Web feed is a data format used for providing users with frequently updated content. In this article, we describe how to use Zend_Feed, an excellent component from Zend Framework to generate Web feed for an Yii application. This article can also serve as a general guide on how to use other components in Zend Framework.

To begin with, we download Zend Framework and extract it to the directory protected/vendors/Zend. Verify the file protected/vendors/Zend/Feed.php exists.

Then, in SiteController (or another controller if you like) create a feed action as follows,

Yii::import('application.vendors.*');
require_once('Zend/Feed.php');

public function actionFeed()
{
	// retrieve the latest 20 posts
	$posts=Post::model()->findAll(array(
		'order'=>'createTime DESC',
		'limit'=>20,
	));
	// convert to the format needed by Zend_Feed
	$entries=array();
	foreach($posts as $post)
	{
		$entries[]=array(
			'title'=>$post->title,
			'link'=>$this->createUrl('post/show',array('id'=>$post->id)),
			'description'=>$post->content,
			'lastUpdate'=>$post->createTime,
		);
	}
	// generate and render RSS feed
	$feed=Zend_Feed::importArray(array(
		'title'   => 'My Post Feed',
		'link'    => $this->createUrl(''),
		'charset' => 'UTF-8',
		'entries' => $entries,		
	), 'rss');
	$feed->send();	
}

To this end, the feed is done and we can access it via the following URL:

http://www.example.com/index.php?r=site/feed

We can insert this link to the head section of a page using the following code:

Yii::app()->clientScript->registerLinkTag(
	'alternate',
	'application/rss+xml',
	$this->createUrl('site/feed'));

We can also use [CHtml::linkTag()] to directly insert the link tag at the current place in a page. The different between these approaches is that the former code can be written anywhere while the latter can only appear in the head section of a view (or layout).

The Zend_Feed component has many other features. If you are interested, please refer to its documentation.