Generic Api Consumer

In DCRF you can create a GenericAsyncAPIConsumer that works much like a GenericAPIView in DRF.

There are a set of mixins for the consumer that add different actions based on the CRUD operations.

  • ListModelMixin this mixin adds the action list, allows to retrieve all instances of a model class.

  • RetrieveModelMixin this mixin adds the action retrieve, allows to retrieve an object based on the pk sent.

  • PatchModelMixin this mixin adds the action patch, allows to patch an instance of a model.

  • UpdateModelMixin this mixin adds the action update, allows to update a model instance.

  • CreateModelMixin this mixin adds the action create, allows to create an instance based on the data sent.

  • DeleteModelMixin this mixin adds the action delete, allows to delete an instance based on the pk sent.

Example

This example shows how to create a basic consumer for the Django’s auth user model. We are going to create a serializer class for it and mixin with the GenericAsyncAPIConsumer the action mixins.

# serializers.py
from rest_framework import serializers
from django.contrib.auth.models import User


class UserSerializer(serializers.ModelSerializer):

    class Meta:
        model = User
        fields = ["id", "username", "email", "password"]
        extra_kwargs = {'password': {'write_only': True}}

    def create(self, validated_data):
        user = User(
            email=validated_data['email'],
            username=validated_data['username']
        )
        user.set_password(validated_data['password'])
        user.save()
        return user

# consumers.py
from django.contrib.auth.models import User
from .serializers import UserSerializer
from djangochannelsrestframework.generics import GenericAsyncAPIConsumer
from djangochannelsrestframework.mixins import (
    ListModelMixin,
    RetrieveModelMixin,
    PatchModelMixin,
    UpdateModelMixin,
    CreateModelMixin,
    DeleteModelMixin,
)

class UserConsumer(
        ListModelMixin,
        RetrieveModelMixin,
        PatchModelMixin,
        UpdateModelMixin,
        CreateModelMixin,
        DeleteModelMixin,
        GenericAsyncAPIConsumer,
):

    queryset = User.objects.all()
    serializer_class = UserSerializer

# routing.py
from django.urls import re_path
from . import consumers

websocket_urlpatterns = [
    re_path(r"^ws/$", consumers.UserConsumer.as_asgi()),
]

How to use it

First, we will create the web socket instance in javascript.

const ws = new WebSocket("ws://localhost:8000/ws/")

ws.onmessage = function(e){
    console.log(e)
}

Note

We must have a few users in our database for testing, if not, create them.

  1. List action.

ws.send(JSON.stringify({
    action: "list",
    request_id: new Date().getTime()
}))
/* The return response will be something like this.
{
    "action": "list",
    "errors": [],
    "response_status": 200,
    "request_id": 1550050,
    "data": [
        {'email': '1@example.com', 'id': 1, 'username': 'test 1'},
        {'email': '2@example.com', 'id': 2, 'username': 'test 2'},
        {'email': '3@example.com', 'id': 3, 'username': 'test 3'},
    ]
}
*/

  1. Retrieve action.

ws.send(JSON.stringify({
    action: "retrieve",
    request_id: new Date().getTime(),
    pk: 2
}))
/* The return response will be something like this.
{
    "action": "retrieve",
    "errors": [],
    "response_status": 200,
    "request_id": 1550050,
    "data": {'email': '2@example.com', 'id': 2, 'username': 'test 2'},
    }
*/

  1. Patch action.

ws.send(JSON.stringify({
    action: "patch",
    request_id: new Date().getTime(),
    pk: 2,
    data: {
        email: "edited@example.com"
    }
}))
/* The return response will be something like this.
{
    "action": "patch",
    "errors": [],
    "response_status": 200,
    "request_id": 1550050,
    "data": {'email': 'edited@example.com', 'id': 2, 'username': 'test 2'},
    }
*/

  1. Update action.

ws.send(JSON.stringify({
    action: "update",
    request_id: new Date().getTime(),
    pk: 2,
    data: {
        username: "user 2"
    }
}))
/* The return response will be something like this.
{
    "action": "update",
    "errors": [],
    "response_status": 200,
    "request_id": 1550050,
    "data": {'email': 'edited@example.com', 'id': 2, 'username': 'user 2'},
    }
*/

