Add Laravel support to state providers documentation (#2018)

Co-authored-by: Antoine Bluchet <soyuka@users.noreply.github.com>

Author: vinceAmstoutz

core/state-providers.md

@@ -1,24 +1,36 @@
 # State Providers
 
-To retrieve data exposed by the API, API Platform uses classes called **state providers**. A state provider using [Doctrine
-ORM](https://www.doctrine-project.org/projects/orm.html) to retrieve data from a database, a state provider using
+To retrieve data exposed by the API, API Platform uses classes called **state providers**.
+
+With the Symfony variant, a state provider using [Doctrine
+ORM](https://www.doctrine-project.org/projects/orm.html) is ready to retrieve data from a database and a state provider using
 [Doctrine MongoDB ODM](https://www.doctrine-project.org/projects/mongodb-odm.html) to retrieve data from a document
-database, and a state provider using [Elasticsearch-PHP](https://www.elastic.co/guide/en/elasticsearch/client/php-api/current/index.html)
-to retrieve data from an Elasticsearch cluster are included with the library. The first one is enabled by default. These
-state providers natively support paged collections and filters. They can be used as-is and are perfectly suited to common uses.
+database.
+
+With the Laravel variant, a state provider using [Eloquent ORM](https://laravel.com/docs/eloquent) to retrieve data from a relational database and a state provider.
+
+The ORM providers are enabled by default, based on your framework variant (Eloquent or Doctrine will be set up).
+
+
+These state providers natively support paged collections and filters. They can be used as-is and are perfectly suited to common uses.
 
 However, you sometimes want to retrieve data from other sources such as another persistence layer or a webservice.
 Custom state providers can be used to do so. A project can include as many state providers as needed. The first able to
 retrieve data for a given resource will be used.
 
 To do so you need to implement the `ApiPlatform\State\ProviderInterface`.
 
-In the following examples we will create custom state providers for an entity class called `App\Entity\BlogPost`.
-Note, that if your entity is not Doctrine-related, you need to flag the identifier property by using
+In the following examples we will create custom state providers for Symfony entities and Laravel models:
+- For Symfony we will create an entity class called `App\Entity\BlogPost`.
+- For Laravel, we will create a model class called `App\Models\BlogPost`.
+
+Note, that if your entity is not Doctrine-related or Eloquent-related, you need to flag the identifier property by using
 `#[ApiProperty(identifier: true)` for things to work properly (see also [Entity Identifier Case](serialization.md#entity-identifier-case)).
 
 ## Creating a Custom State Provider
 
+### Custom State Provider with Symfony
+
 If the [Symfony MakerBundle](https://symfony.com/doc/current/bundles/SymfonyMakerBundle) is installed in your project,
 you can use the following command to generate a custom state provider easily:
 
@@ -114,7 +126,7 @@ final class BlogPostProvider implements ProviderInterface
 }
 ```
 
-We then need to configure this same provider on the BlogPost `GetCollection` operation, or for every operations via the `ApiResource` attribute:
+We then need to configure this same provider on the BlogPost `GetCollection` operation, or for every operation via the `ApiResource` attribute:
 
