Add DjangoFormInputObjectType to forms/types

InputObjectType derived class which gets fields from django form.
Type of fields with choices (converted to enum) is set to custom scalar
type (using Meta.object_type) to dynamically convert enum values back.

graphene_django/forms/types.py

@@ -1 +1,120 @@
+import graphene
+
+from graphene import ID
+from graphene.types.inputobjecttype import InputObjectType
+from graphene.utils.str_converters import to_camel_case
+
+from .mutation import fields_for_form
 from ..types import ErrorType  # noqa Import ErrorType for backwards compatability
+from ..converter import BlankValueField
+
+
+class DjangoFormInputObjectType(InputObjectType):
+    @classmethod
+    def __init_subclass_with_meta__(
+        cls,
+        container=None,
+        _meta=None,
+        only_fields=(),
+        exclude_fields=(),
+        form_class=None,
+        object_type=None,
+        add_id_field_name=None,
+        add_id_field_type=None,
+        **options,
+    ):
+        """Retrieve fields from django form (Meta.form_class). Received
+        fields are set to cls (they will be converted to input fields
+        by InputObjectType). Type of fields with choices (converted
+        to enum) is set to custom scalar type (using Meta.object_type)
+        to dynamically convert enum values back.
+
+        class MyDjangoFormInput(DjangoFormInputObjectType):
+            # any other fields can be placed here and other inputobjectforms as well
+
+            class Meta:
+                form_class = MyDjangoModelForm
+                object_type = MyModelType
+
+        class SomeMutation(graphene.Mutation):
+            class Arguments:
+                data = MyDjangoFormInput(required=True)
+
+            @staticmethod
+            def mutate(_root, _info, data):
+                form_inst = MyDjangoModelForm(data=data)
+                if form_inst.is_valid():
+                    django_model_instance = form_inst.save(commit=False)
+                # ... etc ...
+        """
+
+        if not form_class:
+            raise Exception("form_class is required for DjangoFormInputObjectType")
+
+        form = form_class()
+        form_fields = fields_for_form(form, only_fields, exclude_fields)
+
+        for name, field in form_fields.items():
+            if (
+                object_type
+                and name in object_type._meta.fields
+                and isinstance(object_type._meta.fields[name], BlankValueField)
+            ):
+                # Field type BlankValueField here means that field
+                # with choises have been converted to enum
+                # (BlankValueField is using only for that task ?)
+                setattr(cls, name, cls.get_enum_cnv_cls_instance(name, object_type))
+            elif (
+                object_type
+                and name in object_type._meta.fields
+                and object_type._meta.convert_choices_to_enum is False
+                and form.fields[name].__class__.__name__ == "TypedChoiceField"
+            ):
+                # FIXME
+                # in case if convert_choices_to_enum is False
+                # form field class is converted to String but original
+                # model field type is needed here... (.converter.py bug?)
+                # This is temp workaround to get field type from ObjectType field
+                # TEST: test_enum_not_converted_and_field_type_as_in_model
+                setattr(cls, name, object_type._meta.fields[name].type())
+            else:
+                # set input field according to django form field
+                setattr(cls, name, field)
+
+        # explicitly adding id field (absent in django form fields)
+        # with name and type from Meta or 'id' with graphene.ID by default
+        if add_id_field_name:
+            setattr(cls, add_id_field_name, add_id_field_type or ID(required=False))
+        elif "id" not in exclude_fields:
+            cls.id = ID(required=False)
+
+        super(DjangoFormInputObjectType, cls).__init_subclass_with_meta__(
+            container=container, _meta=_meta, **options
+        )
+
+    @staticmethod
+    def get_enum_cnv_cls_instance(field_name, object_type):
+        """Saves args in context to convert enum values in
+        Dynamically created Scalar derived class
+        """
+
+        @staticmethod
+        def parse_value(value):
+            # field_name & object_type have been saved in context (closure)
+            field = object_type._meta.fields[field_name]
+            if isinstance(field.type, graphene.NonNull):
+                val_before_convert = field.type._of_type[value].value
+            else:
+                val_before_convert = field.type[value].value
+            return graphene.String.parse_value(val_before_convert)
+
+        cls_doc = "String scalar to convert choice value back from enum to original"
+        scalar_type = type(
+            (
+                f"{field_name[0].upper()}{to_camel_case(field_name[1:])}"
+                "EnumBackConvString"
+            ),
+            (graphene.String,),
+            {"parse_value": parse_value, "__doc__": cls_doc},
+        )
+        return scalar_type()

graphene_django/types.py

@@ -252,6 +252,7 @@ class DjangoObjectType(ObjectType):
         _meta.filterset_class = filterset_class
         _meta.fields = django_fields
         _meta.connection = connection
+        _meta.convert_choices_to_enum = convert_choices_to_enum
 
         super().__init_subclass_with_meta__(
             _meta=_meta, interfaces=interfaces, **options