Tutorial: Create a real-time web game with Django Channels and React

Jan 20, 2017

A functional lobby

The lobby will act as a public place to create and join other users’ games. So, we’re going to have two components to provide this: Available Games and Player Games.

Let’s start with the Player Games component. This component will list any games the user is currently involved in as well as provide a button to create a new game that will be public for other players to join.

Create a PlayerGames.jsx file in your lobby folder with the following code:

import React from 'react'

class PlayerGames extends React.Component{
  constructor(props) {
      super(props)
      this.state = {
        game_list: this.props.game_list
      }

      // bind button click
     this.onCreateGameClick = this.onCreateGameClick.bind(this);
     this.renderButton = this.renderButton.bind(this);
     this.renderOpponent = this.renderOpponent.bind(this)
    }

    onCreateGameClick(event) {
        this.props.sendSocketMessage({action: "create_game"})
    }


    componentWillReceiveProps(newProp){
        this.setState({game_list: newProp.game_list})
    }

    renderButton(game){
         if (game.completed){
            return "View"
         } else if (game.opponent == null && game.creator.id == this.props.player.id){
             return "Waiting..."
         } else{
             return "Play"
         }
                                     
    }

    renderOpponent(game){
        console.log(game)
        if (game.opponent != null){
            return game.opponent.username
        } else {
            return "???"
        }
    }

    renderGameList(){
        if (this.props.game_list.length > 0){
            return this.props.game_list.map(function(game){
                    return <li key={game.id} className="list-group-item">
                                <span className="badge pull-left">{game.id}</span>&nbsp;&nbsp;
                                <span>{game.creator.username}</span> vs <span>{this.renderOpponent(game)}</span>

                                <a className="btn btn-sm btn-primary pull-right" href={"/game/"+game.id+"/"}>{this.renderButton(game)}</a>
                            </li>
                    }, this)

        }else{
            return ("No Games")
        }
    }

    render() {
      return (
        <div>
          <div className="panel panel-primary">
                <div className="panel-heading">
                    <span>Your Games</span>
                    <a href="#" className="pull-right badge" onClick={this.onCreateGameClick} id="create_game">Start New Game</a>
                </div>
                <div className="panel-body">
                    <div>
                        <ul className="list-group games-list">
                            {this.renderGameList()}
                        </ul>
                    </div>
                </div>
            </div>

        </div>
      )
    }
}

PlayerGames.defaultProps = {

};

PlayerGames.propTypes = {
    game_list: React.PropTypes.array,
    player: React.PropTypes.object
};


export default PlayerGames

import React from 'react'

class PlayerGames extends React.Component{

constructor(props) {

super(props)

this.state = {

game_list: this.props.game_list

}

// bind button click

this.onCreateGameClick = this.onCreateGameClick.bind(this);

this.renderButton = this.renderButton.bind(this);

this.renderOpponent = this.renderOpponent.bind(this)

}

onCreateGameClick(event) {

this.props.sendSocketMessage({action: "create_game"})

}

componentWillReceiveProps(newProp){

this.setState({game_list: newProp.game_list})

}

renderButton(game){

if (game.completed){

return "View"

} else if (game.opponent == null && game.creator.id == this.props.player.id){

return "Waiting..."

} else{

return "Play"

}

renderOpponent(game){

console.log(game)

if (game.opponent != null){

return game.opponent.username

} else {

return "???"

}

renderGameList(){

if (this.props.game_list.length > 0){

return this.props.game_list.map(function(game){

return <li key={game.id} className="list-group-item">

<span>{game.creator.username}</span> vs <span>{this.renderOpponent(game)}</span>

<a className="btn btn-sm btn-primary pull-right" href={"/game/"+game.id+"/"}>{this.renderButton(game)}</a>

</li>

}, this)

}else{

return ("No Games")

}

render() {

return (

<div>

<span>Your Games</span>

<a href="#" className="pull-right badge" onClick={this.onCreateGameClick} id="create_game">Start New Game</a>

</div>

<div>

{this.renderGameList()}

</ul>

</div>

)

}

PlayerGames.defaultProps = {

};

