Django Channel實時推送與聊天

先來看一下最終的效果吧

 

開始聊天，輸入消息並點擊發送消息就可以開始聊天了

 

 

 

點擊 「獲取後端數據」開啟實時推送

先來簡單了解一下 Django Channel

Channels是一個採用Django並將其功能擴展到HTTP以外的項目，以處理WebSocket，聊天協議，IoT協議等。它基於稱為ASGI的Python規範構建。

它以Django的核心為基礎，並在其下面分層了一個完全非同步的層，以同步模式運行Django本身，但非同步處理了連接和套接字，並提供了以兩種方式編寫的選擇，從而實現了這一點。

　　詳情請參考官方文檔：//channels.readthedocs.io/en/latest/introduction.html

再簡單說下ASGI是什麼東東吧

ASGI 由 Django 團隊提出，為了解決在一個網路框架里（如 Django）同時處理 HTTP、HTTP2、WebSocket 協議。為此，Django 團隊開發了 Django Channels 插件，為 Django 帶來了 ASGI 能力。
 在 ASGI 中，將一個網路請求劃分成三個處理層面，最前面的一層，interface server（協議處理伺服器），負責對請求協議進行解析，並將不同的協議分發到不同的 Channel（頻道）；頻道屬於第二層，通常可以是一個隊列系統。頻道綁定了第三層的 Consumer（消費者）。 

 　　詳情請參考官方文檔： //channels.readthedocs.io/en/latest/asgi.html

 

下邊來說一下具體的實現步驟

 轉載請註明原文鏈接： //www.cnblogs.com/Sunzz/p/12788608.html

一、安裝channel

pip3 install channels 
pip3 install channels_redis

二、新建Django項目

1.新建項目

django-admin startproject mysite

2.新建應用

python3 manage.py startapp chat

3.編輯 mysite/settings.py文件

#註冊應用
INSTALLED_APPS = [
    ....
    'chat.apps.ChatConfig',
    "channels",
]

# 在文件尾部新增如下配置

#將ASGI_APPLICATION設置設置為指向該路由對象作為您的根應用程式：
ASGI_APPLICATION = 'mysite.routing.application'

#配置Redis
CHANNEL_LAYERS = {
    'default': {
        'BACKEND': 'channels_redis.core.RedisChannelLayer',
        'CONFIG': {
            "hosts": [('10.0.6.29', 6379)],
        },
    },
}

三、詳細程式碼與配置

1. 添加索引視圖的模板

在chat目錄中創建一個templates目錄。在您剛剛創建的templates 目錄中，創建另一個名為的目錄 chat，並在其中創建一個名為的文件index.html以保存索引視圖的模板

 將以下程式碼放入chat/templates/chat/index.html

<!-- chat/templates/chat/index.html -->
<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8"/>
    <title>Chat Rooms</title>
</head>
<body>
    What chat room would you like to enter?<br>
    <input id="room-name-input" type="text" size="100"><br>
    <input id="room-name-submit" type="button" value="Enter">

    <script>
        document.querySelector('#room-name-input').focus();
        document.querySelector('#room-name-input').onkeyup = function(e) {
            if (e.keyCode === 13) {  // enter, return
                document.querySelector('#room-name-submit').click();
            }
        };

        document.querySelector('#room-name-submit').onclick = function(e) {
            var roomName = document.querySelector('#room-name-input').value;
            window.location.pathname = '/chat/' + roomName + '/';
        };
    </script>
</body>
</html>

2.創建聊天與消息推送模板

chat/templates/chat/room.html

<!DOCTYPE html>
<html>
<head>
    <script src="//cdn.bootcdn.net/ajax/libs/jquery/3.5.0/jquery.min.js" type="text/javascript"></script>
    <link rel="stylesheet" href="//cdn.jsdelivr.net/npm/[email protected]/dist/css/bootstrap.min.css">
    <script src="//cdn.jsdelivr.net/npm/[email protected]/dist/js/bootstrap.min.js"></script>
    <meta charset="utf-8"/>
    <title>Chat Room</title>
</head>
<body>
<textarea id="chat-log" cols="150" rows="30" class="text"></textarea><br>
<input id="chat-message-input" type="text" size="150"><br>
<input id="chat-message-submit" type="button" value="發送消息" class="input-sm">
<button id="get_data" class="btn btn-success">獲取後端數據</button>
{{ room_name|json_script:"room-name" }}

<script>

    $("#get_data").click(function () {
        $.ajax({
            url: "{% url 'push' %}",
            type: "GET",
            data: {
                "room": "{{ room_name }}",
                "csrfmiddlewaretoken": "{{ csrf_token }}"
            },
        })
    });

    const roomName = JSON.parse(document.getElementById('room-name').textContent);
    const chatSocket = new WebSocket(
        'ws://' + window.location.host
        + '/ws/chat/'
        + roomName + '/'
    );
    let chatSocketa = new WebSocket(
        "ws://" + window.location.host + "/ws/push/" + roomName
    );
    chatSocket.onmessage = function (e) {
        const data = JSON.parse(e.data);
        // data 為收到後端發來的數據
        //console.log(data);
        document.querySelector('#chat-log').value += (data.message + '\n');
    };
    chatSocketa.onmessage = function (e) {
        let data = JSON.parse(e.data);
        //let message = data["message"];
        document.querySelector("#chat-log").value += (data.message + "\n");
    };


    chatSocket.onclose = function (e) {
        console.error('Chat socket closed unexpectedly');
    };
    chatSocketa.onclose = function (e) {
        console.error("Chat socket closed unexpectedly");
    };
    document.querySelector('#chat-message-input').focus();
    document.querySelector('#chat-message-input').onkeyup = function (e) {
        if (e.keyCode === 13) {  // enter, return
            document.querySelector('#chat-message-submit').click();
        }
    };

    document.querySelector('#chat-message-submit').onclick = function (e) {
        const messageInputDom = document.querySelector('#chat-message-input');
        const message = messageInputDom.value;
        chatSocket.send(JSON.stringify({
            'message': message
        }));
        messageInputDom.value = '';
    };
</script>
</body>
</html>

