django使用websocket

    WebSocket协议是基于TCP的一种新的协议。WebSocket最初在HTML5规范中被引用为TCP连接，作为基于TCP的套接字API的占位符。它实现了浏览器与服务器全双工(full-duplex)通信。其本质是保持TCP连接，在浏览器和服务端通过Socket进行通信。

django 使用websocket需要安装channels

pip3 install channels==2.3 -i https://pypi.tuna.tsinghua.edu.cn/simple

创建django项目

　　在settings.py里注册channels

INSTALLED_APPS = [
    ‘django.contrib.admin‘,
    ‘django.contrib.auth‘,
    ‘django.contrib.contenttypes‘,
    ‘django.contrib.sessions‘,
    ‘django.contrib.messages‘,
    ‘django.contrib.staticfiles‘,
    ‘app01.apps.App01Config‘,
    # 项目中要使用channels做websocket了.
    "channels",
]

本质: channels会把原来只支持http协议的wsgi,换成支持http和websocket协议的asgi

配置application

# settings.py 

INSTALLED_APPS = [
    ‘django.contrib.admin‘,
    ‘django.contrib.auth‘,
    ‘django.contrib.contenttypes‘,
    ‘django.contrib.sessions‘,
    ‘django.contrib.messages‘,
    ‘django.contrib.staticfiles‘,
    ‘app01.apps.App01Config‘,
    # 项目中要使用channels做websocket了.
    "channels",
]

ASGI_APPLICATION = "channel_demo.routing.application"

# channel_demo/routing.py（新建routing.py文件）
from channels.routing import ProtocolTypeRouter, URLRouterfrom django.conf.urls import urlfrom app01 import consumersapplication = ProtocolTypeRouter({    ‘websocket‘: URLRouter([        url(r‘^chat/$‘, consumers.ChatConsumer),    ])})

app下建立consumers文件

和view文件功能一样，专门处理websocket请求

from channels.generic.websocket import WebsocketConsumer
from channels.exceptions import StopConsumer

CONSUMER_OBJECT_LIST = []

class ChatConsumer(WebsocketConsumer):

    def websocket_connect(self, message):
        """
        客户端发来连接请求之后就会被触发
        :param message:
        :return:
        """
        # 服务端接收连接,向客户端浏览器发送一个加密字符串
        self.accept()
        # 连接成功
        CONSUMER_OBJECT_LIST.append(self)

    def websocket_receive(self, message):
        """
        客户端浏览器向服务端发送消息,此方法自动触发
        :param message:
        :return:
        """
        # 服务端给客户端回一条消息
        # self.send(text_data=message[‘text‘])
        for obj in CONSUMER_OBJECT_LIST:
            obj.send(text_data=message[‘text‘])
    def websocket_disconnect(self, message):
        """
        客户端主动断开连接
        :param message:
        :return:
        """
        # 服务端断开连接
        CONSUMER_OBJECT_LIST.remove(self)
        raise StopConsumer()