Page Contents

Rss

class Cake\View\Helper\RssHelper(View $view, array $config = [])

The RssHelper makes generating XML for RSS feeds easy.

Deprecated since version 3.5.0: RssHelper is deprecated as of 3.5.0, and will be removed in 4.0.0

Creating an RSS Feed with the RssHelper

This example assumes you have a Articles Controller, Articles Table and an Article Entity already created and want to make an alternative view for RSS.

Creating an XML/RSS version of your Articles index action is a snap with CakePHP. After a few simple steps you can simply append the desired extension .rss to articles making your URL articles.rss. This will work with the index action included as well so articles/index would become articles/index.rss Before we jump too far ahead trying to get our webservice up and running we need to do a few things. First extensions parsing needs to be activated, this is done in config/routes.php:

Router::extensions('rss');

In the call above we’ve activated the .rss extension. When using Cake\Routing\Router::extensions() you can pass a string or an array of extensions as first argument. This will activate each extension/content-type for use in your application. Now when the address articles.rss is requested you will get an XML version of your articles index action. However, first we need to edit the controller to add in the rss-specific code.

Controller Code

It is a good idea to add RequestHandler to your ArticlesController’s initialize() method. This will allow a lot of automagic to occur:

public function initialize()
{
    parent::initialize();
    $this->loadComponent('RequestHandler');
}

Before we can make an RSS version of our articles index action we need to get a few things in order. It may be tempting to put the channel metadata in the controller action and pass it to your view using the Cake\Controller\Controller::set() method but this is inappropriate. That information can also go in the view. That will come later though, for now if you have a different set of logic for the data used to make the RSS feed and the data for the HTML view you can use the Cake\Controller\Component\RequestHandler::isRss() method, otherwise your controller can stay the same:

// Modify the Articles Controller action that corresponds to
// the action which deliver the rss feed, which is the
// Index action in our example.

public function index()
{
    if ($this->RequestHandler->isRss() ) {
        $articles = $this->Articles
            ->find()
            ->limit(20)
            ->order(['created' => 'desc']);
        $this->set(compact('articles'));
    } else {
        // this is not an Rss request, so deliver
        // data used by website's interface.
        $this->paginate = [
            'order' => ['created' => 'desc'],
            'limit' => 10
        ];
        $this->set('articles', $this->paginate($this->Articles));
        $this->set('_serialize', ['articles']);
    }
}

With all the View variables set we need to create an rss layout.

Layout

An Rss layout is very simple, put the following contents in src/Template/Layout/rss/default.ctp:

if (!isset($documentData)) {
    $documentData = [];
}
if (!isset($channelData)) {
    $channelData = [];
}
if (!isset($channelData['title'])) {
    $channelData['title'] = $this->fetch('title');
}
$channel = $this->Rss->channel([], $channelData, $this->fetch('content'));
echo $this->Rss->document($documentData, $channel);

It doesn’t look like much but thanks to the power in the RssHelper it’s doing a lot of lifting for us. We haven’t set $documentData or $channelData in the controller, however in CakePHP your views can pass variables back to the layout. Which is where our $channelData array will come from setting all of the meta data for our feed.

Next up is view file for my articles index action. Much like the layout file we created, we need to create a src/Template/Articles/rss/ directory and create a new index.ctp inside that folder. The contents of the file are below.

View

Our view, located at src/Template/Articles/rss/index.ctp, begins by setting the $documentData and $channelData variables for the layout, these contain all the metadata for our RSS feed. This is done by using the Cake\View\View::set() method which is analogous to the Cake\Controller\Controller::set() method. Here though we are passing the channel’s metadata back to the layout:

$this->set('channelData', [
    'title' => __("Most Recent Articles"),
    'link' => $this->Url->build('/', true),
    'description' => __("Most recent articles."),
    'language' => 'en-us'
]);

The second part of the view generates the elements for the actual records of the feed. This is accomplished by looping through the data that has been passed to the view ($items) and using the RssHelper::item() method. The other method you can use, RssHelper::items() which takes a callback and an array of items for the feed. The callback method is usually called transformRss(). There is one downfall to this method, which is that you cannot use any of the other helper classes to prepare your data inside the callback method because the scope inside the method does not include anything that is not passed inside, thus not giving access to the TimeHelper or any other helper that you may need. The RssHelper::item() transforms the associative array into an element for each key value pair.

Note

You will need to modify the $link variable as appropriate to your application. You might also want to use a virtual field in your Entity.

foreach ($articles as $article) {
    $created = strtotime($article->created);

    $link = [
        'controller' => 'Articles',
        'action' => 'view',
        'year' => date('Y', $created),
        'month' => date('m', $created),
        'day' => date('d', $created),
        'slug' => $article->slug
    ];

    // Remove & escape any HTML to make sure the feed content will validate.
    $body = h(strip_tags($article->body));
    $body = $this->Text->truncate($body, 400, [
        'ending' => '...',
        'exact'  => true,
        'html'   => true,
    ]);

    echo  $this->Rss->item([], [
        'title' => $article->title,
        'link' => $link,
        'guid' => ['url' => $link, 'isPermaLink' => 'true'],
        'description' => $body,
        'pubDate' => $article->created
    ]);
}

You can see above that we can use the loop to prepare the data to be transformed into XML elements. It is important to filter out any non-plain text characters out of the description, especially if you are using a rich text editor for the body of your blog. In the code above we used strip_tags() and h() to remove/escape any XML special characters from the content, as they could cause validation errors. Once we have set up the data for the feed, we can then use the RssHelper::item() method to create the XML in RSS format. Once you have all this setup, you can test your RSS feed by going to your site /articles.rss and you will see your new feed. It is always important that you validate your RSS feed before making it live. This can be done by visiting sites that validate the XML such as Feed Validator or the w3c site at http://validator.w3.org/feed/.

Note

You may need to set the value of ‘debug’ in your core configuration to false to get a valid feed, because of the various debug information added automagically under higher debug settings that break XML syntax or feed validation rules.