Add a 'Pass Through URI' Data Converter to JSON-LD: Issue-1581

src/EntityReferenceConverter.php

@@ -0,0 +1,33 @@
+<?php
+
+namespace Drupal\jsonld;
+
+/**
+ * Converts EntityReferenceField targets.
+ */
+class EntityReferenceConverter {
+
+  /**
+   * Swaps out an Entity's URI with the value in a field.
+   *
+   * @param array|\Drupal\Core\Entity\EntityInterface $target
+   *   Either the target of the entity reference field being converted
+   *   (as the JSON-LD module does) or an array with 'target_id'
+   *   (as the RDF module does).
+   * @param array $arguments
+   *   An array of arguments defined in the mapping.
+   *   Expected keys are:
+   *     - link_field: The field used to store the URI we will use.
+   *
+   * @return mixed
+   *   Either the replaced URI string OR the targeted entity if no URI.
+   */
+  public static function linkFieldPassthrough($target, array $arguments) {
+    if (is_a($target, 'Drupal\Core\Entity\FieldableEntityInterface') && !empty($target->get($arguments['link_field'])->uri)) {
+      return $target->get($arguments['link_field'])->uri;
+    }
+    // We don't have a value to pass, so don't bother converting.
+    return $target;
+  }
+
+}

src/Normalizer/EntityReferenceItemNormalizer.php

@@ -76,9 +76,9 @@ public function normalize($field_item, $format = NULL, array $context = []) {
     $context['included_fields'] = ['uuid'];
     $context['needs_jsonldcontext'] = FALSE;
     $context['embedded'] = TRUE;
-    // Normalize the target entity.
-    // This will call \Drupal\jsonld\Normalizer\ContentEntityNormalizer.
-    $embedded = $this->serializer->normalize($target_entity, $format, $context);
+
+    // The normalized object we will collect entries into.
+    $normalized_in_context = [];
 
     if (isset($context['current_entity_rdf_mapping'])) {
       $values_clean = [];
@@ -93,25 +93,38 @@ public function normalize($field_item, $format = NULL, array $context = []) {
       $field_keys = isset($field_mappings['properties']) ?
             $field_mappings['properties'] :
             [$field_item->getParent()->getName()];
-      if (!empty($field_mappings['datatype'])) {
-        $values_clean['@type'] = $field_mappings['datatype'];
-      }
 
       // Value in this case is the target entity, so if a callback exists
-      // it should work against that?
+      // it should work against that.
       if (!empty($field_mappings['datatype_callback'])) {
         $callback = $field_mappings['datatype_callback']['callable'];
         $arguments = isset($field_mappings['datatype_callback']['arguments']) ? $field_mappings['datatype_callback']['arguments'] : NULL;
-        $values_clean['@value'] = call_user_func($callback, $target_entity, $arguments);
+        $transformed_value = call_user_func($callback, $target_entity, $arguments);
+        // If the config says it is an @id, we'll save it as an @id.
+        if (!empty($field_mappings['datatype']) && $field_mappings['datatype'] == '@id') {
+          $values_clean['@id'] = $transformed_value;
+          $values_clean['@type'] = '@id';
+        }
+        // Either we transformed it into another fieldable entity, or got the
+        // same one back. We will process the fieldable entity later on.
+        elseif ($transformed_value instanceof FieldableEntityInterface) {
+          $target_entity = $transformed_value;
+        }
+        // Save anything else as a value.
+        else {
+          $values_clean['@value'] = $transformed_value;
+        }
       }
-      // Since getting the to embed entity URL here could be a little bit
-      // expensive and would require an helper method
-      // i could just borrow it from the $embed result.
-      $values_clean['@id'] = key($embedded['@graph']);
-      // Because having a @type for a reference causes problems, we strip that.
-      // This could be removed using headers in future.
-      if (isset($values_clean['@type'])) {
-        unset($values_clean['@type']);
+      // Time to process the fieldable entity if we don't have
+      // an '@id' or '@value'.
+      if (empty($values_clean['@id']) && empty($values_clean['@value'])) {
+        // Normalize the target entity.
+        // This will call \Drupal\jsonld\Normalizer\ContentEntityNormalizer.
+        $normalized_in_context = $this->serializer->normalize($target_entity, $format, $context);
+        // Since getting the to embed entity URL here could be a little bit
+        // expensive and would require an helper method
+        // i could just borrow it from above.
+        $values_clean['@id'] = key($normalized_in_context['@graph']);
       }
 
       // The returned structure will be recursively merged into the normalized
@@ -130,7 +143,7 @@ public function normalize($field_item, $format = NULL, array $context = []) {
 
     }
 
-    $normalized_in_context = array_merge_recursive($embedded, ['@graph' => [$context['current_entity_id'] => $normalized_prop]]);
+    $normalized_in_context = array_merge_recursive($normalized_in_context, ['@graph' => [$context['current_entity_id'] => $normalized_prop]]);
 
     return $normalized_in_context;
   }

tests/src/Functional/JsonldContextGeneratorTest.php

@@ -27,6 +27,11 @@ class JsonldContextGeneratorTest extends BrowserTestBase {
     'jsonld',
   ];
 
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
   /**
    * Initial setup tasks that for every method method.
    */

tests/src/Kernel/JsonldKernelTestBase.php

@@ -174,7 +174,7 @@ protected function setUp() {
     ])->save();
 
     $entity_manager = \Drupal::service('entity_type.manager');
-    $link_manager = \Drupal::service('rest.link_manager');
+    $link_manager = \Drupal::service('hal.link_manager');
     $uuid_resolver = \Drupal::service('serializer.entity_resolver.uuid');
     $chain_resolver = new ChainEntityResolver([$uuid_resolver, new TargetIdResolver()]);