Extending the REST API

The eZ Publish 5 REST API comes with a framework that makes it quite easy to extend the API for your own needs.

Requirements

As of version 2013.7, REST routes are required to use the eZ Publish 5 REST API prefix, /api/ezp/v2. You can create new resources below this prefix.

To do so, you will/may need to create

• a Controller that will handle your route actions
• a Route, in your bundle's routing file
• a Controller action
• Optionally, a ValueObjectVisitor
• Optionally, an InputParser

Controller

To create a REST controller, you need to extend the ezpublish_rest.controller.base service, as well as the eZ\Publish\Core\REST\Server\Controller class.

Let's create a very simple controller, that has a sayHello() method, that takes a name as an argument.

Route

As said earlier, your REST routes are required to use the REST URI prefix. To do so, the easiest way is to import your routing file using this prefix.

Using a distinct file for REST routes allows you to use the prefix for all this file's routes without affecting other routes from your bundle.

Next, you need to create the REST route. We need to define the route's controller as a service since our controller was defined as such.

Controller action

Unlike standard Symfony 2 controllers, the REST ones don't return an HttpFoundation\Response object, but a ValueObject. This object will during the kernel run be converted, using a ValueObjectVisitor, to a proper Symfony 2 response. One benefit is that when multiple controllers return the same object, such as a Content or a Location, the visitor will be re-used.

Let's say that our Controller will return a My\Bundle\RestBundle\Rest\Values\Hello

We will return an instance of this class from our sayHello() controller method.

And that's it. Converting this object requires that we create a ValueObjectVisitor.

ValueObjectVisitor

A ValueObjectVisitor will take a Value returned by a REST controller, whatever the class, and will transform it into data that can be converted, either to json or XML. Those visitors are registered as services, and tagged with ezpublish_rest.output.value_object_visitor. The tag attribute says which class this Visitor applies to.

Let's create the service for our ValueObjectVisitor first.

Let's create our visitor next. It must extend the eZ\Publish\Core\REST\Common\Output\ValueObjectVisitor abstract class, and implement the visit() method.
It will receive as arguments: