近期有一需求：前端页面点击执行任务，实时显示后端执行情况，思考一波；发现WebSocket最适合做这件事。

效果

测试ping www.baidu.com效果

点击连接建立ws连接

后端实现

所需软件包

后端主要借助DjangoChannels实现socket连接，官网文档链接

这里想实现每个连接进来加入组进行广播，所以还需要引入channels-redis。

pip

channels==2.2.0
channels-redis==2.4.0

引入

settings.py

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'rest_framework.authtoken',
    'rest_framework',
                ...
    'channels',
]

# Redis配置
REDIS_HOST = ENV_DICT.get('REDIS_HOST', '127.0.0.1')
REDIS_PORT = ENV_DICT.get('REDIS_PORT', 6379)
CHANNEL_LAYERS = {
    "default": {
        "BACKEND": "channels_redis.core.RedisChannelLayer",
        "CONFIG": {
            "hosts": [(REDIS_HOST, REDIS_PORT)],
        },
    },
}

代码

apps/consumers.py

新建一个消费处理

实现： 默认连接加入组，发送信息时的处理。

from channels.generic.websocket import WebsocketConsumer

class MyConsumer(WebsocketConsumer):
    def connect(self):
        """
        每个任务作为一个频道
        默认进入对应任务执行频道
        """
        self.job_name = self.scope['url_route']['kwargs']['job_name']
        self.job_group_name = 'job_%s' % self.job_name
        async_to_sync(self.channel_layer.group_add)(
            self.job_group_name,
            self.channel_name
        )
        self.accept()

    def disconnect(self, close_code):
        async_to_sync(self.channel_layer.group_discard)(
            self.job_group_name,
            self.channel_name
        )

    # job.message类型处理
    def job_message(self, event):

        # 默认发送收到信息
        self.send(text_data=event["text"])

apps/routing.py

ws类型路由

实现：ws/job/由MyConsumer去处理。

from . import consumers
from django.urls import path
from channels.routing import ProtocolTypeRouter,  URLRouter
from channels.sessions import SessionMiddlewareStack

application = ProtocolTypeRouter({
    'websocket': SessionMiddlewareStack(
        URLRouter(
          [
              path('ws/job/', consumers.MyConsumer)
          ]
        )
    ),
})

apps/views.py

在执行命令中获取webSocket消费通道，进行异步推送

  • 使用异步推送async_to_sync是因为在连接的时候采用的异步连接，所以推送必须采用异步推送。
  • 因为执行任务时间过长，启动触发运行时加入多线程，直接先返回ok，后端运行任务。
from subprocess  import Popen,PIPE
import threading

def runPopen(job):
    """
    执行命令,返回popen
    """
    path = os.path
    Path = path.abspath(path.join(BASE_DIR, path.pardir))
    script_path = path.abspath(path.join(Path,'run.sh'))
    cmd = "sh %s %s" % (script_path, job)
    return Popen(cmd, shell=True, stdout=PIPE, stderr=PIPE)

def runScript(job):
    channel_layer = get_channel_layer()
    group_name = "job_%s" % job

    popen = runPopen(job)
    while True:
        output = popen.stdout.readline()
        if output == '' and popen.poll() is not None:
            break

        if output:
            output_text = str(output.strip())
            async_to_sync(
                channel_layer.group_send
                )(
                    group_name, 
                    {"type": "job.message", "text": output_text}
                )
        else:
            err  = popen.stderr.readline()
            err_text = str(err.strip())
            async_to_sync(
                channel_layer.group_send
                )(
                    group_name,
                    {"type": "job.message", "text": err_text}
                )
            break

class StartJob(APIView):  
    def get(self, request, job=None):
        run =  threading.Thread(target=runScript, args=(job,))
        run.start()
        return HttpResponse('ok')

apps/urls.py

get请求就能启动任务

urlpatterns = [
                ...
    path('start_job/', StartJob.as_view())
]

前端实现

所需软件包

vue-native-websocket

代码实现

plugins/vueNativeWebsocket.js

import Vue from 'vue'
import VueNativeSock from '../utils/socket/Main.js'

export default function ({ store }) {
  Vue.use(VueNativeSock, 'http://localhost:8000/ws/job', {connectManually: true,});
}

nuxt.config.js

配置文件引入， 这里我使用的是nuxt框架

  plugins: [ 
      { 
        src: '@/plugins/vueNativeWebsocket.js', 
        ***: false 
      },
    ],

封装socket

export default (connection_url, option) => {
    // 事件
    let event = ['message', 'close', 'error', 'open'];

    // 拷贝选项字典
    let opts = Object.assign({}, option);

    // 定义实例字典
    let instance = {

      // socket实例
      socket: '',

      // 是否连接状态
      is_conncet: false,

      // 具体连接方法
      connect: function() {
        if(connection_url) {
          let scheme = window.location.protocol === 'https:' ? 'wss' : 'ws'
          connection_url = scheme + '://' + connection_url.split('://')[1];
          this.socket = new WebSocket(connection_url);
          this.initEvent();
        }else{
          console.log('wsurl為空');
        }
      },

      // 初始化事件
      initEvent: function() {
        for(let i = 0; i < event.length; i++){
          this.addListener(event[i]);
        }
      },

      // 判断事件
      addListener: function(event) {
        this.socket.addEventListener(event, (e) => {
          switch(event){
            case 'open':
              this.is_conncet = true;
              break;
            case 'close':
              this.is_conncet = false;
              break;
          }
          typeof opts[event] == 'function' && opts[event](e);
        });
      },

      // 发送方法，失败则回调
      send: function(data, closeCallback) {
        console.log('socket ---> ' + data)
        if(this.socket.readyState >= 2) {
          console.log('ws已经关闭');
          closeCallback && closeCallback();
        }else{
          this.socket.send(data);
        }
      }

    };

    // 调用连接方法
    instance.connect();
    return instance;
  }

index.vue

具体代码

  • x2Str方法，因为后端返回的是bytes，格式b'xxx'，编写了方法对其进行转换。

至此，实现前后端websocket通讯。