provide support to export entities with all its references

drush/default_content.drush.inc

@@ -18,6 +18,19 @@ function default_content_drush_command() {
     'options' => [
       'file' => dt('Write out the exported content to a file instead of stdout'),
     ],
+    'aliases' => array('dce'),
+    'required-arguments' => 2,
+  ];
+  $items['default-content-export-references'] = [
+    'description' => dt('Exports an entity and all its referenced entities.'),
+    'arguments' => [
+      'entity_type' => dt('The entity type to export.'),
+      'entity_id' => dt('The ID of the entity to export.'),
+    ],
+    'options' => [
+      'folder' => dt('Folder to export to, entities are grouped by entity type into directories.'),
+    ],
+    'aliases' => array('dcer'),
     'required-arguments' => 2,
   ];
 
@@ -31,9 +44,6 @@ function default_content_drush_command() {
  *   The entity type ID.
  * @param $entity_id
  *   The entity ID to export.
- *
- * @return string
- *   The rendered export as hal.
  */
 function drush_default_content_export($entity_type_id, $entity_id) {
   /** @var \Drupal\default_content\DefaultContentManagerInterface $manager */
@@ -47,3 +57,28 @@ function drush_default_content_export($entity_type_id, $entity_id) {
     drush_print($export);
   }
 }
+
+/**
+ * Exports a piece of content and all its referenced entities.
+ *
+ * @param string $entity_type_id
+ *   The entity type ID.
+ * @param $entity_id
+ *   The entity ID to export.
+ */
+function drush_default_content_export_references($entity_type_id, $entity_id) {
+  /** @var \Drupal\default_content\DefaultContentManagerInterface $manager */
+  $manager = \Drupal::service('default_content.manager');
+
+  $folder = drush_get_option('folder', '.');
+
+  $serialized_by_type = $manager->exportContentWithReferences($entity_type_id, $entity_id);
+  foreach ($serialized_by_type as $entity_type => $serialized_entities) {
+    // Ensure that the folder per entity type exists.
+    $entity_type_folder = "$folder/$entity_type";
+    file_prepare_directory($entity_type_folder, FILE_CREATE_DIRECTORY);
+    foreach ($serialized_entities as $entity_id => $serialized_entity) {
+      file_put_contents($entity_type_folder . '/' . $entity_id . '.json', $serialized_entity);
+    }
+  }
+}

src/DefaultContentManager.php

@@ -7,7 +7,11 @@
 
 namespace Drupal\default_content;
 
+use Drupal\Core\Config\Entity\ConfigEntityInterface;
+use Drupal\Core\Entity\ContentEntityInterface;
 use Drupal\Core\Entity\EntityManager;
+use Drupal\Core\Field\EntityReferenceFieldItemListInterface;
+use Drupal\Core\Field\Plugin\Field\FieldType\EntityReferenceItem;
 use Drupal\Core\Session\AccountInterface;
 use Drupal\rest\Plugin\Type\ResourcePluginManager;
 use Gliph\Graph\DirectedAdjacencyList;
@@ -165,6 +169,57 @@ class DefaultContentManager implements DefaultContentManagerInterface {
     return $this->serializer->serialize($entity, 'hal_json', ['json_encode_options' => JSON_PRETTY_PRINT]);
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function exportContentWithReferences($entity_type_id, $entity_id) {
+    $storage = $this->entityManager->getStorage($entity_type_id);
+    $entity = $storage->load($entity_id);
+    /** @var \Drupal\Core\Entity\ContentEntityInterface[] $entities */
+    $entities = [$entity];
+    $entities = array_merge($entities, $this->getEntityReferencesRecursive($entity));
+
+    $serialized_entities_per_type = [];
+    // Serialize all entities and key them by entity TYPE and uuid.
+    foreach ($entities as $entity) {
+      $serialized_entities_per_type[$entity->getEntityTypeId()][$entity->uuid()] = $this->serializer->serialize($entity, 'hal_json', ['json_encode_options' => JSON_PRETTY_PRINT]);
+    }
+    return $serialized_entities_per_type;
+  }
+
+  /**
+   * Returns all referenced entities of an entity.
+   *
+   * This method is also recursive to support usecases like a node -> media
+   * -> file.
+   *
+   * @param \Drupal\Core\Entity\ContentEntityInterface $entity
+   *   The entity.
+   * @param int $depth
+   *   Guard against infinite recursion.
+   *
+   * @return \Drupal\Core\Entity\EntityInterface[]
+   */
+  protected function getEntityReferencesRecursive(ContentEntityInterface $entity, $depth = 0) {
+    $entity_dependencies = $entity->referencedEntities();
+
+    foreach ($entity_dependencies as $id => $dependent_entity) {
+      // Config entities should not be exported but rather provided by default
+      // config.
+      if ($dependent_entity instanceof ConfigEntityInterface) {
+        unset($entity_dependencies[$id]);
+      }
+      $entity_dependencies = array_merge($entity_dependencies, $this->getEntityReferencesRecursive($dependent_entity, $depth + 1));
+    }
+
+    // Build in some support against infinite recursion.
+    if ($depth > 5) {
+      return $entity_dependencies;
+    }
+
+    return array_unique($entity_dependencies);
+  }
+
   /**
    * Utility to get a default content scanner
    *

src/DefaultContentManagerInterface.php

@@ -44,4 +44,17 @@ interface DefaultContentManagerInterface {
    */
   public function exportContent($entity_type_id, $entity_id);
 
+  /**
+   * Exports a single entity and all its referenced entity.
+   *
+   * @param string $entity_type_id
+   *   The entity type ID.
+   * @param $entity_id
+   *   The entity ID to export.
+   *
+   * @return string[][]
+   *   The serialized entities keyed by entity type and UUID.
+   */
+  public function exportContentWithReferences($entity_type_id, $entity_id);
+
 }