feat(state): add headers to comply with LDP specification

src/Laravel/ApiPlatformProvider.php

@@ -146,6 +146,7 @@
 use ApiPlatform\State\Pagination\Pagination;
 use ApiPlatform\State\Pagination\PaginationOptions;
 use ApiPlatform\State\Processor\AddLinkHeaderProcessor;
+use ApiPlatform\State\Processor\LinkedDataPlatformProcessor;
 use ApiPlatform\State\Processor\RespondProcessor;
 use ApiPlatform\State\Processor\SerializeProcessor;
 use ApiPlatform\State\Processor\WriteProcessor;
@@ -424,6 +425,14 @@ public function register(): void
             return new AddLinkHeaderProcessor($decorated, new HttpHeaderSerializer());
         });
 
+        $this->app->singleton(LinkedDataPlatformProcessor::class, function (Application $app) {
+            return new LinkedDataPlatformProcessor(
+                $app->make(AddLinkHeaderProcessor::class), // Original service
+                $app->make(ResourceClassResolverInterface::class),
+                $app->make(ResourceMetadataCollectionFactoryInterface::class)
+            );
+        });
+
         $this->app->singleton(SerializeProcessor::class, function (Application $app) {
             return new SerializeProcessor($app->make(RespondProcessor::class), $app->make(Serializer::class), $app->make(SerializerContextBuilderInterface::class));
         });

src/State/Processor/LinkedDataPlatformProcessor.php

@@ -0,0 +1,78 @@
+<?php
+
+/*
+ * This file is part of the API Platform project.
+ *
+ * (c) Kévin Dunglas <dunglas@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace ApiPlatform\State\Processor;
+
+use ApiPlatform\Metadata\Error;
+use ApiPlatform\Metadata\HttpOperation;
+use ApiPlatform\Metadata\Operation;
+use ApiPlatform\Metadata\Resource\Factory\ResourceMetadataCollectionFactoryInterface;
+use ApiPlatform\Metadata\ResourceClassResolverInterface;
+use ApiPlatform\State\ProcessorInterface;
+use Symfony\Component\HttpFoundation\Response;
+
+/**
+ * @template T1
+ * @template T2
+ *
+ * @implements ProcessorInterface<T1, T2>
+ */
+final class LinkedDataPlatformProcessor implements ProcessorInterface
+{
+    private const DEFAULT_ALLOWED_METHODS = ['OPTIONS', 'HEAD'];
+
+    /**
+     * @param ProcessorInterface<T1, T2> $decorated
+     */
+    public function __construct(
+        private readonly ProcessorInterface $decorated,
+        private readonly ResourceClassResolverInterface $resourceClassResolver,
+        private readonly ResourceMetadataCollectionFactoryInterface $resourceMetadataCollectionFactory,
+    ) {
+    }
+
+    public function process(mixed $data, Operation $operation, array $uriVariables = [], array $context = []): mixed
+    {
+        $response = $this->decorated->process($data, $operation, $uriVariables, $context);
+        if (
+            !$response instanceof Response
+            || !$operation instanceof HttpOperation
+            || $operation instanceof Error
+            || !$operation->getUriTemplate()
+            || !$this->resourceClassResolver->isResourceClass($operation->getClass())
+        ) {
+            return $response;
+        }
+
+        $acceptPost = null;
+        $allowedMethods = self::DEFAULT_ALLOWED_METHODS;
+        $resourceCollection = $this->resourceMetadataCollectionFactory->create($operation->getClass());
+        foreach ($resourceCollection as $resource) {
+            foreach ($resource->getOperations() as $op) {
+                if ($op->getUriTemplate() === $operation->getUriTemplate()) {
+                    $allowedMethods[] = $method = $op->getMethod();
+                    if ('POST' === $method && \is_array($outputFormats = $op->getOutputFormats())) {
+                        $acceptPost = implode(', ', array_merge(...array_values($outputFormats)));
+                    }
+                }
+            }
+        }
+        if ($acceptPost) {
+            $response->headers->set('Accept-Post', $acceptPost);
+        }
+
+        $response->headers->set('Allow', implode(', ', $allowedMethods));
+
+        return $response;
+    }
+}

src/State/Tests/Fixtures/ApiResource/Dummy.php

@@ -0,0 +1,22 @@
+<?php
+
+/*
+ * This file is part of the API Platform project.
+ *
+ * (c) Kévin Dunglas <dunglas@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace ApiPlatform\State\Tests\Fixtures\ApiResource;
+
+use ApiPlatform\Metadata\ApiResource;
+
+#[ApiResource()]
+class Dummy
+{
+    public int $id;
+}