 ```php
 <?php
@@ -129,11 +141,124 @@ use App\State\BlogPostProvider;
 class BlogPost {}
 ```
 
+#### Custom State Provider with Laravel
+
+Using [Laravel Artisan Console](https://laravel.com/docs/artisan), you can generate a custom state provider easily with the following command:
+
+```console
+php artisan make:state-provider
+```
+
+Let's start with a State Provider for the URI: `/blog_posts/{id}`.
+
+First, your `BlogPostProvider` has to implement the
+[`ProviderInterface`](https://github.com/api-platform/core/blob/main/src/State/ProviderInterface.php):
+
+```php
+<?php
+// api/src/State/BlogPostProvider.php
+
+namespace App\State;
+
+use App\Models\BlogPost;
+use ApiPlatform\Metadata\Operation;
+use ApiPlatform\State\ProviderInterface;
+
+/**
+ * @implements ProviderInterface<BlogPost|null>
+ */
+final class BlogPostProvider implements ProviderInterface
+{
+    private const DATA = [
+        'ab' => new BlogPost('ab'),
+        'cd' => new BlogPost('cd'),
+    ];
+
+    public function provide(Operation $operation, array $uriVariables = [], array $context = []): BlogPost|null
+    {
+        return self::DATA[$uriVariables['id']] ?? null;
+    }
+}
+```
+
+For the example, we store the list of our blog posts in an associative array (the `BlogPostProvider::DATA` constant).
+
+As this operation expects a `BlogPost`, the `provide` methods return the instance of the `BlogPost` corresponding to the ID passed in the URL. If the ID doesn't exist in the associative array, `provide()` returns `null`. API Platform will automatically generate a 404 response if the provider returns `null`.
+
+The `$uriVariables` parameter contains an array with the values of the URI variables.
+
+To use this provider we need to configure the provider on the operation:
+
+```php
+<?php
+// api/src/Models/BlogPost.php
+
+namespace App\Models;
+
+use ApiPlatform\Metadata\Get;
+use App\State\BlogPostProvider;
+
+#[Get(provider: BlogPostProvider::class)]
+class BlogPost {}
+```
+
+Now let's say that we also want to handle the `/blog_posts` URI which returns a collection. We can change the Provider into
+supporting a wider range of operations. Then we can provide a collection of blog posts when the operation is a `CollectionOperationInterface`:
+
+```php
+<?php
+// api/src/State/BlogPostProvider.php
+
+namespace App\State;
+
+use App\Models\BlogPost;
+use ApiPlatform\Metadata\Operation;
+use ApiPlatform\State\ProviderInterface;
+use ApiPlatform\Metadata\CollectionOperationInterface;
+
+/**
+ * @implements ProviderInterface<BlogPost[]|BlogPost|null>
+ */
+final class BlogPostProvider implements ProviderInterface
+{
+    private const DATA = [
+        'ab' => new BlogPost('ab'),
+        'cd' => new BlogPost('cd'),
+    ];
+
+    public function provide(Operation $operation, array $uriVariables = [], array $context = []): iterable|BlogPost|null
+    {
+        if ($operation instanceof CollectionOperationInterface) {
+            return self::DATA;
+        }
+
+        return self::DATA[$uriVariables['id']] ?? null;
+    }
+}
+```
+
+We then need to configure this same provider on the BlogPost `GetCollection` operation, or for every operation via the `ApiResource` attribute:
+
+```php
+<?php
+// api/src/Models/BlogPost.php
+
+namespace App\Models;
+
+use ApiPlatform\Metadata\ApiResource;
+use App\State\BlogPostProvider;
+
+#[ApiResource(provider: BlogPostProvider::class)]
+class BlogPost {}
+```
+
 ## Hooking into the Built-In State Provider
 
 If you want to execute custom business logic before or after retrieving data, this can be achieved by [decorating](https://symfony.com/doc/current/service_container/service_decoration.html) the built-in state providers or using [composition](https://en.wikipedia.org/wiki/Object_composition).
 
-The next example uses a [DTO](https://api-platform.com/docs/core/dto/#using-data-transfer-objects-dtos) to change the presentation for data originally retrieved by the default state provider.
+The next examples (one for  Symfony and one for Laravel) uses a [DTO](https://api-platform.com/docs/core/dto/#using-data-transfer-objects-dtos) to change the presentation for data originally retrieved by the default state provider.
+
+### Symfony State Provider mechanism
 
 ```php
 <?php
@@ -142,7 +267,7 @@ The next example uses a [DTO](https://api-platform.com/docs/core/dto/#using-data
 namespace App\State;
 
 use App\Dto\AnotherRepresentation;
-use App\Model\Book;
+use App\Entity\Book;
 use ApiPlatform\Metadata\Operation;
 use ApiPlatform\State\ProviderInterface;
 use Symfony\Component\DependencyInjection\Attribute\Autowire;
@@ -187,7 +312,86 @@ use App\State\BookRepresentationProvider;
 class Book {}
 ```
 
-## Registering Services Without Autowiring
+#### Laravel State Provider mechanism
+
+First, don't forget to tag the service with the `ProviderInterface`
+
+```php
+<?php
+
+namespace App\Providers;
+
+use ApiPlatform\State\ProviderInterface;
+use App\State\BookStateProvider;
+use Illuminate\Support\ServiceProvider;
+
+class AppServiceProvider extends ServiceProvider
+{
+    public function register(): void
+    {
+        $this->app->tag([BookRepresentationProvider::class], ProviderInterface::class);
+    }
+
+    public function boot(): void
+    {
+    }
+}
+```
+
+After that, you can inject the `ProviderInterface`
+```php
+<?php
+// api/src/State/BlogPostProvider.php
+
+namespace App\State;
+
+use App\Dto\AnotherRepresentation;
+use App\Models\Book;
+use ApiPlatform\Metadata\Operation;
+use ApiPlatform\State\ProviderInterface;
+use Symfony\Component\DependencyInjection\Attribute\Autowire;
+
+/**
+ * @implements ProviderInterface<AnotherRepresentation>
+ */
+final class BookRepresentationProvider implements ProviderInterface
+{
+    public function __construct(
+        private ProviderInterface $itemProvider,
+    )
+    {
+    }
+    
+    public function provide(Operation $operation, array $uriVariables = [], array $context = []): AnotherRepresentation
+    {
+        $book = $this->itemProvider->provide($operation, $uriVariables, $context);
+        
+        return new AnotherRepresentation(
+            // Add DTO constructor params here.
+            // $book->getTitle(),
+        );
+    }
+}
+```
+
+And configure that you want to use this provider on the Book resource:
+
+```php
+<?php
+// api/app/Models/Book.php
+
+namespace App\Models;
+
+use ApiPlatform\Metadata\Get;
+use App\Dto\AnotherRepresentation;
+use App\State\BookRepresentationProvider;
+
+#[Get(output: AnotherRepresentation::class, provider: BookRepresentationProvider::class)]
+class Book {}
+```
+
+
+## Registering Services Without Autowiring (only for the Symfony variant)
 
 The services in the previous examples are automatically registered because
 [autowiring](https://symfony.com/doc/current/service_container/autowiring.html)