3.創建房間的視圖

將以下程式碼放入chat/views.py

# chat/views.py
from django.shortcuts import render
from django.http import JsonResponse
from channels.layers import get_channel_layer
from asgiref.sync import async_to_sync


def index(request):
    return render(request, "chat/index.html")


def room(request, room_name):
    return render(request, "chat/room.html", {"room_name": room_name})


def pushRedis(request):
    room = request.GET.get("room")
    print(room)

    def push(msg):
        channel_layer = get_channel_layer()
        async_to_sync(channel_layer.group_send)(
            room,
            {"type": "push.message", "message": msg, "room_name": room}
        )

    push("推送測試", )
    return JsonResponse({"1": 1})

4. 創建項目二級路由

在chat目錄下創建一個名為的文件urls.py

# mysite/chat/urls.py
from django.urls import path
from . import views

urlpatterns = [
    path('', views.index, name='index'),
　　 path('<str:room_name>/', views.room, name='room'),
]

5. 修改根路由

# mysite/urls.py

from django.contrib import admin
from django.urls import path, include
from chat.views import pushRedis

urlpatterns = [
    path('admin/', admin.site.urls),
    path("chat/", include("chat.urls")),
    path("push", pushRedis, name="push"),
]

6.創建一個消費者

文件chat/consumers.py

當Django接受HTTP請求時，它會查詢根URLconf來查找視圖函數，然後調用該視圖函數來處理該請求。同樣，當Channels接受WebSocket連接時，它會查詢根路由配置以查找使用者，然後在使用者上調用各種功能來處理來自連接的事件。

import time
import json
from channels.generic.websocket import WebsocketConsumer, AsyncWebsocketConsumer
from asgiref.sync import async_to_sync
import redis

pool = redis.ConnectionPool(
    host="10.0.6.29",
    port=6379,
    max_connections=10,
    decode_response=True,
)
conn = redis.Redis(connection_pool=pool, decode_responses=True)


class ChatConsumer(AsyncWebsocketConsumer):
    async def connect(self, ):
        self.room_name = self.scope["url_route"]["kwargs"]["room_name"]
        self.room_group_name = "chat_%s" % self.room_name

        await self.channel_layer.group_add(
            self.room_group_name,
            self.channel_name,
        )
        await self.accept()

    async def disconnect(self, close_code):
        print("close_code: ", close_code)
        await self.channel_layer.group_discard(
            self.room_group_name,
            self.channel_name
        )

    async def receive(self, text_data=None, bytes_data=None):
        text_data_json = json.loads(text_data)
        message = text_data_json["message"]
        print("receive_message：", message)
        await self.channel_layer.group_send(
            self.room_group_name,
            {
                "type": "chat_message",
                "message": message
            }
        )

    async def chat_message(self, event):
        receive_message = event["message"]
        response_message = "You message is :" + receive_message
        await self.send(text_data=json.dumps({
            "message": response_message
        }))


class PushMessage(WebsocketConsumer):

    def connect(self):
        self.room_group_name = self.scope["url_route"]["kwargs"]["room_name"]
        async_to_sync(self.channel_layer.group_add)(
            self.room_group_name,
            self.channel_name
        )
        self.accept()

    def disconnect(self, code):
        async_to_sync(self.channel_layer.group_discard)(
            self.room_group_name,
            self.channel_name
        )

    def push_message(self, event):
        """
        主動推送
        :param event:
        :return:
        """
        print(event, type(event))
        while True:
            time.sleep(2)
            msg = time.strftime("%Y-%m-%d %H:%M:%S") + "---  room_name: %s" % event["room_name"]
            self.send(text_data=json.dumps(
                {"message": msg}
            ))

7.為項目添加websocket的路由配置

在chat目錄下創建一個名為的文件routing.py

# mysite/chat/routing.py

from django.urls import re_path, path
from . import consumers

websocket_urlpatterns = [
    re_path(r"ws/chat/(?P<room_name>\w+)/$", consumers.ChatConsumer),
    path("ws/push/<room_name>", consumers.PushMessage),
]

8.配置websocket根路由

與setting同級目錄新建ws根路由文件 routing.py

from channels.routing import ProtocolTypeRouter, URLRouter
from channels.auth import AuthMiddlewareStack
import chat.routing

application = ProtocolTypeRouter({
    "websocket": AuthMiddlewareStack(
        URLRouter(
            chat.routing.websocket_urlpatterns
        )
    ),
})

9.最終的文件關係如下圖 

10.啟動服務

python3 manage.py runserver 10.0.6.2:80

注意看，這和django是不一樣的

 

還有另一種更穩健的啟動方式

和setting同級新增文件 asgi.py

import os
import django
from channels.routing import get_default_application

os.environ.setdefault("DJANGO_SETTINGS_MODULE", "mysite.settings")
django.setup()
application = get_default_application()

啟動方式為：

daphne -b 10.0.6.2 -p 80 mysite.asgi:application
daphne 在安裝channel時已經自動安裝好了

 參考：

　　//channels.readthedocs.io/en/latest/tutorial/index.html

　　//blog.ernest.me/post/asgi-demonstration-realtime-blogging

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