v3.1 Creating Custom Operations and Controllers

Creating Custom Operations and Controllers

Table of Contents

Note: using custom controllers with API Platform is discouraged. Also, GraphQL is not supported. For most use cases, better extension points, working both with REST and GraphQL, are available.

API Platform can leverage the Symfony routing system to register custom operations related to custom controllers. Such custom controllers can be any valid Symfony controller, including standard Symfony controllers extending the Symfony\Bundle\FrameworkBundle\Controller\AbstractController helper class.

However, API Platform recommends to use action classes instead of typical Symfony controllers. Internally, API Platform implements the Action-Domain-Responder pattern (ADR), a web-specific refinement of MVC.

The distribution of API Platform also eases the implementation of the ADR pattern: it automatically registers action classes stored in api/src/Controller as autowired services.

Thanks to the autowiring feature of the Symfony Dependency Injection container, services required by an action can be type-hinted in its constructor, it will be automatically instantiated and injected, without having to declare it explicitly.

In the following examples, the built-in GET operation is registered as well as a custom operation called post_publication.

By default, API Platform uses the first Get operation defined to generate the IRI of an item and the first GetCollection operation to generate the IRI of a collection.

If your resource does not have any Get operation, API Platform automatically adds an operation to help generating this IRI. If your resource has any identifier, this operation will look like /books/{id}. But if your resource doesn’t have any identifier, API Platform will use the Skolem format /.well-known/genid/{id}. Those routes are not exposed from any documentation (for instance OpenAPI), but are anyway declared on the Symfony routing and always return a HTTP 404.

If you create a custom operation, you will probably want to properly document it. See the OpenAPI part of the documentation to do so.

First, let’s create your custom operation:

<?php
// api/src/Controller/CreateBookPublication.php
namespace App\Controller;

use App\Entity\Book;
use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
use Symfony\Component\HttpKernel\Attribute\AsController;

#[AsController]
class CreateBookPublication extends AbstractController
{
    public function __construct(
        private BookPublishingHandler $bookPublishingHandler
    ) {}

    public function __invoke(Book $book): Book
    {
        $this->bookPublishingHandler->handle($book);

        return $book;
    }
}

This custom operation behaves exactly like the built-in operation: it returns a JSON-LD document corresponding to the ID passed in the URL.

Here we consider that autowiring is enabled for controller classes (the default when using the API Platform distribution). This action will be automatically registered as a service (the service name is the same as the class name: App\Controller\CreateBookPublication).

API Platform automatically retrieves the appropriate PHP entity using the state provider then deserializes user data in it, and for POST, PUT and PATCH requests updates the entity with state provided by the user.

The entity is retrieved in the __invoke method thanks to a dedicated argument resolver.

When using GET, the __invoke() method parameter will receive the identifier and should be called the same as the resource identifier. So for the path /user/{uuid}/bookmarks, you must use __invoke(string $uuid).

Services ($bookPublishingHandler here) are automatically injected thanks to the autowiring feature. You can type-hint any service you need and it will be autowired too.

The __invoke method of the action is called when the matching route is hit. It can return either an instance of Symfony\Component\HttpFoundation\Response (that will be displayed to the client immediately by the Symfony kernel) or, like in this example, an instance of an entity mapped as a resource (or a collection of instances for collection operations). In this case, the entity will pass through all built-in event listeners of API Platform. It will be automatically validated, persisted and serialized in JSON-LD. Then the Symfony kernel will send the resulting document to the client.

The routing has not been configured yet because we will add it at the resource configuration level:

<?php
// api/src/Entity/Book.php
namespace App\Entity;

use ApiPlatform\Metadata\ApiResource;
use ApiPlatform\Metadata\Get;
use ApiPlatform\Metadata\Post;
use App\Controller\CreateBookPublication;

#[ApiResource(operations: [
    new Get(),
    new Post(
        name: 'publication', 
        uriTemplate: '/books/{id}/publication', 
        controller: CreateBookPublication::class
    )
])]
class Book
{
    // ...
}
# api/config/api_platform/resources.yaml
resources:
    App\Entity\Book:
        operations:
            ApiPlatform\Metadata\Get: ~
            post_publication:
                class: ApiPlatform\Metadata\Post
                method: POST
                uriTemplate: /books/{id}/publication
                controller: App\Controller\CreateBookPublication
<?xml version="1.0" encoding="UTF-8" ?>
<!-- api/config/api_platform/resources.xml -->

<resources
        xmlns="https://api-platform.com/schema/metadata/resources-3.0"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="https://api-platform.com/schema/metadata/resources-3.0
        https://api-platform.com/schema/metadata/resources-3.0.xsd">
    <resource class="App\Entity\Book">
        <operations>
            <operation class="ApiPlatform\Metadata\Get" />
            <operation class="ApiPlatform\Metadata\Post" name="post_publication" uriTemplate="/books/{id}/publication"
                       controller="App\Controller\CreateBookPublication" />
        </operations>
    </resource>
</resources>

It is mandatory to set the method, uriTemplate and controller attributes. They allow API Platform to configure the routing path and the associated controller respectively.