PlayerGames.propTypes = {

game_list: React.PropTypes.array,

player: React.PropTypes.object

};

export default PlayerGames

You’ve seen some of this already in our LobbyBase component, but there’s several new things going on here:

Line 16-18: onCreateGameClick(event) handles the create game button click. It simply calls the channels backend with a message to create a new game.
Line 21-23: componentWillReceiveProps(newProp) method is only fired off when props have changed, but not on the initial render. newProp (can be named anything) holds the new props. This method is useful to update the state of the component, which will cause a re-render with the newest props. This is what we’re doing in that method.
Lines 25-59: These lines contain three methods that render out pieces of the component. In React, the main render() method isn’t suited to handle much logic. When you find that you need to loop through an array or apply some conditional logic to determine how a piece is rendered, you should put that in a method like these. In our render() method on line 72, you’ll find {this.renderGameList()} which calls one of our three methods, which in turn uses the other two methods to render parts within it. We could have added all of that into the single renderGameList() method, but I prefer to break it out to make it a bit cleaner.

A break-down of those methods, if you’re interested:

renderGameList(): Loops through all of the games from the array (game_list) provided to the component through props which will be sent from LobbyBase (we’ll get there in a minute). For each of the games in the list, we’re creating an list element (<li>) which displays the game.id and creator.username. It also calls the other two methods – renderOpponent() and renderButton()

renderOpponent(): Simply checks to see if there is an opponent yet. If so, displays their name. Otherwise, displays “???”.

renderButton(): Checks the status of the game and renders the game’s button with the appropriate status: “View” if already completed, “Waiting…” if there is no opponent, or “Play” if there’s an opponent and the game is live.

Now, add that new component to the LobbyBase component so it will render. We’ll also add some supporting methods – all new code is highlighted

import React from 'react';
import ReactDOM from 'react-dom';
import Websocket from 'react-websocket'
import $ from 'jquery'
import PlayerGames from './PlayerGames'

class LobbyBase extends React.Component {

    constructor(props) {
        super(props);
        this.state = {
            player_game_list: [],
            available_game_list: []
        }

        // bind button click
        this.sendSocketMessage = this.sendSocketMessage.bind(this);
    }

    getPlayerGames(){
        this.serverRequest = $.get('http://localhost:8080/player-games/?format=json', function (result) {
           this.setState({
            player_game_list: result,
             })
        }.bind(this))
    }

    componentDidMount() {
       this.getPlayerGames()
    }

    componentWillUnmount() {
        this.serverRequest.abort();
    }

    handleData(data) {
        //receives messages from the connected websocket
        let result = JSON.parse(data)
        // new games, so get an updated list of this player's game
        this.getPlayerGames()
        // we've received an updated list of available games
        this.setState({available_game_list: result})
    }

    sendSocketMessage(message){
        // sends message to channels back-end
       const socket = this.refs.socket
       socket.state.ws.send(JSON.stringify(message))
    }

    render() {
        return (

            <div className="row">
                <Websocket ref="socket" url={this.props.socket}
                    onMessage={this.handleData.bind(this)} reconnect={true}/>
                <div className="col-lg-4">
                    <PlayerGames player={this.props.current_user} game_list={this.state.player_game_list}
                                 sendSocketMessage={this.sendSocketMessage} />
                </div>
            </div>

        )
    }
}

LobbyBase.propTypes = {
    socket: React.PropTypes.string
};

export default LobbyBase;

import React from 'react';

import ReactDOM from 'react-dom';

import Websocket from 'react-websocket'

import $ from 'jquery'

import PlayerGames from './PlayerGames'

class LobbyBase extends React.Component {

constructor(props) {

super(props);

this.state = {

player_game_list: [],

available_game_list: []

}

// bind button click

this.sendSocketMessage = this.sendSocketMessage.bind(this);

}

getPlayerGames(){

this.serverRequest = $.get('http://localhost:8080/player-games/?format=json', function (result) {

this.setState({

player_game_list: result,

})

}.bind(this))

}

componentDidMount() {

this.getPlayerGames()

}

componentWillUnmount() {

this.serverRequest.abort();

}

handleData(data) {

//receives messages from the connected websocket

let result = JSON.parse(data)

