Nested serializers only work with Django Model objects

While DRF works perfectly fine with simple non-model instances, DJA crashes and can’t be made to work correctly.

For example, this code works fine with DRF:

import random
from rest_framework.response import Response
from rest_framework.views import APIView
from rest_framework_json_api import serializers
from rest_framework_json_api.renderers import JSONRenderer as jsonapi_renderer


class Post(object):
    def __init__(self, message):
        super(Post, self).__init__()
        self.pk = 'tmp-%s' % random.randint(1, 2**20)  # Added to support json API referencing
        self.message = message


class User(object):
    def __init__(self, name, posts):
        super(User, self).__init__()
        self.pk = 'tmp-%s' % random.randint(1, 2**20)  # Added to support json API referencing
        self.name = name
        self.posts = posts


class PostSerializer(serializers.Serializer):
    message = serializers.CharField(max_length=200)


class UserSerializer(serializers.Serializer):
    name = serializers.CharField(max_length=200)
    posts = PostSerializer(many=True, read_only=True)


class UserView(APIView):
    resource_name = 'users'
    renderer_classes = (jsonapi_renderer,)  # ! Uncommenting this causes failure !

    def get(self, request, format=None):
        p1 = Post("First message")
        p2 = Post("Second message")
        user = User('Bob', [p1, p2])
        s = UserSerializer(user)
        return Response(s.data)

However, after uncommenting the line that specifies the JSON API renderer class to be used, the view crashes with:

'NoneType' object has no attribute 'Meta'

If DJA does not support Model-less references, it could at least be clearly stated in the documentation, mentioning also some workarounds if such exist. Though, I have not found any way to make this working yet.

[knaperek]

@adaptivdesign Thanks for such a prompt fix, I confirm that it no longer crashes.

However, I’m still missing the included top level key (with its data). Is this a missing feature in general, or is it pertinent to this Model-less setup? UPDATE: OK, included works when added as a query param inside the request. Would be nice to have the ability to set the default included types though.

Anyway, many thanks for help and quick fixing! You guys rock 👍

This is my output currently:

{
  "data": {
    "type": "users",
    "id": "tmp-953157",
    "attributes": {
      "name": "Bob"
    },
    "relationships": {
      "posts": {
        "data": [
          {
            "type": "post",
            "id": "tmp-545551"
          },
          {
            "type": "post",
            "id": "tmp-612679"
          }
        ]
      }
    }
  }
}

UPDATE 2: I have created PR #250 that implements this new option to specify resources to be included by default.

[rmmr]

Just came across the same issue. I will fix this in the coming hours. Pull request incoming.