Issue #2666798 by dawehner: Add an entity revision parameter converter & route enhancer

core/lib/Drupal/Core/ParamConverter/EntityRevisionParamConverter.php

+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\ParamConverter\EntityRevisionParamConverter.
+ */
+
+namespace Drupal\Core\ParamConverter;
+
+use Drupal\Core\Entity\EntityTypeManagerInterface;
+use Symfony\Component\Routing\Route;
+
+/**
+ * Parameter converter for upcasting entity revision IDs to full objects.
+ *
+ * This is useful for pages which want to show a specific revision, like
+ * "/entity_example/{entity_example}/revision/{entity_example_revision}".
+ *
+ *
+ * In order to use it you should specify some additional options in your route:
+ * @code
+ * example.route:
+ *   path: /foo/{entity_example_revision}
+ *   options:
+ *     parameters:
+ *       entity_example_revision:
+ *         type: entity_revision:entity_example
+ * @endcode
+ */
+class EntityRevisionParamConverter implements ParamConverterInterface {
+
+  /**
+   * The entity type manager.
+   *
+   * @var \Drupal\Core\Entity\EntityTypeManagerInterface
+   */
+  protected $entityTypeManager;
+
+  /**
+   * Creates a new EntityRevisionParamConverter instance.
+   *
+   * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
+   *   The entity type manager.
+   */
+  public function __construct(EntityTypeManagerInterface $entity_type_manager) {
+    $this->entityTypeManager = $entity_type_manager;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function convert($value, $definition, $name, array $defaults) {
+    list (, $entity_type_id) = explode(':', $definition['type'], 2);
+    $entity_storage = $this->entityTypeManager->getStorage($entity_type_id);
+    return $entity_storage->loadRevision($value);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function applies($definition, $name, Route $route) {
+    return isset($definition['type']) && strpos($definition['type'], 'entity_revision:') !== FALSE;
+  }
+
+}

core/lib/Drupal/Core/Routing/Enhancer/EntityRevisionRouteEnhancer.php

+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Routing\Enhancer\EntityRevisionRouteEnhancer.
+ */
+
+namespace Drupal\Core\Routing\Enhancer;
+
+use Symfony\Cmf\Component\Routing\RouteObjectInterface;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\Routing\Route;
+
+/**
+ * Adds _entity_revision to the request attributes, if possible.
+ */
+class EntityRevisionRouteEnhancer implements RouteEnhancerInterface {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function applies(Route $route) {
+    // Check whether there is any entity revision parameter.
+    $parameters = $route->getOption('parameters') ?: [];
+    foreach ($parameters as $info) {
+      if (isset($info['type']) && strpos($info['type'], 'entity_revision:') === 0) {
+        return TRUE;
+      }
+    }
+    return FALSE;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function enhance(array $defaults, Request $request) {
+    /** @var \Symfony\Component\Routing\Route $route */
+    $route = $defaults[RouteObjectInterface::ROUTE_OBJECT];
+    $options = $route->getOptions();
+    if (isset($options['parameters'])) {
+      foreach ($options['parameters'] as $name => $details) {
+        if (!empty($details['type']) && strpos($details['type'], 'entity_revision:') !== FALSE) {
+          $defaults['_entity_revision'] = $defaults[$name];
+          break;
+        }
+      }
+    }
+
+    return $defaults;
+  }
+
+}

