Web Worker线程解决方案electron踩坑记录

JavaScript/前端
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2023-06-13
JavaScript迭代器与生成器使用详解
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目录
  • 初始化项目
  • 编写入口文件和 electron 插件
  • websocket
  • websocket 服务
  • 连接 websocket 服务
  • 发送心跳
  • 取消心跳
  • 重新连接
  • 其它优化
  • Worker

初始化项目

electron 开发时会遇到一对多的情况，在进行 websocket 通信时，如果接收到服务端多个指令时，而这个指令刚好需要占用线程，这个时候整个界面就会失去响应，那么我们就可以使用线程来解决这个问题.

npm create vite@latest electron-worker

执行完后修改 package.json 如下：

{
  "name": "electron-worker",
  "private": true,
  "version": ".0.0",
  "scripts": {
    "dev": "vite",
    "build": "vite build",
    "preview": "vite preview"
  },
  "dependencies": {},
  "devDependencies": {
    "@vitejs/plugin-vue": "^.2.0",
    "vite": "^.2.0",
    "vue": "^.2.41",
    "electron": ".1.4",
    "electron-builder": "^.3.3"
  }
}

编写入口文件和 electron 插件

创建 mainEntry.js 作为 electron 的入口文件，启动一个窗口

// src/main/mainEntry.js
import { app, BrowserWindow } from "electron";
process.env.ELECTRON_DISABLE_SECURITY_WARNINGS = "true";
let mainWindow;
app.whenReady().then(() => {
  let config = {
    webPreferences: {
      nodeIntegration: true,
      webSecurity: false,
      allowRunningInsecureContent: true,
      contextIsolation: false,
      webviewTag: true,
      spellcheck: false,
      disableHtmlFullscreenWindowResize: true,
    },
  };
  mainWindow = new BrowserWindow(config);
  mainWindow.webContents.openDevTools({ mode: "undocked" });
  mainWindow.loadURL(process.argv[]);
});

编写 vite 插件，在服务器启动后加载 electron 入口文件

// plugins/devPlugin.js
export const devPlugin = () => {
  return {
    name: "dev-plugin",
    configureServer(server) {
      require("esbuild").buildSync({
        entryPoints: ["./src/main/mainEntry.js"],
        bundle: true,
        platform: "node",
        outfile: "./dist/mainEntry.js",
        external: ["electron"],
      });
      server.httpServer.once("listening", () => {
        let { spawn } = require("child_process");
        let electronProcess = spawn(require("electron").toString(), ["./dist/mainEntry.js", `http://.0.0.1:${server.config.server.port}/`], {
          cwd: process.cwd(),
          stdio: "inherit",
        });
        electronProcess.on("close", () => {
          server.close();
          process.exit();
        });
      });
    },
  };
};

使用插件

import { defineConfig } from 'vite'
import vue from '@vitejs/plugin-vue'
import { devPlugin } from "./plugins/devPlugin";
export default defineConfig({
  plugins: [devPlugin(), vue()],
})

将 vue 项目文件放入和 main 同级, 结构如下所示

└─src 
    ├─main
    │      mainEntry.js  
    └─renderer
        │  App.vue
        │  main.js
        ├─assets
        └─components

修改 index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-" />
    <link rel="icon" type="image/svg+xml" href="/vite.svg" rel="external nofollow"  />
    <meta name="viewport" content="width=device-width, initial-scale=.0" />
    <title>Vite + Vue</title>
  </head>
  <body>
    <div id="app"></div>
    <script type="module" src="/src/renderer/main.js"></script>
  </body>
</html>

现在执行 npm run dev 就可以运行项目了

websocket

websocket 服务

var WebSocketServer = require('ws').Server;
var wss = new WebSocketServer({port:});
wss.on('connection', function (ws) {
  console.log('有客户端连接');
  ws.send("连接成功")
  ws.on('message', function (jsonStr) {
    console.log(jsonStr.toString());
  });
});

