Django Channel实时推送与聊天
先来看一下最终的效果吧
开始聊天，输入消息并点击发送消息就可以开始聊天了
点击 “获取后端数据”开启实时推送
先来简单了解一下 Django Channel
Channels是一个采用Django并将其功能扩展到HTTP以外的项目，以处理WebSocket，聊天协议，IoT协议等。它基于称为ASGI的Python规范构建。
它以Django的核心为基础，并在其下面分层了一个完全异步的层，以同步模式运行Django本身，但异步处理了连接和套接字，并提供了以两种方式编写的选择，从而实现了这一点。
详情请参考官方文档：https://channels.readthedocs.io/en/latest/introduction.html
再简单说下ASGI是什么东东吧
ASGI 由 Django 团队提出，为了解决在一个网络框架里（如 Django）同时处理 HTTP、HTTP2、WebSocket 协议。为此，Django 团队开发了 Django Channels 插件，为 Django 带来了 ASGI 能力。
在 ASGI 中，将一个网络请求划分成三个处理层面，最前面的一层，interface server（协议处理服务器），负责对请求协议进行解析，并将不同的协议分发到不同的 Channel（频道）；频道属于第二层，通常可以是一个队列系统。频道绑定了第三层的 Consumer（消费者）。
详情请参考官方文档： https://channels.readthedocs.io/en/latest/asgi.html
下边来说一下具体的实现步骤
转载请注明原文链接： https://www.cnblogs.com/Sunzz/p/12788608.html
一、安装channel
pip3 install channels pip3 install channels_redis
二、新建Django项目
1.新建项目
django-admin startproject mysite
2.新建应用
python3 manage.py startapp chat
3.编辑 <span>mysite/settings.py</span>文件
#注册应用
INSTALLED_APPS = [
....
‘chat.apps.ChatConfig‘,
"channels",
]
# 在文件尾部新增如下配置#将ASGI_APPLICATION设置设置为指向该路由对象作为您的根应用程序：
ASGI_APPLICATION = ‘mysite.routing.application‘
#配置Redis
CHANNEL_LAYERS = {
‘default‘: {
‘BACKEND‘: ‘channels_redis.core.RedisChannelLayer‘,
‘CONFIG‘: {
"hosts": [(‘10.0.6.29‘, 6379)],
},
},
}三、详细代码与配置
1. 添加索引视图的模板
在<span>chat</span>目录中创建一个templates目录。在您刚刚创建的templates 目录中，创建另一个名为的目录 <span>chat</span>，并在其中创建一个名为的文件<span>index.html</span>以保存索引视图的模板
将以下代码放入<span>chat/templates/chat/index.html</span>
<!-- 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.创建聊天与消息推送模板
chat/templates/chat/room.html
<!DOCTYPE html>
<html>
<head>
<script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.5.0/jquery.min.js" type="text/javascript"></script>
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm//dist/css/bootstrap.min.css">
<script src="https://cdn.jsdelivr.net/npm//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="发送消息" class="input-sm">
<button id="get_data" class="btn btn-success">获取后端数据</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 为收到后端发来的数据
//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.创建房间的视图
将以下代码放入<span>chat/views.py</span>
# 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("推送测试", )
return JsonResponse({"1": 1})4. 创建项目二级路由
在chat目录下创建一个名为的文件<span>urls.py</span>
# 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.pyfrom 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.创建一个消费者
文件<span>chat/consumers.py</span>
当Django接受HTTP请求时，它会查询根URLconf来查找视图函数，然后调用该视图函数来处理该请求。同样，当Channels接受WebSocket连接时，它会查询根路由配置以查找使用者，然后在使用者上调用各种功能来处理来自连接的事件。
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):
"""
主动推送
: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.为项目添加websocket的路由配置
在chat目录下创建一个名为的文件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
与setting同级目录新建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.最终的文件关系如下图
10.启动服务
python3 manage.py runserver 10.0.6.2:80
注意看，这和django是不一样的
还有另一种更稳健的启动方式
和setting同级新增文件 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()启动方式为：
daphne -b 10.0.6.2 -p 80 mysite.asgi:application
daphne 在安装channel时已经自动安装好了
参考：
https://channels.readthedocs.io/en/latest/tutorial/index.html
https://blog.ernest.me/post/asgi-demonstration-realtime-blogging