# Using the PlaceholderAction

Complex use cases may lead you to create multiple custom operations.

In such a case, you will probably create the same amount of custom controllers while you may not need to perform custom logic inside.

To avoid that, API Platform provides the ApiPlatform\Action\PlaceholderAction which behaves the same when using the built-in operations.

You just need to set the controller attribute with this class. Here, the previous example updated:

// api/src/Entity/Book.php
namespace App\Entity;

use ApiPlatform\Action\PlaceholderAction;
use ApiPlatform\Metadata\ApiResource;
use ApiPlatform\Metadata\Get;
use ApiPlatform\Metadata\Post;

#[ApiResource(operations: [
    new Get(),
    new Post(
        name: 'publication', 
        uriTemplate: '/books/{id}/publication', 
        controller: PlaceholderAction::class
    )
])]
class Book
{
    // ...
}
# api/config/api_platform/resources.yaml
resources:
    App\Entity\Book:
        operations:
            ApiPlatform\Metadata\Get: ~
            post_publication:
                class: ApiPlatform\Metadata\Post
                method: POST
                uriTemplate: /books/{id}/publication
                controller: ApiPlatform\Action\PlaceholderAction
<?xml version="1.0" encoding="UTF-8" ?>
<!-- api/config/api_platform/resources.xml -->

<resources
        xmlns="https://api-platform.com/schema/metadata/resources-3.0"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="https://api-platform.com/schema/metadata/resources-3.0
        https://api-platform.com/schema/metadata/resources-3.0.xsd">
    <resource class="App\Entity\Book">
        <operations>
            <operation class="ApiPlatform\Metadata\Get" />
            <operation class="ApiPlatform\Metadata\Post" name="post_publication" uriTemplate="/books/{id}/publication"
                       controller="ApiPlatform\Action\PlaceholderAction" />
        </operations>
    </resource>
</resources>

# Using Serialization Groups

You may want different serialization groups for your custom operations. Just configure the proper normalizationContext and/or denormalizationContext in your operation:

<?php
// api/src/Entity/Book.php
namespace App\Entity;

use ApiPlatform\Metadata\ApiResource;
use ApiPlatform\Metadata\Get;
use ApiPlatform\Metadata\Post;
use App\Controller\CreateBookPublication;
use Symfony\Component\Serializer\Annotation\Groups;

#[ApiResource(operations: [
    new Get(),
    new Post(
        name: 'publication', 
        uriTemplate: '/books/{id}/publication', 
        controller: CreateBookPublication::class, 
        normalizationContext: ['groups' => ['publication']],
    )
])]
class Book
{
    // ...

    #[Groups(['publication'])]
    public $isbn;

    // ...
}
# api/config/api_platform/resources.yaml
resources:
    App\Entity\Book:
        operations:
            ApiPlatform\Metadata\Get: ~
            post_publication:
                class: ApiPlatform\Metadata\Get
                uriTemplate: /books/{id}/publication
                controller: App\Controller\CreateBookPublication
                normalizationContext:
                    groups: ['publication']
<?xml version="1.0" encoding="UTF-8" ?>
<!-- api/config/api_platform/resources.xml -->

<resources xmlns="https://api-platform.com/schema/metadata/resources-3.0"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="https://api-platform.com/schema/metadata/resources-3.0
        https://api-platform.com/schema/metadata/resources-3.0.xsd">
    <resource class="App\Entity\Book">
        <operations>
            <operation class="ApiPlatform\Metadata\Get" />
            <operation class="ApiPlatform\Metadata\Post" name="post_publication" uriTemplate="/books/{id}/publication"
                controller="App\Controller\CreateBookPublication">
                <normalizationContext>
                    <values>
                        <value name="groups">publication</value>
                    </values>
                </normalizationContext>
            </operation>
        </operations>
    </resource>
</resources>

# Retrieving the Entity

If you want to bypass the automatic retrieval of the entity in your custom operation, you can set read: false in the operation attribute:

<?php
// api/src/Entity/Book.php
namespace App\Entity;

use ApiPlatform\Metadata\ApiResource;
use ApiPlatform\Metadata\Get;
use ApiPlatform\Metadata\Post;
use App\Controller\CreateBookPublication;

