CODEWITHSUNDEEP
pythondjangodjango-rest-frameworkdjango-filterdrf-queryset
Abdul Rehman
Abdul Rehman

Reputation: 5664

Django Rest Framework filter on the base of JSONField nested objects

I'm working on a Project using Python(3), Django(1.11) and DRF in which I have to filter the data on the base of a json object field which is saved as JSONFIELD in db model.

Here's what I have tried:

# model.py

from django.db import models
import jsonfield

class MyModel(models.Model):
    id = models.CharField(primary_key=True, max_length=255)
    type = models.CharField(max_length=255)
    props = jsonfield.JSONField()
    repo = jsonfield.JSONField()
    created_at = models.DateTimeField()

# serializers.py

class MyModelSerializer(serializers.ModelSerializer):
    props = serializers.JSONField()
    repo = serializers.JSONField()

    class Meta:
        model = EventModel
        fields = "__all__"

# JSON object
{
  "id":4633249595,
  "type":"PushEvent",
  "props":{
    "id":4276597,
    "login":"iholloway",
    "avatar_url":"https://avatars.com/4276597"
  },
  "repo":{
    "id":269910,
    "name":"iholloway/aperiam-consectetur",
    "url":"https://github.com/iholloway/aperiam-consectetur"
  },
  "created_at":"2016-04-18 00:13:31"
}

# views.py

class PropsEvents(generics.RetrieveAPIView):
    serializer_class = MyModelSerializer

    def get_object(self):
        print(self.request.parser_context['kwargs']['id'])
        queryset = MyModel.objects.filter(data__props__id=self.request.parser_context['kwargs']['id'])
        obj = get_object_or_404(queryset)
       return obj

It should return the MyModel records by props ID and should be able to return the JSON array of all the MyModel objects where the props ID by the GET request at /mymodel/props/<ID>. If the requested props does not exist then HTTP response code should be 404, otherwise, the response code should be 200. The JSON array should be sorted in ascending order by MyModel ID.

When I sent a request to this view, it returns an error:

> django.core.exceptions.FieldError: Unsupported lookup 'id' for JSONField or join on the field not permitted.
> [18/Feb/2019 10:37:39] "GET /events/actors/2790311/ HTTP/1.1" 500 16210

So, how can I filter the objects based on the id of props?

Help me, please! Thanks in advance!

Upvotes: 0

Views: 2732

Answers (2)

mfrackowiak
mfrackowiak

Reputation: 1304

The feature your are looking for is possible, unfortunately it is not that straightforward. As far as I know it is not supported by the jsonfield package, but instead you would have to use Postgres as your database backend and use its internal JSONField. I think you can choose one of the following:

  • switch to django.contrib.postgres.fields.JSONField and use Postgres as your db backend in all enviroments (and then support such lookups)
  • make the data follow certain schema and change the JSONField to a separate model and table
  • use a hybrid storage solution with a dedicated solution for JSON documents
  • extract the fields you need to query against to your model - enabling the querying, but keeping the unstructured data in the JSONField.
class MyModel(models.Model):
    id = models.CharField(primary_key=True, max_length=255)
    type = models.CharField(max_length=255)
    props = jsonfield.JSONField()
    props_id = models.IntegerField(null=True)
    repo = jsonfield.JSONField()
    repo_id = models.IntegerField(null=True)
    created_at = models.DateTimeField()

And then set the id values manually or in the save() of the model:

def save(self, *args, **kwargs):
    self.repo_id = self.repo.get("id")
    self.props_id = self.props.get("id")
    return super().save(*args, **kwargs)

Upvotes: 3

Andrei Berenda
Andrei Berenda

Reputation: 1986

You should use 

from django.contrib.postgres.fields import JSONField

Instead of 

import jsonfield

And after that I think everything should work correctly

Upvotes: 0

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