src/State/Tests/Processor/LinkedDataPlatformProcessorTest.php

@@ -0,0 +1,161 @@
+<?php
+
+/*
+ * This file is part of the API Platform project.
+ *
+ * (c) Kévin Dunglas <dunglas@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace ApiPlatform\State\Tests\Processor;
+
+use ApiPlatform\Hal\Tests\Fixtures\Dummy;
+use ApiPlatform\Metadata\ApiResource;
+use ApiPlatform\Metadata\Delete;
+use ApiPlatform\Metadata\Error;
+use ApiPlatform\Metadata\Get;
+use ApiPlatform\Metadata\GetCollection;
+use ApiPlatform\Metadata\Post;
+use ApiPlatform\Metadata\Put;
+use ApiPlatform\Metadata\Resource\Factory\ResourceMetadataCollectionFactoryInterface;
+use ApiPlatform\Metadata\Resource\ResourceMetadataCollection;
+use ApiPlatform\Metadata\ResourceClassResolverInterface;
+use ApiPlatform\State\Processor\LinkedDataPlatformProcessor;
+use ApiPlatform\State\ProcessorInterface;
+use PHPUnit\Framework\MockObject\MockObject;
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\Response;
+
+class LinkedDataPlatformProcessorTest extends TestCase
+{
+    private ResourceMetadataCollectionFactoryInterface&MockObject $resourceMetadataCollectionFactory;
+
+    private ResourceClassResolverInterface&MockObject $resourceClassResolver;
+
+    private ProcessorInterface&MockObject $decorated;
+
+    protected function setUp(): void
+    {
+        $this->resourceClassResolver = $this->createMock(ResourceClassResolverInterface::class);
+        $this->resourceClassResolver
+            ->method('isResourceClass')
+            ->willReturn(true);
+
+        $this->resourceMetadataCollectionFactory = $this->createMock(ResourceMetadataCollectionFactoryInterface::class);
+        $this->resourceMetadataCollectionFactory
+            ->method('create')
+            ->willReturn(
+                new ResourceMetadataCollection(Dummy::class, [
+                    new ApiResource(operations: [
+                        new Get(uriTemplate: '/dummy/{dummyResourceId}{._format}', class: Dummy::class, name: 'get'),
+                        new GetCollection(uriTemplate: '/dummy{._format}', class: Dummy::class, name: 'get_collections'),
+                        new Post(uriTemplate: '/dummy{._format}', outputFormats: ['jsonld' => ['application/ld+json'], 'text/turtle' => ['text/turtle']], class: Dummy::class, name: 'post'),
+                        new Delete(uriTemplate: '/dummy/{dummyResourceId}{._format}', class: Dummy::class, name: 'delete'),
+                        new Put(uriTemplate: '/dummy/{dummyResourceId}{._format}', class: Dummy::class, name: 'put'),
+                    ]),
+                ])
+            );
+
+        $this->decorated = $this->createMock(ProcessorInterface::class);
+        $this->decorated->method('process')->willReturn(new Response());
+    }
+
+    public function testHeadersAcceptPostIsReturnWhenPostAllowed(): void
+    {
+        $operation = new Get('/dummy{._format}', class: Dummy::class);
+
+        $context = $this->getContext();
+
+        $processor = new LinkedDataPlatformProcessor(
+            $this->decorated,
+            $this->resourceClassResolver,
+            $this->resourceMetadataCollectionFactory
+        );
+        /** @var Response $response */
+        $response = $processor->process(null, $operation, [], $context);
+
+        $this->assertSame('application/ld+json, text/turtle', $response->headers->get('Accept-Post'));
+    }
+
+    public function testHeadersAcceptPostIsNotSetWhenPostIsNotAllowed(): void
+    {
+        $operation = new Get('/dummy/{dummyResourceId}{._format}', class: Dummy::class);
+        $context = $this->getContext();
+
+        $processor = new LinkedDataPlatformProcessor(
+            $this->decorated,
+            $this->resourceClassResolver,
+            $this->resourceMetadataCollectionFactory
+        );
+        /** @var Response $response */
+        $response = $processor->process(null, $operation, [], $context);
+
+        $this->assertNull($response->headers->get('Accept-Post'));
+    }
+
+    public function testHeaderAllowReflectsResourceAllowedMethods(): void
+    {
+        $operation = new Get('/dummy{._format}', class: Dummy::class);
+        $context = $this->getContext();
+
+        $processor = new LinkedDataPlatformProcessor(
+            $this->decorated,
+            $this->resourceClassResolver,
+            $this->resourceMetadataCollectionFactory
+        );
+        /** @var Response $response */
+        $response = $processor->process(null, $operation, [], $context);
+        $allowHeader = $response->headers->get('Allow');
+        $this->assertStringContainsString('OPTIONS', $allowHeader);
+        $this->assertStringContainsString('HEAD', $allowHeader);
+        $this->assertStringContainsString('GET', $allowHeader);
+        $this->assertStringContainsString('POST', $allowHeader);
+        $operation = new Get('/dummy/{dummyResourceId}{._format}', class: Dummy::class);
+
+        /** @var Response $response */
+        $processor = new LinkedDataPlatformProcessor(
+            $this->decorated,
+            $this->resourceClassResolver,
+            $this->resourceMetadataCollectionFactory
+        );
+        /** @var Response $response */
+        $response = $processor->process('data', $operation, [], $this->getContext());
+        $allowHeader = $response->headers->get('Allow');
+        $this->assertStringContainsString('OPTIONS', $allowHeader);
+        $this->assertStringContainsString('HEAD', $allowHeader);
+        $this->assertStringContainsString('GET', $allowHeader);
+        $this->assertStringContainsString('PUT', $allowHeader);
+        $this->assertStringContainsString('DELETE', $allowHeader);
+    }
+
+    public function testProcessorWithoutRequiredConditionReturnOriginalResponse(): void
+    {
+        // Operation is an Error
+        $processor = new LinkedDataPlatformProcessor($this->decorated, $this->resourceClassResolver, $this->resourceMetadataCollectionFactory);
+        $response = $processor->process(null, new Error(), $this->getContext());
+        $this->assertNull($response->headers->get('Allow'));
+    }
+
+    private function createGetRequest(): Request
+    {
+        $request = new Request();
+        $request->setMethod('GET');
+        $request->setRequestFormat('json');
+        $request->headers->set('Accept', 'application/ld+json');
+
+        return $request;
+    }
+
+    private function getContext(): array
+    {
+        return [
+            'resource_class' => Dummy::class,
+            'request' => $this->createGetRequest(),
+        ];
+    }
+}

