)
 {
     if (GoogleSitemap::enabled()) {
         Config::inst()->update('SSViewer', 'set_source_file_comments', false);
         $this->getResponse()->addHeader('Content-Type', 'application/xml; charset="utf-8"');
         $this->getResponse()->addHeader('X-Robots-Tag', 'noindex');
         $sitemaps = GoogleSitemap::get_sitemaps();
         $this->extend('updateGoogleSitemaps', $sitemaps);
         return array('Sitemaps' => $sitemaps);
     } else {
         return new SS_HTTPResponse('Page not found', 404);
     }
 }