Django Rest Framework: Dynamically return subset of fields

Question

Problem

As recommended in the blogpost Best Practices for Designing a Pragmatic RESTful API, I would like to add a fields query parameter to a Django R

Answer 1

If you want something flexible like GraphQL, you can use django-restql. It supports nested data (both flat and iterable).

Example

from rest_framework import serializers
from django.contrib.auth.models import User
from django_restql.mixins import DynamicFieldsMixin

class UserSerializer(DynamicFieldsMixin, serializers.ModelSerializer):
    class Meta:
        model = User
        fields = ('id', 'username', 'email', 'groups')

A regular request returns all fields.

GET /users

    [
      {
        "id": 1,
        "username": "yezyilomo",
        "email": "yezileliilomo@hotmail.com",
        "groups": [1,2]
      },
      ...
    ]

A request with the query parameter on the other hand returns only a subset of the fields:

GET /users/?query={id, username}

    [
      {
        "id": 1,
        "username": "yezyilomo"
      },
      ...
    ]

With django-restql you can access nested fields of any level. E.g

GET /users/?query={id, username, date_joined{year}}

    [
      {
        "id": 1,
        "username": "yezyilomo",
        "date_joined": {
            "year": 2018
        }
      },
      ...
    ]

For iterable nested fields, E.g groups on users.

GET /users/?query={id, username, groups{id, name}}

    [
      {
        "id": 1,
        "username": "yezyilomo",
        "groups": [
            {
                "id": 2,
                "name": "Auth_User"
            }
        ]
      },
      ...
    ]