#[ApiResource(operations: [
    new Get(),
    new Post(
        name: 'publication', 
        uriTemplate: '/books/{id}/publication', 
        controller: CreateBookPublication::class, 
        read: false
    )
])]
class Book
{
    // ...
}
# api/config/api_platform/resources.yaml
resources:
    App\Entity\Book:
        operations:
            ApiPlatform\Metadata\Get: ~
            post_publication:
                class: ApiPlatform\Metadata\Post
                uriTemplate: /books/{id}/publication
                controller: App\Controller\CreateBookPublication
                read: false
<?xml version="1.0" encoding="UTF-8" ?>
<!-- api/config/api_platform/resources.xml -->

<resources xmlns="https://api-platform.com/schema/metadata/resources-3.0"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="https://api-platform.com/schema/metadata/resources-3.0
        https://api-platform.com/schema/metadata/resources-3.0.xsd">
    <resource class="App\Entity\Book">
        <operations>
            <operation class="ApiPlatform\Metadata\Get" />
            <operation class="ApiPlatform\Metadata\Post" name="post_publication" uriTemplate="/books/{id}/publication"
                controller="App\Controller\CreateBookPublication" read="false" />
        </operations>
    </resource>
</resources>

This way, it will skip the ReadListener. You can do the same for some other built-in listeners. See Built-in Event Listeners for more information.

In your custom controller, the __invoke() method parameter should be called the same as the entity identifier. So for the path /user/{uuid}/bookmarks, you must use __invoke(string $uuid).

# Alternative Method

There is another way to create a custom operation. However, we do not encourage its use. Indeed, this one disperses the configuration at the same time in the routing and the resource configuration.

The post_publication operation references the Symfony route named book_post_publication.

Since version 2.3, you can also use the route name as operation name by convention, as shown in the following example for book_post_discontinuation when neither method nor routeName attributes are specified.

First, let’s create your resource configuration:

<?php
// api/src/Entity/Book.php
namespace App\Entity;

use ApiPlatform\Metadata\ApiResource;
use ApiPlatform\Metadata\Get;
use ApiPlatform\Metadata\Post;

#[ApiResource(operations: [
    new Get(),
    new Post(name: 'publication', routeName: 'book_post_publication'),
    new Post(name: 'book_post_discontinuation')
])]
class Book
{
    // ...
}
# api/config/api_platform/resources.yaml
resources:
    App\Entity\Book:
        operations:
            ApiPlatform\Metadata\Get: ~
            post_publication:
                class: ApiPlatform\Metadata\Post
                routeName: book_post_publication
            book_post_discontinuation:
              class: ApiPlatform\Metadata\Post
<?xml version="1.0" encoding="UTF-8" ?>
<!-- api/config/api_platform/resources.xml -->

<resources xmlns="https://api-platform.com/schema/metadata/resources-3.0"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="https://api-platform.com/schema/metadata/resources-3.0
        https://api-platform.com/schema/metadata/resources-3.0.xsd">
    <resource class="App\Entity\Book">
        <operations>
            <operation class="ApiPlatform\Metadata\Get" />
            <operation class="ApiPlatform\Metadata\Post" name="post_publication" routeName="book_post_publication" />
            <operation class="ApiPlatform\Metadata\Post" name="book_post_discontinuation" />
        </operations>
    </resource>
</resources>

API Platform will automatically map this post_publication operation to the route book_post_publication. Let’s create a custom action and its related route using attributes:

<?php
// api/src/Controller/CreateBookPublication.php
namespace App\Controller;

use App\Entity\Book;
use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
use Symfony\Component\HttpKernel\Attribute\AsController;
use Symfony\Component\Routing\Annotation\Route;

#[AsController]
class CreateBookPublication extends AbstractController
{
    public function __construct(
        private BookPublishingHandler $bookPublishingHandler
    ) {}

    #[Route(
        name: 'book_post_publication',
        path: '/books/{id}/publication',
        methods: ['POST'],
        defaults: [
            '_api_resource_class' => Book::class,
            '_api_operation_name' => '_api_/books/{id}/publication_post',
        ],
    )]
    public function __invoke(Book $book): Book
    {
        $this->bookPublishingHandler->handle($book);

        return $book;
    }
}

It is mandatory to set _api_resource_class and _api_operation_name in the parameters of the route (defaults key). It allows API Platform to work with the Symfony routing system.

Alternatively, you can also use a traditional Symfony controller and YAML or XML route declarations. The following example does the same thing as the previous example:

<?php
// api/src/Controller/BookController.php
namespace App\Controller;

use App\Entity\Book;
use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
use Symfony\Component\HttpKernel\Attribute\AsController;

#[AsController]
class BookController extends AbstractController
{
    public function createPublication(Book $book, BookPublishingHandler $bookPublishingHandler): Book
    {
        return $bookPublishingHandler->handle($book);
    }
}
# api/config/routes.yaml
book_post_publication:
    path: /books/{id}/publication
    methods: ['POST']
    defaults:
        _controller: App\Controller\BookController::createPublication
        _api_resource_class: App\Entity\Book
        _api_operation_name: post_publication

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