refactor: add get_id support for resource identifier

Author: axieum

rest_framework_json_api/renderers.py

@@ -443,12 +443,9 @@ def build_json_resource_obj(
         # Determine type from the instance if the underlying model is polymorphic
         if force_type_resolution:
             resource_name = utils.get_resource_type_from_instance(resource_instance)
-        resource_id = utils.get_resource_id_from_instance(
-            resource
-        ) or utils.get_resource_id_from_instance(resource_instance)
         resource_data = {
             "type": resource_name,
-            "id": force_str(resource_id) if resource_id is not None else None,
+            "id": utils.get_resource_id_from_instance(resource_instance, resource),
             "attributes": cls.extract_attributes(fields, resource),
         }
         relationships = cls.extract_relationships(fields, resource, resource_instance)

rest_framework_json_api/utils.py

@@ -304,16 +304,18 @@ def get_resource_type_from_serializer(serializer):
     )
 
 
-def get_resource_id_from_instance(instance):
+def get_resource_id_from_instance(resource_instance, resource):
     """Returns the resource identifier for a given instance (`id` takes priority over `pk`)."""
-    if not instance:
-        return None
-    elif hasattr(instance, "id"):
-        return instance.id
-    elif hasattr(instance, "pk"):
-        return instance.pk
-    elif isinstance(instance, dict):
-        return instance.get("id", instance.get("pk", None))
+    if resource and "id" in resource:
+        return resource["id"] and encoding.force_str(resource["id"]) or None
+    if resource_instance:
+        if hasattr(resource_instance, "get_id") and callable(resource_instance.get_id):
+            return encoding.force_str(resource_instance.get_id())
+        return (
+            hasattr(resource_instance, "pk")
+            and encoding.force_str(resource_instance.pk)
+            or None
+        )
     return None
 
 

tests/test_utils.py

@@ -406,20 +406,23 @@ class ObjectWithPkAndId(ObjectWithId, ObjectWithPk):
 
 
 @pytest.mark.parametrize(
-    "instance, expected",
+    "resource_instance, resource, expected",
     [
-        (None, None),
-        (BasicModel(id=5), 5),
-        (ObjectWithId(), 9),
-        (ObjectWithPk(), 7),
-        (ObjectWithPkAndId(), 9),
-        ({"id": 11}, 11),
-        ({"pk": 13}, 13),
-        ({"pk": 11, "id": 13}, 13),
+        (None, None, None),
+        (object(), {}, None),
+        (BasicModel(id=5), None, "5"),
+        (ObjectWithId(), {}, "9"),
+        (ObjectWithPk(), None, "7"),
+        (ObjectWithPkAndId(), None, "9"),
+        (None, {"id": 11}, "11"),
+        (object(), {"pk": 11}, None),
+        (ObjectWithId(), {"id": 11}, "11"),
+        (ObjectWithPk(), {"pk": 13}, "7"),
+        (ObjectWithPkAndId(), {"id": 12, "pk": 13}, "12"),
     ],
 )
-def test_get_resource_id_from_instance(instance, expected):
-    assert get_resource_id_from_instance(instance) == expected
+def test_get_resource_id_from_instance(resource_instance, resource, expected):
+    assert get_resource_id_from_instance(resource_instance, resource) == expected
 
 
 @pytest.mark.parametrize(

tests/test_views.py

@@ -205,6 +205,28 @@ def test_post_with_missing_id(self, client):
             }
         }
 
+    @pytest.mark.urls(__name__)
+    def test_custom_id(self, client):
+        data = {
+            "data": {
+                "id": 2_193_102,
+                "type": "custom",
+                "attributes": {"body": "hello"},
+            }
+        }
+
+        url = reverse("custom-id")
+
+        response = client.patch(url, data=data)
+        assert response.status_code == status.HTTP_200_OK
+        assert response.json() == {
+            "data": {
+                "type": "custom",
+                "id": "2176ce",  # get_id() -> hex
+                "attributes": {"body": "hello"},
+            }
+        }
+
 
 # Routing setup
 
@@ -224,6 +246,14 @@ class CustomModelSerializer(serializers.Serializer):
     id = serializers.IntegerField()
 
 
+class CustomIdModelSerializer(serializers.Serializer):
+    body = serializers.CharField()
+    id = serializers.IntegerField()
+
+    def get_id(self):
+        return hex(self.validated_data["id"])[2:]
+
+
 class CustomAPIView(APIView):
     parser_classes = [JSONParser]
     renderer_classes = [JSONRenderer]
@@ -238,10 +268,21 @@ def post(self, request, *args, **kwargs):
         return Response(status=status.HTTP_200_OK, data=serializer.data)
 
 
+class CustomIdAPIView(APIView):
+    parser_classes = [JSONParser]
+    renderer_classes = [JSONRenderer]
+    resource_name = "custom"
+
+    def patch(self, request, *args, **kwargs):
+        serializer = CustomIdModelSerializer(CustomModel(request.data))
+        return Response(status=status.HTTP_200_OK, data=serializer.data)
+
+
 router = SimpleRouter()
 router.register(r"basic_models", BasicModelViewSet, basename="basic-model")
 
 urlpatterns = [
     path("custom", CustomAPIView.as_view(), name="custom"),
+    path("custom-id", CustomIdAPIView.as_view(), name="custom-id"),
 ]
 urlpatterns += router.urls