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

socket.gif

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/<job_name>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/<str:job_name>', 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/<str: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。
<template>
        <div>

                <el-button type="primary" @click="runFunction" >执行</el-button>
                <el-button type="primary"  @click="connectWebSock" >显示</el-button>

    <div class="socketView">
      <span v-for="i in socketMessage" :key="i">{{i}}</span>
    </div>
  </div>
</template>
<script>
  import R from '@/plugins/axios';
  import ws from '@/plugins/socket'
  export default {
    data() {
      return {
        webSocket: '',
        socketMessage: [],
      }
    },

        methods: {
          // 打开连接的处理
      openSocket(e) {
        if (e.isTrusted) {
          const h = this.$createElement;
          this.$notify({
            title: '提示',
            message: h('i', { style: 'color: teal'}, '已建立Socket连接')
          });
        }
      },

    // 连接时的处理
    listenSocket(e) {
      if (e.data){
        this.socketMessage.push(this.x2Str(e.data))
      }
    },

    // 连接webSocket
                connectWebSock() {
      let wsuri = process.env.BACKEND_URL + '/ws/job/' + this.selectFunctions
      this.webSocket = ws(wsuri, {
        open: e => this.openSocket(e),
        message: e => this.listenSocket(e),
        close: e => this.closeSocket(e)
      })
    },

          // 转码
    x2Str(str) {
      if (str) {
        let reg = new RegExp("(?<=^b').*(?='$)")
        let result = str.replace(/(?:\\x[\da-fA-F]{2})+/g, m =>
          decodeURIComponent(m.replace(/\\x/g, '%'))
        )
        return reg.exec(result)[0]
      }
    },

    // 执行方法
    runFunction() {
      R.myRequest('GET','api/start_job/' + this.selectFunctions, {}, {}).then((response) => {
        if (response.hasOwnProperty('response')){
            this.$message({
            type: 'error',
            message: '服务端返回错误,返回码:' + response.response.status 
            });
        }; 
        if (response.data == 'ok') {
            this.$message({
              type: 'success',
              message: '开始执行[' + this.selectFunctions + ']'
            });
        }
      });
    }      
    }
}
</script>

至此,实现前后端websocket通讯。