Fails for recursive fields.

[noodlebreak]

This is my serializer:

class CategoryRecursiveSerializer(DynamicFieldsMixin, serializers.ModelSerializer):
    children = serializers.ListField(read_only=True, source='get_children', child=RecursiveField())
    value = serializers.CharField(source='name', read_only=True)  # hack requested by frontend
    parent = fields.CategoryField(queryset=models.Category.objects.all(),
                                             required=False, allow_null=True)

This is my request:

http://api.mlocal.com/api/v1/categories/?fields=id,value,children

This is my response:

{
  "count": 20,
  "next": null,
  "previous": null,
  "results": [
    {
      "id": "5914220d-c455-45ff-a135-e9ac7f307dae",
      "value": "Fruits & Vegetables",
      "children": [
        {
          "id": "7426afb3-b2b6-4f74-8a25-6e5e5865fb4f",
          "name": "Fresh Vegetables",
          "value": "Fresh Vegetables",
          "image": null,
          "is_featured": false,
          "children": [],
          "parent": {
            "id": "5914220d-c455-45ff-a135-e9ac7f307dae",
            "name": "Fruits & Vegetables",
            "image": "http://api.mlocal.com/categories/35629/fruits-vegetables-41698-1523944087.png",
            "is_featured": true,
            "parent": null,
            "created": "2018-07-17T09:27:42.920241Z"
          },
          "created": "2018-07-17T09:28:32.731214Z"
        }
      ],
      "image": "http://api.mlocal.com/categories/35629/fruits-vegetables-41698-1523944087.png"
    }
  ]
}

The parent field comes in nested children, except for the root objects in which only the fields that I mentioned come.

[dbrgn]

This is probably a duplicate of #15 (or at least closely related). Possibly drf-flex-fields solves your use case?

It's nontrivial to solve this for the general case and since I don't have much time to maintain this library I want to intentionally keep it simple (unless @jtrain thinks this is worth pursueing or unless a PR is submitted with a very simple implementation and tests). So currently recursive filtering is out of scope.

[jtrain]

I agree with @dbrgn here. Applying the filtering to child serializers could spiral our complexity.

One way I'd solve this is to use a separate serializer for the children that doesn't have the fields you don't want. You needn't even use a ModelSerializer base, just a plain serializer.Serializer for a nice performance boost too.