Generic Api Consumer

In DCRF you can create a GenericAsyncAPIConsumer that works much like a GenericAPIView in DRF: For a more indepth look into Rest Like Websocket consumers read this blog post.

We have 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 UserSerilizer(serailizers.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 UserSerilizer
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 = UserSerilizer

# 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'},
    ]
}
*/

2. 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'},
    }
*/

3. 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'},
    }
*/

4. 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'},
    }
*/

5. Create action.

ws.send(JSON.stringify({
    action: "create",
    request_id: new Date().getTime(),
    data: {
        username: "new user 4",
        password1: "testpassword123",
        password2: "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'},
    }
*/

6. 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,
    }
*/