Extending the REST API¶
The eZ Platform REST API comes with a framework that makes it easy to extend the API for your own needs.
REST routes are required to use the eZ Platform 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(if your controller returns an object that doesn't already have a converter)
- optionally, an
To create a REST controller, you need to extend the
ezpublish_rest.controller.base service, as well as the
First create a simple controller that has a
sayHello() method which takes a name as an argument.
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As mentioned 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.
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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. Define the route's controller as a service since your controller was defined as such.
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Due to EZP-23016 - Custom REST API routes (v2) are not accessible from the legacy backend, custom REST routes must be prefixed with
ezpublish_rest_, or they won't be detected correctly.
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Unlike standard Symfony 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 response. One benefit is that when multiple controllers return the same object, such as a Content item or a Location, the visitor will be re-used.
Let's say that your controller will return a
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An instance of this class will be returned from
sayHello() controller method.
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Outputting this object in the response requires that you create 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 format. 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.
Create the service for your
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Create your visitor next. It must extend the
eZ\Publish\Core\REST\Common\Output\ValueObjectVisitor abstract class, and implement the
It will receive as arguments:
||The output visitor. Can be used to set custom response headers (
||The actual response generator. It provides you with a DOM like API.|
||The visited data. The exact object you returned from the controller|
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The easiest way to handle cache is to re-use the
CachedValue Value Object. It acts as a proxy, and adds the cache headers, depending on the configuration, for a given object and set of options.
When you want the response to be cached, return an instance of
CachedValue, with your Value Object as the argument. You can also pass a Location ID using the second argument, so that the response is tagged with it:
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Below you can find the corresponding response header when using Varnish as reverse proxy:
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If you need to provide your controller with parameters, either in JSON or XML, the parameter struct requires an input parser so that the payload can be converted to an actual
Each payload is dispatched to its input parser based on the request's Content-Type header. For example, a request with a Content-Type of
application/vnd.ez.api.ContentCreate will be parsed by
eZ\Publish\Core\REST\Server\Input\Parser\ContentCreate. This parser will build and return a
ContentCreateStruct that can then be used to create content with the Public API.
Those input parsers are provided with a pre-parsed version of the input payload, as an associative array, and don't have to care about the actual format (XML or JSON).
Let's see what it would look like with a Content-Type of
application/vnd.my.Greetings, that would send this as XML:
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First, you need to create a service with the appropriate tag in
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The mediaType attribute of the
ezpublish\_rest.input.parser tag maps our Content Type to the input parser.
Implement your parser. It must extend
eZ\Publish\Core\REST\Server\Input\Parser, and implement the
parse() method. It accepts as an argument the input payload,
$data, as an array, and an instance of
ParsingDispatcher that can be used to forward parsing of embedded content.
For convenience, consider that your input parser returns an instance of
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You should then add a new method to the previous
DefaultController to handle the new POST request:
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inputDispatcher is responsible for matching the
Content-Type sent in the header with the Greetings
Finally, a new Route should be added to
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POST requests are not able to access the Repository without performing a user authentication. For more information check REST API Authentication.
You can look into the built-in
eZ/Publish/Core/REST/Server/Input/Parser, for more examples.
Registering resources in the REST root¶
You can register newly added resources so that they show up in the REST root resource for automatic discovery.
New resources can be registered with code like this:
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someresource being a unique key.
router.generate call dynamically renders a URI based on the name of the route and the optional parameters that are passed as the other arguments (in the code above this is the
This syntax is based on [Symfony's expression languagehttp://symfony.com/doc/3.4/components/expression_language.html), an extensible component that allows limited/readable scripting to be used outside code context.
The above configuration will add the following entry to the root resource:
<someresource media-type="application/vnd.ez.api.Content+xml" href="/api/ezp/v2/content/objects/2"/>