Merge pull request #14 from dbrgn/nested_serializers

Do not apply filter to nested serializers

Author: dbrgn

drf_dynamic_fields/__init__.py

@@ -15,14 +15,22 @@ def fields(self):
         """
         Filters the fields according to the `fields` query parameter.
 
-        a blank `fields` parameter (?fields) will remove all fields.
-        not passing `fields` will pass all fields
-        individual fields are comma separated (?fields=id,name,url,email)
+        A blank `fields` parameter (?fields) will remove all fields. Not
+        passing `fields` will pass all fields individual fields are comma
+        separated (?fields=id,name,url,email).
+
         """
         fields = super(DynamicFieldsMixin, self).fields
 
         if not hasattr(self, '_context'):
-            # we are being called before a request cycle.
+            # We are being called before a request cycle
+            return fields
+
+        # Only filter if this is the root serializer, or if the parent is the
+        # root serializer with many=True
+        is_root = self.root == self
+        parent_is_list_root = self.parent == self.root and getattr(self.parent, 'many', False)
+        if not (is_root or parent_is_list_root):
             return fields
 
         try:

tests/serializers.py

@@ -31,7 +31,7 @@ def get_request_info(self, teacher):
         )
 
 
-class SchoolSerializer(serializers.ModelSerializer):
+class SchoolSerializer(DynamicFieldsMixin, serializers.ModelSerializer):
     """
     Interesting enough serializer because the TeacherSerializer
     will use ListSerializer due to the `many=True`

tests/test_mixins.py

@@ -141,9 +141,8 @@ def test_as_nested_serializer(self):
         """
         Nested serializers are not filtered.
         """
-
         rf = RequestFactory()
-        request = rf.get('/api/v1/schools/1/')
+        request = rf.get('/api/v1/schools/1/?fields=teachers')
 
         school = School.objects.create()
         teachers = [
@@ -168,6 +167,5 @@ def test_as_nested_serializer(self):
                         ('request_info', request_info.format(teachers[1].id))
                     ])
                 ],
-                'id': school.id
             }
         )