django-restql 0.2.1

Dynamically select only a subset of fields per DRF resource(Support both flat and nested resources)

django-restql

django-restql is a python library which allows you to turn your API made with Django REST Framework(DRF) into a GraphQL like API. With this you will be able to

• Send a query to your API and get exactly what you need, nothing more and nothing less.

• Control the data you get, not the server.

• Get predictable results, since you control what you get from the server.

• Save the load of fetching unused data from the server.

Isn't it cool?.

django-restql works by selecting dynamically a subset of fields per DRF resource as specified by the request's query parameter.

Installing

pip install django-restql

Getting Started

Using django-restql is very simple, you just have to use the DynamicFieldsMixin when defining a View.

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

class UserViewSet(DynamicFieldsMixin, viewsets.ModelViewSet):
    queryset = User.objects.all().order_by('-date_joined')
    serializer_class = UserSerializer

A regular request returns all fields specified on DRF serializer, in fact django-restql doesn't handle this request at all:

GET /users

    [
      {
        "id": 1,
        "username": "yezyilomo",
        "email": "[e-mail]",
        "groups": [1,2]
      },
      ...
    ]

django-restql handle all GET requests with query parameter, this parameter is the one used to pass all fields to be included on a response. For example to select id and username fields from user model, send a request with a query parameter as shown below.

GET /users/?query=["id", "username"]

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

If a query contains nested field, django-restql will return its id or array of ids for the case of nested iterable field(one2many or many2many). For example on a request below location is a flat nested field(many2one) and groups is an iterable nested field(one2many or many2many).

GET /users/?query=["id", "username", "location", "groups"]

    [
      {
        "id": 1,
        "username": "yezyilomo",
        "location": 6,
        "groups": [1,2]
      },
      ...
    ]

django-restql support querying both flat and nested resources, so you can expand or query nested fields at any level as long as your field is defined as nested field on a serializer. For example you can query a country and region field from location.

GET /users/?query=["id", "username", {"location": ["country", "region"]}]

    [
      {
        "id": 1,
        "username": "yezyilomo",
        "location": {
            "contry": "Tanzania",
            "region": "Dar es salaam"
        }
      },
      ...
    ]

django-restql got your back on expanding or querying iterable nested fields too. For example if you want to expand groups field into id and name, here is how you would do it.

GET /users/?query=["id", "username", {"groups": [ "id", "name" ]}]

    [
      {
        "id": 1,
        "username": "yezyilomo",
        "groups": [
            {
                "id": 2,
                "name": "Auth_User"
            }
            {
                "id": 3,
                "name": "Admin_User"
            }
        ]
      },
      ...
    ]

Customizing django-restql

django-restql is very configurable, here is what you can customize

• Change the name of query parameter.

  If you don't want to use the name query as your parameter, you can inherit DynamicFieldsMixin and change it as shown below

  from django_restql.mixins import DynamicFieldsMixin
  
  class MyDynamicFieldMixin(DynamicFieldsMixin):
      query_param_name = "your_favourite_name"
  

  Now you can use this Mixin on your view and use the name your_favourite_name as your parameter. E.g

  GET /users/?your_favourite_name=["id", "username"]

• Customize how it filter fields to include in a response. You can do this by inheriting DynamicFieldsMixin and override list and retrieve methods as shown below.

  from django_restql.mixins import DynamicFieldsMixin
  
  class CustomDynamicFieldMixin(DynamicFieldsMixin):
      def list(self, request):
          # Your customization here
          return response
  
      def retrieve(self, request):
          # Your customization here
          return response
  

  Note: To be able to do this you must understand how django-restql is implemented, specifically DynamicFieldsMixin class, you can check it here. In fact this is how django-restql is implemented(overriding list and retrieve methods of a view, nothing more and nothing less).

Running Tests

python setup.py test

Credits

This implementation is based on dictfier library and the idea behind GraphQL.

My intention is to extend the capability of drf-dynamic-fields library to support more functionalities like allowing to query nested fields both flat and iterable.

Contributing

We welcome all contributions. Please read our CONTRIBUTING.md first. You can submit any ideas as pull requests or as GitHub issues. If you'd like to improve code, check out the Code Style Guide and have a good time!.