support for DictField child type (#142) and models.JSONField (Django>…

…=3.1)

docs/customization.rst

@@ -37,7 +37,7 @@ discovered in the introspection.
         def retrieve(self, request, *args, **kwargs)
             # your code
 
-.. note:: For simple responses, you might go through the hassle of writing an explicit serializer class.
+.. note:: For simple responses, you might not go through the hassle of writing an explicit serializer class.
   In those cases, you can simply specify the request/response with a call to
   :py:func:`inline_serializer <drf_spectacular.utils.inline_serializer>`.
   This lets you conveniently define the endpoint's schema inline without actually writing a serializer class.

drf_spectacular/openapi.py

@@ -374,6 +374,9 @@ def _map_model_field(self, model_field, direction):
             return self._map_serializer_field(field, direction)
         elif isinstance(model_field, models.ForeignKey):
             return self._map_model_field(model_field.target_field, direction)
+        elif hasattr(models, 'JSONField') and isinstance(model_field, models.JSONField):
+            # fix for DRF==3.11 with django>=3.1 as it is not yet represented in the field_mapping
+            return build_basic_type(OpenApiTypes.OBJECT)
         elif hasattr(models, model_field.get_internal_type()):
             # be graceful when the model field is not explicitly mapped to a serializer
             internal_type = getattr(models, model_field.get_internal_type())
@@ -553,9 +556,15 @@ def _map_serializer_field(self, field, direction):
         if anyisinstance(field, [serializers.BooleanField, serializers.NullBooleanField]):
             return append_meta(build_basic_type(OpenApiTypes.BOOL), meta)
 
-        if anyisinstance(field, [serializers.JSONField, serializers.DictField, serializers.HStoreField]):
+        if isinstance(field, serializers.JSONField):
             return append_meta(build_basic_type(OpenApiTypes.OBJECT), meta)
 
+        if anyisinstance(field, [serializers.DictField, serializers.HStoreField]):
+            content = build_basic_type(OpenApiTypes.OBJECT)
+            if not isinstance(field.child, _UnvalidatedField):
+                content['additionalProperties'] = self._map_serializer_field(field.child, direction)
+            return append_meta(content, meta)
+
         if isinstance(field, serializers.CharField):
             return append_meta(build_basic_type(OpenApiTypes.STR), meta)
 

tests/test_fields.py

@@ -4,6 +4,7 @@
 from decimal import Decimal
 
 import pytest
+from django import __version__ as DJANGO_VERSION
 from django.core.files.base import ContentFile
 from django.core.files.storage import FileSystemStorage
 from django.db import models
@@ -61,6 +62,13 @@ class AllFields(models.Model):
     field_regex = models.CharField(max_length=50)
     field_bool_override = models.BooleanField()
 
+    if DJANGO_VERSION >= '3.1':
+        field_json = models.JSONField()
+    else:
+        @property
+        def field_json(self):
+            return {'A': 1, 'B': 2}
+
     @property
     def field_model_property_float(self) -> float:
         return 1.337
@@ -128,6 +136,15 @@ def get_field_method_object(self, obj) -> dict:
 
     field_model_property_float = serializers.ReadOnlyField()
 
+    field_dict_int = serializers.DictField(
+        child=serializers.IntegerField(),
+        source='field_json',
+    )
+
+    # there is a JSON model field for django>=3.1 that would be placed automatically. for <=3.1 we
+    # need to set the field explicitly. defined here for both cases to have consistent ordering.
+    field_json = serializers.JSONField()
+
     class Meta:
         fields = '__all__'
         model = AllFields
@@ -213,6 +230,8 @@ def test_model_setup_is_valid():
         field_regex='12345asdfg-a',
         field_bool_override=True,
     )
+    if DJANGO_VERSION >= '3.1':
+        m.field_json = {'A': 1, 'B': 2}
     m.field_file.save('hello.txt', ContentFile("hello world"), save=True)
     m.save()
     m.field_m2m.add(aux)

tests/test_fields.yml

@@ -158,6 +158,13 @@ components:
           type: number
           format: float
           readOnly: true
+        field_dict_int:
+          type: object
+          additionalProperties:
+            type: integer
+        field_json:
+          type: object
+          additionalProperties: {}
         field_int:
           type: integer
         field_float:
@@ -246,6 +253,7 @@ components:
       - field_datetime
       - field_decimal
       - field_decimal_uncoerced
+      - field_dict_int
       - field_duration
       - field_email
       - field_file
@@ -256,6 +264,7 @@ components:
       - field_int
       - field_ip
       - field_ip_generic
+      - field_json
       - field_list
       - field_m2m
       - field_method_float