Extend DjangoListField to use model queryset if none defined (#732)

* Fix model property

* Only allow DjangoObjectTypes to DjangoListField

* Resolve model queryset by default

* Add some more tests to check behaviour

graphene_django/fields.py

@@ -1,13 +1,12 @@
 from functools import partial
 
 from django.db.models.query import QuerySet
-from graphene import NonNull
-
+from graphql_relay.connection.arrayconnection import connection_from_list_slice
 from promise import Promise
 
-from graphene.types import Field, List
+from graphene import NonNull
 from graphene.relay import ConnectionField, PageInfo
-from graphql_relay.connection.arrayconnection import connection_from_list_slice
+from graphene.types import Field, List
 
 from .settings import graphene_settings
 from .utils import maybe_queryset
@@ -15,19 +14,43 @@ from .utils import maybe_queryset
 
 class DjangoListField(Field):
     def __init__(self, _type, *args, **kwargs):
+        from .types import DjangoObjectType
+
+        if isinstance(_type, NonNull):
+            _type = _type.of_type
+
+        assert issubclass(
+            _type, DjangoObjectType
+        ), "DjangoListField only accepts DjangoObjectType types"
+
         # Django would never return a Set of None  vvvvvvv
         super(DjangoListField, self).__init__(List(NonNull(_type)), *args, **kwargs)
 
     @property
     def model(self):
-        return self.type.of_type._meta.node._meta.model
+        _type = self.type.of_type
+        if isinstance(_type, NonNull):
+            _type = _type.of_type
+        return _type._meta.model
 
     @staticmethod
-    def list_resolver(resolver, root, info, **args):
-        return maybe_queryset(resolver(root, info, **args))
+    def list_resolver(django_object_type, resolver, root, info, **args):
+        queryset = maybe_queryset(resolver(root, info, **args))
+        if queryset is None:
+            # Default to Django Model queryset
+            # N.B. This happens if DjangoListField is used in the top level Query object
+            model = django_object_type._meta.model
+            queryset = maybe_queryset(
+                django_object_type.get_queryset(model.objects, info)
+            )
+        return queryset
 
     def get_resolver(self, parent_resolver):
-        return partial(self.list_resolver, parent_resolver)
+        _type = self.type
+        if isinstance(_type, NonNull):
+            _type = _type.of_type
+        django_object_type = _type.of_type.of_type
+        return partial(self.list_resolver, django_object_type, parent_resolver)
 
 
 class DjangoConnectionField(ConnectionField):