// new games, so get an updated list of this player's game

this.getPlayerGames()

// we've received an updated list of available games

this.setState({available_game_list: result})

}

sendSocketMessage(message){

// sends message to channels back-end

const socket = this.refs.socket

socket.state.ws.send(JSON.stringify(message))

}

render() {

return (

<Websocket ref="socket" url={this.props.socket}

onMessage={this.handleData.bind(this)} reconnect={true}/>

<PlayerGames player={this.props.current_user} game_list={this.state.player_game_list}

sendSocketMessage={this.sendSocketMessage} />

</div>

)

}

LobbyBase.propTypes = {

socket: React.PropTypes.string

};

export default LobbyBase;

So, here’s what we added:

Line 5: Importing the PlayerGames component
Lines 20-26: The getPlayerGames() method. This method calls out to the server to retrieve the current user’s game list (we still need to implement this server-side)
Lines 28-30: componentDidMount() is the React lifecycle method mentioned earlier. This occurs before render, and in this case will call the new method we just provided.
Lines 39-41: The handleData() method handles the message from the server over the websocket, sent by Channels. We’re using this here to call getPlayerGames() and update the game list.
Lines 57-60: Adding in the PlayerGames component to the render method.

Webpack –watch

At this point, I recommend keeping a separate terminal window open to run webpack in “watch mode.” This ensures the bundle files have the latest changes at all times as webpack will continue to monitor the files for any changes, and update the bundles immediately. So, open another terminal, move to the directory of your project, and run this:

./node_modules/.bin/webpack --config webpack.config.js --watch

1	./node_modules/.bin/webpack --config webpack.config.js --watch

Once webpack does its thing, you can runserver again and you should see the following screen. If you don’t, be sure to log in as one of the two players you created earlier.

You will, however, find that there is an error in your browser console. It’s a 404 error references /player-games/. This may be obvious to you when you saw our LobbyBase.jsx code. We have a few things that aren’t fully implemented yet, so let’s work on those. To start that, we’ll need something that will help send/receive JSON data through AJAX calls.

One way is to use the django-rest-framework…

1 2 3 4 5 6 7 8 9

Comments

hello,
when I run your code, but the web don’t show the game, what’s happend?

Gia Cat 09/27/2018 12:34 pm Reply
- Are you going through the tutorial? Or are you running the example project from github?
  
  codyparker 09/28/2018 8:46 am Reply
Do you have a similar project but with channels 2.0? Do you plan to update this one?

marsel 08/30/2018 9:53 am Reply
- Yes, I’m actually working on one now. Hopefully I’ll have it ready in October, but my free time is tight right now.
  
  codyparker 09/28/2018 8:47 am Reply
I am getting an error, “ImportError: cannot import name ‘Group'”, while trying to import Group from channels in models.py. I am using channels 2.0.2. Please help.

don 03/28/2018 8:31 am Reply
- Yeah, this tutorial is based on a very early version of channels – 0.17, I believe. Version 2.0.2 has quite of few changes from that old version, including requiring Python3. Here is an issue on the official github that deals with the error you’re seeing: https://github.com/django/channels/issues/989
  
  I will try to get the tutorial updated to Django 2.0, Python 3, and the latest channels version soon.
  
  codyparker 04/23/2018 9:15 pm Reply
Hey,

I’m trying to follow your tutorial, but I keep running into the following error:

OSError at /lobby/
Error reading [PATH]\webpack-stats.json. Are you sure webpack has generated the file and the path is correct?

Any idea how to fix it?

Graeme 03/14/2018 10:32 am Reply
- Sorry, I didn’t reply sooner. If the file is being generated, check your STATS_FILE setting under WEBPACK_LOADER in settings.py. It’s possible that it isn’t pointing to the correct location for the file.
  
  If the file isn’t being generated, webpack may not be running properly. Are you seeing errors when you run wepback?
  
  codyparker 04/23/2018 9:24 pm Reply
That is very good, I was making similar stuff as a video on my language and this sharing is very useful.
Power of sharing, thanks again.

ozan 10/29/2017 3:48 pm Reply
When will the index.jsx be called ?

