Using mod_rewrite And Zend Framework To Display Dynamic sitemap.xml

Whilst creating a site the other day I thought about how I would manage the sitemap.xml file. This file is basically a XML file containing a list of URLs. Most major search engines understand (and look for) this file, so having it present on a site is a definite must.

I have been down the route before of having a sitemap.xml file created by the application every time a new record or something was added, but as this was a high traffic, multi-user site this approach just had to many problems. The main problem (aside from the potential performance hit) was that I would have to spend hours tying the calls to the sitemap.xml creation file into my application.

I then hit upon the idea of using a RewriteRule that would mask a controller as the sitemap.xml file. This would mean that the sitemap.xml controls could be kept away from all other parts of the application (so I could use the same template again), but I could also use Zend_Cache to cache the sitemap.xml file daily and therefore save on processing time.

First I needed to create a RewriteRule that would redirect a call to sitemap.xml to the Sitemap controller.

RewriteRule ^(.*)sitemap.xml$ /sitemap/index [L]

Next I created the Sitemap controller and made sure that the index action did not show the layout. The URLs are passed as an array to the view.

class SitemapController extends Zend_Controller_Action


{


    public function indexAction()


    {


        $this->_helper->layout()->disableLayout();


        $urls = array(array('loc'=>'http://www.hashbangcode.com/', 'lastmod'=>'2009-04-02T11:34:48+00:00', 'changefreq'=>'daily', 'priority'=>'1.0'));


 


        $this->view->urls = $urls;


    }


}

In order for the Sitemap controller to display anything it needs to have a view to render. This creates the basic outline of the file and uses the partialLoop() function to print out the array of URLs.

partialLoop('sitemap/_urlItem.phtml',$this->urls); ?>

Here is the file _urlItem.phtml, which gets rendered for every item in the $this->urls array.

<url><loc><?php echo $this-?>loc; ?></loc><lastmod><?php echo $this-?>lastmod; ?></lastmod><changefreq><?php echo $this-?>changefreq; ?></changefreq><priority><?php echo $this-?>priority; ?></priority></url>

I assumed that everything would be working nicely now, but when I went to a browser and tried to find sitemap.xml I was presented with a message that said sitemap.xml was an invalid controller.

Just to test I added a redirect to the end of the RewriteRule to make sure that the rule worked.

RewriteRule ^(.*)sitemap.xml$ /sitemap/index [R=301, L]

This redirected to the correct place, so it must have been Zend Framework that was causing the error to occur. After a bit of thinking I realised that I could create a route that would reroute the call to the missing sitemap.xml controller to the existing Sitemap controller. Here is the rule I created, just add this to your bootstrap file.

$router = $frontController->getRouter();


$router->addRoute(


    'manageSitemap',


    new Zend_Controller_Router_Route('sitemap.xml', array('controller'=>'sitemap','action'=>'index'))


);

Navigating to sitemap.xml now shows me the output of the Sitemap controller.