graphene_django/tests/test_fields.py

@@ -0,0 +1,199 @@
+import datetime
+
+import pytest
+
+from graphene import List, NonNull, ObjectType, Schema, String
+
+from ..fields import DjangoListField
+from ..types import DjangoObjectType
+from .models import Article as ArticleModel
+from .models import Reporter as ReporterModel
+
+
+@pytest.mark.django_db
+class TestDjangoListField:
+    def test_only_django_object_types(self):
+        class TestType(ObjectType):
+            foo = String()
+
+        with pytest.raises(AssertionError):
+            list_field = DjangoListField(TestType)
+
+    def test_non_null_type(self):
+        class Reporter(DjangoObjectType):
+            class Meta:
+                model = ReporterModel
+                fields = ("first_name",)
+
+        list_field = DjangoListField(NonNull(Reporter))
+
+        assert isinstance(list_field.type, List)
+        assert isinstance(list_field.type.of_type, NonNull)
+        assert list_field.type.of_type.of_type is Reporter
+
+    def test_get_django_model(self):
+        class Reporter(DjangoObjectType):
+            class Meta:
+                model = ReporterModel
+                fields = ("first_name",)
+
+        list_field = DjangoListField(Reporter)
+        assert list_field.model is ReporterModel
+
+    def test_list_field_default_queryset(self):
+        class Reporter(DjangoObjectType):
+            class Meta:
+                model = ReporterModel
+                fields = ("first_name",)
+
+        class Query(ObjectType):
+            reporters = DjangoListField(Reporter)
+
+        schema = Schema(query=Query)
+
+        query = """
+            query {
+                reporters {
+                    firstName
+                }
+            }
+        """
+
+        ReporterModel.objects.create(first_name="Tara", last_name="West")
+        ReporterModel.objects.create(first_name="Debra", last_name="Payne")
+
+        result = schema.execute(query)
+
+        assert not result.errors
+        assert result.data == {
+            "reporters": [{"firstName": "Tara"}, {"firstName": "Debra"}]
+        }
+
+    def test_override_resolver(self):
+        class Reporter(DjangoObjectType):
+            class Meta:
+                model = ReporterModel
+                fields = ("first_name",)
+
+        class Query(ObjectType):
+            reporters = DjangoListField(Reporter)
+
+            def resolve_reporters(_, info):
+                return ReporterModel.objects.filter(first_name="Tara")
+
+        schema = Schema(query=Query)
+
+        query = """
+            query {
+                reporters {
+                    firstName
+                }
+            }
+        """
+
+        ReporterModel.objects.create(first_name="Tara", last_name="West")
+        ReporterModel.objects.create(first_name="Debra", last_name="Payne")
+
+        result = schema.execute(query)
+
+        assert not result.errors
+        assert result.data == {"reporters": [{"firstName": "Tara"}]}
+
+    def test_nested_list_field(self):
+        class Article(DjangoObjectType):
+            class Meta:
+                model = ArticleModel
+                fields = ("headline",)
+
+        class Reporter(DjangoObjectType):
+            class Meta:
+                model = ReporterModel
+                fields = ("first_name", "articles")
+
+        class Query(ObjectType):
+            reporters = DjangoListField(Reporter)
+
+        schema = Schema(query=Query)
+
+        query = """
+            query {
+                reporters {
+                    firstName
+                    articles {
+                        headline
+                    }
+                }
+            }
+        """
+
+        r1 = ReporterModel.objects.create(first_name="Tara", last_name="West")
+        ReporterModel.objects.create(first_name="Debra", last_name="Payne")
+
+        ArticleModel.objects.create(
+            headline="Amazing news",
+            reporter=r1,
+            pub_date=datetime.date.today(),
+            pub_date_time=datetime.datetime.now(),
+            editor=r1,
+        )
+
+        result = schema.execute(query)
+
+        assert not result.errors
+        assert result.data == {
+            "reporters": [
+                {"firstName": "Tara", "articles": [{"headline": "Amazing news"}]},
+                {"firstName": "Debra", "articles": []},
+            ]
+        }
+
+    def test_override_resolver_nested_list_field(self):
+        class Article(DjangoObjectType):
+            class Meta:
+                model = ArticleModel
+                fields = ("headline",)
+
+        class Reporter(DjangoObjectType):
+            class Meta:
+                model = ReporterModel
+                fields = ("first_name", "articles")
+
+            def resolve_reporters(reporter, info):
+                return reporter.articles.all()
+
+        class Query(ObjectType):
+            reporters = DjangoListField(Reporter)
+
+        schema = Schema(query=Query)
+
+        query = """
+            query {
+                reporters {
+                    firstName
+                    articles {
+                        headline
+                    }
+                }
+            }
+        """
+
+        r1 = ReporterModel.objects.create(first_name="Tara", last_name="West")
+        ReporterModel.objects.create(first_name="Debra", last_name="Payne")
+
+        ArticleModel.objects.create(
+            headline="Amazing news",
+            reporter=r1,
+            pub_date=datetime.date.today(),
+            pub_date_time=datetime.datetime.now(),
+            editor=r1,
+        )
+
+        result = schema.execute(query)
+
+        assert not result.errors
+        assert result.data == {
+            "reporters": [
+                {"firstName": "Tara", "articles": [{"headline": "Amazing news"}]},
+                {"firstName": "Debra", "articles": []},
+            ]
+        }