Orang 10/08/2017 6:30 pm Reply
- The index.jsx files are bundled with webpack (set on lines 8 and 9 in webpack.config.js). Those are the bundles that are loaded with the Django Webpack Loader and rendered on the related html pages (lobby.html and game.html).
  
  codyparker 10/09/2017 10:07 am Reply
I got a few questions to make the game a little bit more complex

Is it possible to allow to the user give a name for the room?
Is it possible to allow more than 2 players? (obviously adding the correct img stuff)
If the answer from above is yes, can the user choose a “limit” for ppl to connect before starting the game?

Cheers!

Leonardo 10/06/2017 7:19 pm Reply
- Yes, each of those suggestions would work just fine:
  1. Name of the room: Adding a “name” CharField to the Game model (models.py) would hold the value and then you would just need to add a bit to the create_new model method to set it. You would also need to allow the game creator to provide that name when creating it, instead of just clicking a button. But that name value would then just be passed along in the JSON to Channels in the sendSocketMessage call in the onCreateGameClick() method of PlayerGames.jsx.
  2. This could be added with a bit more work, but essentially you would want to change the Game model to have a ManyToMany relationship to Users. Aside from that, several other parts of the code and GUI would need to be updated because it’s pretty hardcoded to two players at the moment. But if there were multiple users in a game, Channels would work the same – everyone would get game updates without a problem.
  3. And yes, once the game was converted to use multiple players in a game, you could just have the game creator specify the max limit and then store that as a max_players IntegerField in the Game model….and then allow users to join up to that limit.
  codyparker 10/09/2017 10:20 am Reply
Thanks for this django/react tutorial. It is awesome helping me get my head around React and putting all the pieces together!!

johnedstone 08/12/2017 8:05 am Reply
- Great to hear! I’m glad you found it useful. Thanks for letting me know.
  
  codyparker 08/12/2017 4:21 pm Reply
Thank you so much for writing this tutorial!
From your description, it seems like moves and player messages should update automatically, however when I run it, they only update after a manual refresh of the page. Am I misunderstanding how the website works?
Thanks

Missa 07/26/2017 12:58 pm Reply
- The log should update when new chat messages are created or moves are made. I would check to make sure the game.send_game_update() method is being called at the appropriate times. Also, check the browser console for any errors on the client-side. That may give you more of a clue to the issue as well.
  
  codyparker 07/26/2017 1:48 pm Reply
Thanks for writing this tutorial! However, some things that may be confusing to a beginner: startapp game is going to create a game/views.py by default, and anyone that forgets to move views.py is going to have a package conflict. Also, from views import * inside __init__.py should be from .views import * just to avoid any namespace mismatches. I recommend you keep the default views.py.

Daniel 06/11/2017 2:41 pm Reply
- Thanks for your comments, Daniel. Yes, I thought that splitting the views could be confusing, but it’s something I like to do to organize views of different types. So here, I didn’t want to combine the DRF API views with the “standard” Django views. Also, the tutorial wasn’t exactly intended for beginners, but maybe I can clarify the views split a little more in the post. Also, thanks for catching the import fix. I had already updated the imports in the git project, but missed it in the post.
  
  codyparker 06/13/2017 10:11 am Reply
Hello! Great tutorial! I have a question, I want to use foundation-sites in my project. I am following you tutorial and instead of using bootstrap precompiled css I would like to install foundation with bower maybe? I know how to use the “foundation new” command to create a new project but I would like not to create a new project but integrate foundation sites with mine!

David Anchorena 06/05/2017 8:45 am Reply
- Hey David, sorry I haven’t worked with Foundation yet. But it looks like you can just use the CSS itself and avoid the CLI site generation: http://foundation.zurb.com/sites/download/
  
  You could just include this as you would any other CSS, and my guess is that if you install the full Foundation package with NPM, you could just reference the CSS there as well.
  