src/Symfony/Bundle/Resources/config/state/processor.xml

@@ -26,5 +26,11 @@
         <service id="api_platform.state_processor.add_link_header" class="ApiPlatform\State\Processor\AddLinkHeaderProcessor" decorates="api_platform.state_processor.respond">
             <argument type="service" id="api_platform.state_processor.add_link_header.inner" />
         </service>
+
+        <service id="api_platform.state_processor.linked_data_platform" class="ApiPlatform\State\Processor\LinkedDataPlatformProcessor" decorates="api_platform.state_processor.respond">
+            <argument type="service" id="api_platform.state_processor.linked_data_platform.inner" />
+            <argument type="service" id="api_platform.resource_class_resolver" />
+            <argument type="service" id="api_platform.metadata.resource.metadata_collection_factory" />
+        </service>
     </services>
 </container>

src/Symfony/Bundle/Resources/config/symfony/events.xml

@@ -73,6 +73,12 @@
             <argument type="service" id="api_platform.state_processor.add_link_header.inner" />
         </service>
 
+        <service id="api_platform.state_processor.linked_data_platform" class="ApiPlatform\State\Processor\LinkedDataPlatformProcessor" decorates="api_platform.state_processor.respond">
+            <argument type="service"  id="api_platform.state_processor.linked_data_platform.inner" />
+            <argument type="service" id="api_platform.resource_class_resolver" />
+            <argument type="service" id="api_platform.metadata.resource.metadata_collection_factory" />
+        </service>
+
         <service id="api_platform.listener.view.write" class="ApiPlatform\Symfony\EventListener\WriteListener">
             <argument type="service" id="api_platform.state_processor.write" />
             <argument type="service" id="api_platform.metadata.resource.metadata_collection_factory" />

tests/Fixtures/TestBundle/ApiResource/DummyGetPostDeleteOperation.php

@@ -0,0 +1,63 @@
+<?php
+
+/*
+ * This file is part of the API Platform project.
+ *
+ * (c) Kévin Dunglas <dunglas@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace ApiPlatform\Tests\Fixtures\TestBundle\ApiResource;
+
+use ApiPlatform\Metadata\ApiResource;
+use ApiPlatform\Metadata\Delete;
+use ApiPlatform\Metadata\Get;
+use ApiPlatform\Metadata\GetCollection;
+use ApiPlatform\Metadata\Operation;
+use ApiPlatform\Metadata\Post;
+
+#[ApiResource(operations: [
+    new Get(
+        uriTemplate: '/dummy_get_post_delete_operations/{id}',
+        provider: [self::class, 'provideItem'],
+    ),
+    new GetCollection(
+        uriTemplate: '/dummy_get_post_delete_operations',
+        provider: [self::class, 'provide'], ),
+    new Post(
+        uriTemplate: '/dummy_get_post_delete_operations',
+        provider: [self::class, 'provide'], ),
+    new Delete(
+        uriTemplate: '/dummy_get_post_delete_operations/{id}',
+        provider: [self::class, 'provideItem'], ),
+])]
+class DummyGetPostDeleteOperation
+{
+    public ?int $id;
+
+    public ?string $name = null;
+
+    public static function provide(Operation $operation, array $uriVariables = [], array $context = []): array
+    {
+        $dummyResource = new self();
+        $dummyResource->id = 1;
+        $dummyResource->name = 'Dummy name';
+
+        return [
+            $dummyResource,
+        ];
+    }
+
+    public static function provideItem(Operation $operation, array $uriVariables = [], array $context = []): self
+    {
+        $dummyResource = new self();
+        $dummyResource->id = $uriVariables['id'];
+        $dummyResource->name = 'Dummy name';
+
+        return $dummyResource;
+    }
+}