core/tests/Drupal/Tests/Core/Enhancer/EntityRevisionRouteEnhancerTest.php

+<?php
+
+/**
+ * @file
+ * Contains Drupal\Tests\Core\Enhancer\EntityRevisionRouteEnhancerTest.
+ */
+
+namespace Drupal\Tests\Core\Enhancer;
+
+use Drupal\Core\Entity\EntityInterface;
+use Drupal\Core\Routing\Enhancer\EntityRevisionRouteEnhancer;
+use Drupal\Tests\UnitTestCase;
+use Symfony\Cmf\Component\Routing\RouteObjectInterface;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\Routing\Route;
+
+/**
+ * @coversDefaultClass \Drupal\Core\Routing\Enhancer\EntityRevisionRouteEnhancer
+ * @group Entity
+ */
+class EntityRevisionRouteEnhancerTest extends UnitTestCase {
+
+  /**
+   * @var \Drupal\entity\RouteEnhancer\EntityRevisionRouteEnhancer
+   */
+  protected $routeEnhancer;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+
+    $this->routeEnhancer = new EntityRevisionRouteEnhancer();
+  }
+
+  /**
+   * @covers ::applies
+   * @dataProvider providerTestApplies
+   */
+  public function testApplies(Route $route, $expected) {
+    $this->assertEquals($expected, $this->routeEnhancer->applies($route));
+  }
+
+  public function providerTestApplies() {
+    $data = [];
+    $data['no-parameter'] = [new Route('/test-path'), FALSE];
+    $data['none-revision-parameters'] = [new Route('/test-path/{entity_test}', [], [], ['parameters' => ['entity_test' => ['type' => 'entity:entity_test']]]), FALSE];
+    $data['with-revision-parameter'] = [new Route('/test-path/{entity_test_revision}', [], [], ['parameters' => ['entity_test_revision' => ['type' => 'entity_revision:entity_test']]]), TRUE];
+
+    return $data;
+  }
+
+  /**
+   * @covers ::enhance
+   */
+  public function testEnhanceWithoutEntityRevision() {
+    $route = new Route('/test-path/{entity_test}', [], [], ['parameters' => ['entity_test' => ['type' => 'entity:entity_test']]]);
+    $request = Request::create('/test-path/123');
+    $entity = $this->prophesize(EntityInterface::class);
+
+    $defaults = [];
+    $defaults['entity_test'] = $entity->reveal();
+    $defaults[RouteObjectInterface::ROUTE_OBJECT] = $route;
+    $this->assertEquals($defaults, $this->routeEnhancer->enhance($defaults, $request));
+  }
+
+  /**
+   * @covers ::enhance
+   */
+  public function testEnhanceWithEntityRevision() {
+    $route = new Route('/test-path/{entity_test_revision}', [], [], ['parameters' => ['entity_test_revision' => ['type' => 'entity_revision:entity_test']]]);
+    $request = Request::create('/test-path/123');
+    $entity = $this->prophesize(EntityInterface::class);
+
+    $defaults = [];
+    $defaults['entity_test_revision'] = $entity->reveal();
+    $defaults[RouteObjectInterface::ROUTE_OBJECT] = $route;
+
+    $expected = $defaults;
+    $expected['_entity_revision'] = $defaults['entity_test_revision'];
+    $this->assertEquals($expected, $this->routeEnhancer->enhance($defaults, $request));
+  }
+
+}

core/tests/Drupal/Tests/Core/ParamConverter/EntityRevisionParamConverterTest.php

+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Tests\Core\ParamConverter\EntityRevisionParamConverterTest.
+ */
+
+namespace Drupal\Tests\Core\ParamConverter;
+
+use Drupal\Core\Entity\EntityInterface;
+use Drupal\Core\Entity\EntityStorageInterface;
+use Drupal\Core\Entity\EntityTypeManagerInterface;
+use Drupal\Core\ParamConverter\EntityRevisionParamConverter;
+use Drupal\Tests\UnitTestCase;
+use Symfony\Component\Routing\Route;
+
+/**
+ * @coversDefaultClass \Drupal\Core\ParamConverter\EntityRevisionParamConverter
+ * @group entity
+ */
+class EntityRevisionParamConverterTest extends UnitTestCase {
+
+  /**
+   * The tested entity revision param converter.
+   *
+   * @var \Drupal\entity\ParamConverter\EntityRevisionParamConverter
+   */
+  protected $converter;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+
+    $this->converter = new EntityRevisionParamConverter($this->prophesize(EntityTypeManagerInterface::class)->reveal());
+  }
+
+  protected function getTestRoute() {
+    $route = new Route('/test/{test_revision}');
+    $route->setOption('parameters', [
+      'test_revision' => [
+        'type' => 'entity_revision:test',
+      ],
+    ]);
+    return $route;
+  }
+
+  /**
+   * @covers ::applies
+   */
+  public function testNonApplyingRoute() {
+    $route = new Route('/test');
+    $this->assertFalse($this->converter->applies([], 'test_revision', $route));
+  }
+
+  /**
+   * @covers ::applies
+   */
+  public function testApplyingRoute() {
+    $route = $this->getTestRoute();
+    $this->assertTrue($this->converter->applies($route->getOption('parameters')['test_revision'], 'test_revision', $route));
+  }
+
+  /**
+   * @covers ::convert
+   */
+  public function testConvert() {
+    $entity = $this->prophesize(EntityInterface::class)->reveal();
+    $storage = $this->prophesize(EntityStorageInterface::class);
+    $storage->loadRevision(1)->willReturn($entity);
+
+    $entity_type_manager = $this->prophesize(EntityTypeManagerInterface::class);
+    $entity_type_manager->getStorage('test')->willReturn($storage->reveal());
+    $converter = new EntityRevisionParamConverter($entity_type_manager->reveal());
+
+    $route = $this->getTestRoute();
+    $result = $converter->convert(1, $route->getOption('parameters')['test_revision'], 'test_revision', ['test_revision' => 1]);
+    $this->assertSame($entity, $result);
+  }
+
+}