  codyparker 06/06/2017 2:38 pm Reply
not sure if it’s a django versioning thing or what, but on page 1 of this tutorial you are no longer allowed to specify views with strings and they must be callable, suggested edit follows:

original:

from django.conf.urls import url
from django.contrib import admin
from game.views import *

urlpatterns = [
url(r’^admin/’, admin.site.urls),
url(r’^register/’, CreateUserView.as_view()),
url(r’^login/$’, ‘django.contrib.auth.views.login’, {‘template_name’: ‘login.html’}),
url(r’^logout/$’, ‘django.contrib.auth.views.logout’, {‘next_page’: ‘/’}),

url(r’^$’, HomeView.as_view())
]

edit:

from django.conf.urls import url
from django.contrib import admin
from django.contrib.auth.views import login, logout
from game.views import *

urlpatterns = [
url(r’^admin/’, admin.site.urls),
url(r’^register/’, CreateUserView.as_view()),
url(r’^login/$’, login, {‘template_name’: ‘login.html’}),
url(r’^logout/$’, logout, {‘next_page’: ‘/’}),

url(r’^$’, HomeView.as_view())
]

will 05/23/2017 9:21 am Reply
- Yep – you’re right, thanks for letting me know! I’ve updated the urls.py code.
  
  codyparker 05/23/2017 12:30 pm Reply
Thank you so much, one of the most complete tutorials I have seen. Not all persons are willing to teach this things together, and the complexity of the scenario gives us good bases. This types of tutorials (even paid) are hard to find. Again, thank you.

Pepe 05/07/2017 9:14 pm Reply
- Thank you for the nice comments! I’m glad you found the tutorial helpful.
  
  codyparker 05/08/2017 8:35 am Reply
Can you please show one example on how I can make api post call from react to django drf?

Is there any reason why all “post” calls are done via sockets not api in this tutorial?

Said 02/07/2017 3:47 am Reply
- You can see a few examples of calls from React to the DRF backend in my post. For example, take a look at the getGame() method on the GameBoard.jsx component. That method calls the DRF SingleGameViewSet endpoint to get game details.
  
  And as I mentioned in the post, I tried to mix up different ways of getting data from the Django backend to the React frontend. I wanted to show different ways of achieving the same thing: sending data through the standard Django response via context, DRF calls to the backend, and Django Channels websocket calls. In reality, this isn’t how I would structure a production app, but I was hoping it would be informative. Hopefully not confusing at the same time.
  
  codyparker 02/07/2017 2:40 pm Reply
Wow! Thanks again for sharing this tutorial. I am amazed by your generosity. The tutorial is intense.

Let me give some suggesting for how you can improve it. I found that very often the flow of tutorial is going from big concepts (code snippets) to a smaller ones. For example several times you are first putting together some views, react components or api_views and then go to show some serializers, consumers, routers, urls and so on. This can be sometimes confusing, since a student can receive error messages that those small parts are not yet existed. I think going from small concepts to bigger would be more easily to understand. Also, please check your github code. I think it does not work if you just download it and want to use. Several imports are configured improperly (signal in apps.py, for instance)

Thank you again!

Said 02/07/2017 3:44 am Reply
- Thanks for suggestions. Yes this was my first large tutorial so it definitely could be optimized and improved. I did the GitHub project well before the post, but it worked for me when I last tried it. It could be a python2/python3 import issue. I’ll update that tonight and get it working.
  
  codyparker 02/07/2017 1:16 pm Reply
not sure if the instruction on page 8 is correct

class ClaimSquareView(APIView):

def get_object(self, pk):
try:
return Game.objects.get(pk=pk)
except Game.DoesNotExist:
raise Http404

def put(self, request, pk):
game = self.get_object(pk)
# update the owner
print(game)
return Response(serializer.errors)

– no import for Http404
– serializer is not defined

Said 02/07/2017 1:36 am Reply
- You’re right! That view isn’t even needed… I think I started going that direction to claim a square, but moved it to a Channels call using the consumer instead. I’ve removed that reference and the url reference.
  
