GraphQL: add "id" to attributes if "_id" is requested (fixes #2194) (#2195)

* GraphQL: add "id" to attributes if "_id" is requested

Fixes #2194.

* Fix all resolvers. Review.

* Wording

* Typo

Author: dunglas

features/graphql/query.feature

@@ -124,6 +124,20 @@ Feature: GraphQL query support
     And the header "Content-Type" should be equal to "application/json"
     And the JSON node "data.dummyGroup.foo" should be equal to "Foo #1"
 
+  Scenario: Fetch only the internal id
+    When I send the following GraphQL request:
+    """
+    {
+      dummy(id: "/dummies/1") {
+        _id
+      }
+    }
+    """
+    Then the response status code should be 200
+    And the response should be in JSON
+    And the header "Content-Type" should be equal to "application/json"
+    And the JSON node "data.dummy._id" should be equal to "1"
+
   @dropSchema
   Scenario: Retrieve an nonexistent item through a GraphQL query
     When I send the following GraphQL request:

src/GraphQl/Resolver/Factory/CollectionResolverFactory.php

@@ -18,6 +18,7 @@
 use ApiPlatform\Core\DataProvider\PaginatorInterface;
 use ApiPlatform\Core\DataProvider\SubresourceDataProviderInterface;
 use ApiPlatform\Core\Exception\ResourceClassNotSupportedException;
+use ApiPlatform\Core\GraphQl\Resolver\FieldsToAttributesTrait;
 use ApiPlatform\Core\GraphQl\Resolver\ResourceAccessCheckerTrait;
 use ApiPlatform\Core\GraphQl\Serializer\ItemNormalizer;
 use ApiPlatform\Core\Metadata\Resource\Factory\ResourceMetadataFactoryInterface;
@@ -37,6 +38,7 @@
  */
 final class CollectionResolverFactory implements ResolverFactoryInterface
 {
+    use FieldsToAttributesTrait;
     use ResourceAccessCheckerTrait;
 
     private $collectionDataProvider;
@@ -125,16 +127,6 @@ public function __invoke(string $resourceClass = null, string $rootClass = null,
         };
     }
 
-    private function fieldsToAttributes(ResolveInfo $info): array
-    {
-        $fields = $info->getFieldSelection(PHP_INT_MAX);
-        if (isset($fields['edges']['node'])) {
-            $fields = $fields['edges']['node'];
-        }
-
-        return $fields;
-    }
-
     /**
      * @throws ResourceClassNotSupportedException
      *

src/GraphQl/Resolver/Factory/ItemMutationResolverFactory.php

@@ -17,6 +17,7 @@
 use ApiPlatform\Core\DataPersister\DataPersisterInterface;
 use ApiPlatform\Core\Exception\InvalidArgumentException;
 use ApiPlatform\Core\Exception\ItemNotFoundException;
+use ApiPlatform\Core\GraphQl\Resolver\FieldsToAttributesTrait;
 use ApiPlatform\Core\GraphQl\Resolver\ResourceAccessCheckerTrait;
 use ApiPlatform\Core\GraphQl\Serializer\ItemNormalizer;
 use ApiPlatform\Core\Metadata\Resource\Factory\ResourceMetadataFactoryInterface;
@@ -38,6 +39,7 @@
  */
 final class ItemMutationResolverFactory implements ResolverFactoryInterface
 {
+    use FieldsToAttributesTrait;
     use ResourceAccessCheckerTrait;
 
     private $iriConverter;
@@ -73,7 +75,7 @@ public function __invoke(string $resourceClass = null, string $rootClass = null,
 
             $resourceMetadata = $this->resourceMetadataFactory->create($resourceClass);
             $normalizationContext = $resourceMetadata->getGraphqlAttribute($operationName ?? '', 'normalization_context', [], true);
-            $normalizationContext['attributes'] = $info->getFieldSelection(PHP_INT_MAX);
+            $normalizationContext['attributes'] = $this->fieldsToAttributes($info);
 
             if (isset($args['input']['id'])) {
                 try {

src/GraphQl/Resolver/FieldsToAttributesTrait.php

@@ -0,0 +1,51 @@
+<?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\Core\GraphQl\Resolver;
+
+use GraphQL\Type\Definition\ResolveInfo;
+
+/**
+ * Transforms the passed GraphQL fields to the list of attributes to serialize.
+ *
+ * @author Kévin Dunglas <dunglas@gmail.com>
+ */
+trait FieldsToAttributesTrait
+{
+    /**
+     * Retrieves fields, recursively replaces the "_id" key (the raw id) by "id" (the name of the property expected by the Serializer) and flattens edge and node structures (pagination).
+     */
+    private function fieldsToAttributes(ResolveInfo $info): array
+    {
+        $fields = $info->getFieldSelection(PHP_INT_MAX);
+        if (isset($fields['edges']['node'])) {
+            $fields = $fields['edges']['node'];
+        }
+
+        return $this->replaceIdKeys($fields);
+    }
+
+    private function replaceIdKeys(array $fields): array
+    {
+        foreach ($fields as $key => $value) {
+            if ('_id' === $key) {
+                $fields['id'] = $fields['_id'];
+                unset($fields['_id']);
+            } elseif (\is_array($fields[$key])) {
+                $fields[$key] = $this->replaceIdKeys($fields[$key]);
+            }
+        }
+
+        return $fields;
+    }
+}

src/GraphQl/Resolver/ItemResolver.php

@@ -33,6 +33,7 @@
 final class ItemResolver
 {
     use ClassInfoTrait;
+    use FieldsToAttributesTrait;
     use ResourceAccessCheckerTrait;
 
     private $iriConverter;
@@ -59,7 +60,7 @@ public function __invoke($source, $args, $context, ResolveInfo $info)
             return null;
         }
 
-        $baseNormalizationContext = ['attributes' => $info->getFieldSelection(PHP_INT_MAX)];
+        $baseNormalizationContext = ['attributes' => $this->fieldsToAttributes($info)];
         try {
             $item = $this->iriConverter->getItemFromIri($args['id'], $baseNormalizationContext);
         } catch (ItemNotFoundException $e) {