  1. Create action.

ws.send(JSON.stringify({
    action: "create",
    request_id: new Date().getTime(),
    data: {
        username: "new user 4",
        password: "testpassword123",
        email: "4@example.com"
    }
}))
/* The return response will be something like this.
{
    "action": "create",
    "errors": [],
    "response_status": 201,
    "request_id": 1550050,
    "data": {'email': '4@example.com', 'id': 4, 'username': 'new user 4'},
    }
*/

  1. Delete action.

ws.send(JSON.stringify({
    action: "delete",
    request_id: new Date().getTime(),
    pk: 4
}))
/* The return response will be something like this.
{
    "action": "delete",
    "errors": [],
    "response_status": 204,
    "request_id": 1550050,
    "data": null,
    }
*/

Full example

mysite/
    manage.py
    mysite/
        __init__.py
        asgi.py
        settings.py
        urls.py
        wsgi.py
    example/
        __init__.py
        consumers.py
        models.py
        serializers.py
        routing.py
        templates/
            example/
                index.html
        tests.py
        urls.py
        views.py

# serializers.py
from rest_framework import serializers
from django.contrib.auth.models import User


class UserSerializer(serializers.ModelSerializer):

    class Meta:
        model = User
        fields = ["id", "username", "email", "password"]
        extra_kwargs = {'password': {'write_only': True}}

    def create(self, validated_data):
        user = User(
            email=validated_data['email'],
            username=validated_data['username']
        )
        user.set_password(validated_data['password'])
        user.save()
        return user

# consumers.py
from django.contrib.auth.models import User
from .serializers import UserSerializer
from djangochannelsrestframework.generics import GenericAsyncAPIConsumer
from djangochannelsrestframework.mixins import (
    ListModelMixin,
    RetrieveModelMixin,
    PatchModelMixin,
    UpdateModelMixin,
    CreateModelMixin,
    DeleteModelMixin,
)


class UserConsumer(
        ListModelMixin,
        RetrieveModelMixin,
        PatchModelMixin,
        UpdateModelMixin,
        CreateModelMixin,
        DeleteModelMixin,
        GenericAsyncAPIConsumer,
):

    queryset = User.objects.all()
    serializer_class = UserSerializer

# routing.py
from django.urls import re_path
from . import consumers

websocket_urlpatterns = [
    re_path(r"^ws/$", consumers.UserConsumer.as_asgi()),
]

from django.shortcuts import render, reverse


def index(request):
    return render(request, 'example/index.html')

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Generic Api Consumer</title>
</head>
<body>

<button id="list">List</button>
<button id="retrieve">Retrieve</button>
<button id="create">Create</button>
<button id="patch">Patch</button>
<button id="update">Update</button>
<button id="delete">Delete</button>

<pre id="response"></pre>

<script>
    const ws = new WebSocket("ws://localhost:8000/ws/")

    ws.onmessage = function (e) {
        document.getElementById("response").textContent = JSON.stringify(JSON.parse(e.data), undefined, 2);
        console.log(e.data)
    }

    document.querySelector('#list').onclick = function (e) {
        ws.send(JSON.stringify({
            action: "list",
            request_id: new Date().getTime()
        }))
    };

    document.querySelector('#retrieve').onclick = function (e) {
        ws.send(JSON.stringify({
            action: "retrieve",
            request_id: new Date().getTime(),
            pk: 2
        }))
    }

    document.querySelector('#create').onclick = function (e) {
        ws.send(JSON.stringify({
            action: "create",
            request_id: new Date().getTime(),
            data: {
                username: "newuser4",
                password: "testpassword123",
                email: "4@example.com"
            }
        }))
    }

    document.querySelector('#patch').onclick = function (e) {
        ws.send(JSON.stringify({
            action: "patch",
            request_id: new Date().getTime(),
            pk: 2,
            data: {
                email: "edited@example.com"
            }
        }))
    }

    document.querySelector('#update').onclick = function (e) {
        ws.send(JSON.stringify({
            action: "update",
            request_id: new Date().getTime(),
            pk: 2,
            data: {
                username: "user 2"
            }
        }))
    }

    document.querySelector('#delete').onclick = function (e) {
        ws.send(JSON.stringify({
            action: "delete",
            request_id: new Date().getTime(),
            pk: 2
        }))
    }
</script>
</body>
</html>