I recently developed a prototype for a client who insisted that the site include an RSS feed for the articles of the site. Not being one to turn down a challenge, and being aware of the Power of Cake, I assured them it could be completed with such a feature. The newsfeed would provide the latest articles to be consumed by an aggregation software or other feed reader. So in the text that follows I’ll outline what is involved to add news feed or rss feeds to a particular model of your CakePHP site.

The Problem

News feeds are everywhere and essential in todays web development.  Your sites are just as good as anyone elses, and deserve this critical feature.

The Solution

Implement a url that can be consumed by web browsers or feed readers to publicize your latest content to the world.

Implementing a Feed Generator in CakePHP

If we think about this rationally there are 3 peices;

• A controller action to retrieve the latest articles
• A view to generate the xml formatted excerpts
• A routing piece to provide an acceptable url

The RSS Feed Action

No need to over complicate things here. Imagine you have a standard Model, oh let’s say ‘Posts’.  All we need to do here is add a newsfeed action. By default the action will pull 5 posts within the last month, but the number can be overridden by passing a different number in the url (as with any action parameter).

app/controllers/posts_controller.php -snippet

<?
/**
 * Returns an array of all public posts less than one month old, orderd by date
 *
 * @return unknown
 */ 
function newsfeed($count=null) {
	if(!$count) $count=5;
	$this->Post->recursive = 0;
	$posts=$this->Post->findAll('is_public = 1 
			AND is_published = 1 
			AND Post.date_modified >= now() - INTERVAL 1 MONTH'
				,null,'Post.date_modified DESC',$count);
	if(isset($this->params['requested'])) {
                     return $posts;
             }
             $this->set('posts',$posts );
}

It would be really helpful if CakePHP provided an RSS helper. Zoot alors !  They do!

app/controllers/posts_controller.php -snippet

<?
var $helpers = array('Rss');
var $components = array ('RequestHandler');

The XML Generating View

Just like any other view, all we need to do is transform some provided data into a formatted page. This time it will be strict XML without all the html clutter.

app/views/posts/rss/newsfeed.ctp

<?
 $item['Post']['title'],
		'link' => array('controller' => 'posts', 'action' => 'view', $item['Post']['id']),
		'guid' => array('controller' => 'posts', 'action' => 'view', $item['Post']['id']),
		'description' => strip_tags($item['Post']['body']),
		'pubDate' => $item['Post']['date_added'],				
	);
}

$this->set('items', $rss->items($posts, 'rss_transform'));

$this->set('channelData', $channelData);

And of course sticking with format we should want to add an RSS layout.

app/views/layouts/rss/default.ctp

<?
header();
		$channelData = array('title' => 'Recent News | Digital Business',
		 'link' => array('controller' => 'posts', 'action' => 'index', 'ext' => 'rss'),
		 'url' => array('controller' => 'posts', 'action' => 'index', 'ext' => 'rss'),
		 'description' => 'The best Digital Business RSS Feed on the web',
		 'language' => 'en-us'
		 );
$channel = $rss->channel(array(), $channelData, $items);
echo $rss->document(array(), $channel);

The RSS compliant URL

You only need to add 2 lines to your routes configuration file for CakePHP to catch and handle the url to pint to your RSS feed. You might use feed.rss, I choice live.rss.

app/config/routes.php -snippet

<?
/**
 * ...allow rssextensions
 * and send live.rss to the rss feed
 */
	Router::connect('/live', array('controller' => 'posts', 'action' => 'newsfeed'));
    // see my posts on sitemaps to use this next line ;)	
    Router::connect('/sitemap', array('controller' => 'sitemaps', 'action' => 'index'));
	
	Router::parseExtensions('rss','xml');

Yes, you’ll notice an additional route there for dynamic sitemaps, very useful as well. Sweet! Now just visit http://example.com/live.rss, or throw that url in your favorite Feed Reader to see the results.

http://example.com/live.rss

Recent News | Digital Business http://digbiz.localhost/posts.rss

    The best Digital Business RSS Feed on the web
	en-us
     This is a Public, Published General News Article
        http://digbiz.localhost/posts/view/1
        http://digbiz.localhost/posts/view/1
        It should be visible by ALL users and guests.
        Tue, 22 Jul 2008 11:22:51 -0400 
     New Public News
        http://digbiz.localhost/posts/view/6
        http://digbiz.localhost/posts/view/6
        Lets spice this up a bit...
        Fri, 01 Aug 2008 13:00:25 -0400 
     Neil Hair Guest Essay in Democrat and Chronicle
        http://digbiz.localhost/posts/view/9
        http://digbiz.localhost/posts/view/9
         Dr. Neil Hair comments on the Virtual Workforce of the
            future.
            http://www.democratandchronicle.com/apps/pbcs.dll/article?AID=2008810050343
        Mon, 06 Oct 2008 09:03:36 -0400