silverstripe-framework/docs/en/reference/rssfeed.md
Michael Parkhill bd5abb62ff FIX: parent::init is not called first
In the controller's init function, parent::init() should be called before any other method calls.
2014-05-01 15:35:45 +12:00

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# RSS Feed
## Introduction
Generating RSS/Atom-feeds is a matter of rendering a `[api:SS_List]` through
the `[api:RSSFeed]` class.
The `[api:RSSFeed]` class doesn't limit you to generating article based feeds,
it is just as easy to create a feed of your current staff members, comments or
any other custom `[api:DataObject]` subclasses you have defined. The only
logical limitation here is that every item in the RSS-feed should be accessible
through a URL on your website, so its advisable to just create feeds from sub
classes of `[api:SiteTree]`.
If you wish to generate an RSS feed for `[api:DataObject]` instances, ensure they
define an AbsoluteLink() method.
## Usage
:::php
RSSFeed::linkToFeed($link, $title)
This line should go in your `[api:Controller]` subclass in the action you want
to include the HTML link. Not all arguments are required, see `[api:RSSFeed]` and example below. Last Modified Time is expected in seconds like time().
:::php
$feed = new RSSFeed(
$list,
$link,
$title,
$description,
$titleField,
$descriptionField,
$authorField,
$lastModifiedTime,
$etag
);
Creates a new `[api:RSSFeed]` instance to be returned. The arguments notify
SilverStripe what values to include in the feed.
## Examples
### Showing latest blog posts
:::php
class Page_Controller extends ContentController {
private static $allowed_actions = array('rss');
public function init() {
parent::init();
// linkToFeed will add an appropriate HTML link tag to the website
// <head> tag to notify web browsers that an RSS feed is available
// for this page. You can include as many feeds on the page as you
// wish as long as each as a different link. For example:
// ('blog/rss', 'staff/rss').
//
// In this example $this->Link("rss") refers to the *rss* function
// we define below.
RSSFeed::linkToFeed($this->Link("rss"), "RSS feed of this blog");
}
public function rss() {
// Creates a new RSS Feed list
$rss = new RSSFeed(
$list = $this->getBlogPosts(), // an SS_List containing your feed items
$link = $this->Link("rss"), // a HTTP link to this feed
$title = "My feed", // title for this feed, displayed in RSS readers
$description = "This is an example feed." // description
);
// Outputs the RSS feed to the user.
return $rss->outputToBrowser();
}
public function getBlogPosts() {
return BlogPage::get()->limit(10);
}
}
### Showing the 10 most recently updated pages
You can use `[api:RSSFeed]` to easily create a feed showing your latest Page
updates. Update mysite/code/Page.php to something like this:
:::php
<?php
class Page extends SiteTree {}
class Page_Controller extends ContentController {
private static $allowed_actions = array('rss');
public function init() {
parent::init();
RSSFeed::linkToFeed($this->Link() . "rss", "10 Most Recently Updated Pages");
}
public function rss() {
$rss = new RSSFeed($this->LatestUpdates(), $this->Link(), "10 Most Recently Updated Pages", "Shows a list of the 10 most recently updated pages.");
return $rss->outputToBrowser();
}
public function LatestUpdates() {
return Page::get()->sort("LastEdited", "DESC")->limit(10);
}
}
### Rendering DataObjects in a RSSFeed
DataObjects can be rendered in the feed as well, however, since they aren't explicitly
`[api:SiteTree]` subclasses we need to include a function `AbsoluteLink` to allow the
RSS feed to link through to the item.
If the items are all displayed on a single page you may simply hard code the link to
point to a particular page.
Take an example, we want to create an RSS feed of all the Students, a DataObject we
defined in the [fifth tutorial](/tutorials/5-dataobject-relationship-management).
:::php
<?php
class Student extends DataObject {
public function AbsoluteLink() {
// see tutorial 5, students are assigned a project, so the 'link'
// to view the student is based on their projects link.
return $this->Project()->AbsoluteLink();
}
}
Then update the Page_Controller class in mysite/code/Page.php to include an RSSFeed
for all the students as we've seen before.
:::php
class Page_Controller extends ContentController {
private static $allowed_actions = array('students');
public function init() {
parent::init();
RSSFeed::linkToFeed($this->Link("students"), "Students feed");
}
public function students() {
$rss = new RSSFeed(
$list = $this->getStudents(),
$link = $this->Link("students"),
$title = "Students feed"
);
return $rss->outputToBrowser();
}
public function getStudents() {
return Student::get()->sort("Created", "DESC")->limit(10);
}
}
### Customizing the RSS Feed template
The default template used is framework/templates/RSSFeed.ss and includes
displaying titles and links to the content. If you have a particular need
for customizing the XML produced (say for additional meta data) use `setTemplate`.
Taking that last example, we would rewrite the students function to include a
unique template (write your own XML in themes/yourtheme/templates/Students.ss)
:::php
public function students() {
$rss = new RSSFeed(
$list = $this->getStudents(),
$link = $this->Link("students"),
$title = "Students feed"
);
$rss->setTemplate('Students');
return $rss->outputToBrowser();
}
## External Sources
`[api:RSSFeed]` only creates feeds from your own data. We've included the [SimplePie](http://simplepie.org) RSS-parser for
accessing feeds from external sources.
## Related
* [blog module](http://silverstripe.org/blog-module)
## API Documentation
* `[api:RSSFeed]`