  Thank you very much for your suggestions and bug reports! I’ve added you to the “Thank you” section at the bottom of the post.
  
  codyparker 02/07/2017 3:50 pm Reply
on page 7 views.py also should import

from django.contrib import messages

Said 02/07/2017 12:31 am Reply
- Added it, thank you.
  
  codyparker 02/07/2017 3:51 pm Reply
Also, in my setup in view/__init__.py instead of

from views import *
from api_views import *

I need to enter

from .views import *
from .api_views import *

Said 02/06/2017 10:34 pm Reply
- Yes this is probably because you’re on Python 3 and implicit relative imports like that won’t work. I’m on 2.7 and they work with it. Thanks for pointing that out. I’ll update the post to note this.
  
  codyparker 02/07/2017 1:12 pm Reply
on the page 2, it is very important to highlights this setting in the settings.py

STATICFILES_DIRS = [
os.path.join(BASE_DIR, “static”),
]

it is not something that is added by default if start project with django-admin tools

Said 02/06/2017 9:37 pm Reply
- Thanks, yes when I first talk about the settings file, I recommended overwriting all of the default code with what I show in the post. I’ll make sure that it’s more clear.
  
  codyparker 02/07/2017 5:17 pm Reply
Thanks, confirm MIDDLEWARE_CLASSES fixed the issue with ‘AsgiRequest’ object has no attribute ‘session’

Said 02/06/2017 9:23 pm Reply
after following all instruction on the page 4, cannot login, getting this error

AttributeError at /login/
‘AsgiRequest’ object has no attribute ‘session’
Request Method: POST
Request URL: http://127.0.0.1:8080/login/
Django Version: 1.9.12
Exception Type: AttributeError
Exception Value:
‘AsgiRequest’ object has no attribute ‘session’
Exception Location: /home/gideon/virtualenvs/vEnv_my_obstruct_game/lib/python3.4/site-packages/django/contrib/auth/__init__.py in login, line 101
Python Executable: /home/gideon/virtualenvs/vEnv_my_obstruct_game/bin/python
Python Version: 3.4.3
Python Path:
[‘/home/gideon/PycharmProjects/my_obstruct_game’,
‘/home/gideon/virtualenvs/vEnv_my_obstruct_game/lib/python3.4/site-packages/setuptools-18.1-py3.4.egg’,
‘/home/gideon/virtualenvs/vEnv_my_obstruct_game/lib/python3.4/site-packages/pip-7.1.0-py3.4.egg’,
‘/home/gideon/PycharmProjects/my_obstruct_game’,
‘/usr/lib/python3.4’,
‘/usr/lib/python3.4/plat-x86_64-linux-gnu’,
‘/usr/lib/python3.4/lib-dynload’,
‘/home/gideon/virtualenvs/vEnv_my_obstruct_game/lib/python3.4/site-packages’]
Server time: Mon, 6 Feb 2017 15:53:42 +0000
Traceback Switch to copy-and-paste view

/home/gideon/virtualenvs/vEnv_my_obstruct_game/lib/python3.4/site-packages/django/core/handlers/base.py in get_response
response = self.process_exception_by_middleware(e, request) …
▶ Local vars
/home/gideon/virtualenvs/vEnv_my_obstruct_game/lib/python3.4/site-packages/channels/handler.py in process_exception_by_middleware
return super(AsgiHandler, self).process_exception_by_middleware(exception, request)

Said 02/06/2017 9:55 am Reply
- One thing that could cause this with Django 1.9+ is if you have MIDDLEWARE instead of MIDDLEWARE_CLASSES in your settings.py file. Can you check that?
  
  codyparker 02/06/2017 10:28 am Reply
It seems there is an error in this instruction

npm install –save-dev react react-dom webpack webpack-bundle-tracker babel-core babel babel-loadernpm babel-preset-es2015 react-websocket babel-preset-es2015 babel-preset-react jquery

“babel-loadernpm” should read “babel-loader”

Said Akhmedbayev 02/05/2017 11:28 pm Reply
- Yep, you’re right – a little copy-paste issue on my part. It’s fixed now. Thanks for letting me know!
  
  codyparker 02/06/2017 9:06 am Reply
I have not yet finished your tutorial, but for what I see I can tell you huge THANK YOU!

Said 02/05/2017 10:33 am Reply
- Thank you, I hope it you find it useful. Please let me know if you have any issues!
  
  codyparker 02/06/2017 9:07 am Reply

Tutorial: Create a real-time web game with Django Channels and React

A functional lobby

Webpack –watch

One way is to use the django-rest-framework…

How to activate your virtual environment in the PyCharm terminal

Django Quick Tip – Bulk Inserts

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