连接 websocket 服务

准备 Socket 对象

export default class Socket {
  websocket
  wsUrl
  constructor(wsUrl) {
    this.wsUrl = wsUrl
  }
  init() {
    if (this.websocket) return this.websocket
    const socket = this.websocket = new WebSocket(this.wsUrl)
    // WebSocket 接收服务端数据
    socket.onmessage = (e) => {
      console.log("接收服务端消息：", e.data)
    }
    // WebSocket 断开连接后触发
    socket.onclose = (e) => {}
    // WebSocket 连接成功
    socket.onopen = () => {
      console.log("连接成功")
    }
    // WebSocket 连接异常
    socket.onerror = (e) => {}
  }
}

连接 Socket

<script setup>
import Socket from './socket'
const socket = new Socket("ws://localhost:")
function register() {
  socket.init()
}
</script>
<template>
  <div>
    <button @click="register">注册</button>
  </div>
</template>
<style scoped>
</style>

点击注册后显示如下：

发送心跳

一般为了确保服务一直连接，需要客户端定时给服务发送心跳

export default class Socket {
  // ...
  heartbeatCount // 心跳次数
  heartbeatTimer // 心跳定时器
  heartbeatInterval = * 20 // 心跳发送频率(2秒一次)
  // ...
  sendHeartBeat() {
    this.heartbeatCount =
    if (this.heartbeatTimer) clearInterval(this.heartbeatTimer)
    this.heartbeatTimer = setInterval(() => {
      this.websocket.send("发送心跳")
    }, this.heartbeatInterval)
  }
}

App.vue

function sendHeartBeat() {
  socket.sendHeartBeat()
}
<button @click="sendHeartBeat">发送心跳</button>

可以看到我们在服务端日志里看到有持续心跳日志

取消心跳

因为是定时器发送，当服务端掉线后定时器却还在继续发送，现在我们来优化这个

// 断开连接
onclose() {
  console.log("已断开连接")
  this.websocket = null
  // 清除心跳定时器
  if (this.heartbeatTimer) clearInterval(this.heartbeatTimer)
}

在 socket 断开后进行调用

// WebSocket 断开连接后触发
socket.onclose = (e) => {
  this.onclose()
}

重新连接

websocket 断开有可能是客户端网络问题，所以我们需要进行尝试重连

export default class Socket {
  // ...
  socketOpen // 是否连接
  isReconnect = true // 是否可以重新连接
  reconnectCountMax = // 最大重新次数
  reconnectTimer // 重连定时器
  reconnectCurrent =  // 重连次数
  reconnectInterval // * 3 // 重连频率(3秒一次)
  // ...
  // 断开连接
  onclose() {
    console.log("已断开连接")
    this.websocket = null
    // 清除心跳定时器
    if (this.heartbeatTimer) clearInterval(this.heartbeatTimer)
    // 需要重新连接
    if (this.isReconnect) {
      this.reconnectTimer = setTimeout(() => {
        if (this.reconnectCurrent >= this.reconnectCountMax) {
          console.log("超过重连次数，重连失败")
          clearTimeout(this.reconnectTimer)
        } else {
          this.reconnectCurrent +=
          this.reconnect()
        }
      }, this.reconnectInterval)
    }
  }
  // 重新连接
  reconnect() {
    console.log("重新连接", this.reconnectCurrent)
    if (this.websocket && this.socketOpen) {
      this.websocket.close()
    }
    this.init()
  }
}

我们每三秒一次进行尝试重新连接，如果重连三次还未连接，那我们认为无法重新连接

其它优化

export enum PostMessageType {
  ON_OPEN = 'open', // websocket开启
  ON_ERROR = 'error', // websocket异常
  ON_CLOSE = 'close', // websocket关闭
  ON_MESSAGE = 'message', // websocket接收消息
  RECONNECT = 'reconnect', // websocket重新连接
  HEARTBEAT = 'heartbeat', // websocket发送心跳
  OFF = 'off', // websocket主动关闭
  REGISTER = 'register', // websocket注册成功
}
class Socket {
  wsUrl: string // 服务地址
  websocket: WebSocket | null = null // websocket对象
  socketOpen: boolean = false // socket是否开启
  heartbeatTimer: any // 心跳定时器
  heartbeatCount: number = // 心跳次数
  heartbeatInterval: number = * 20 // 心跳发送频率(2秒一次)
  isReconnect: boolean = true // 是否可以重新连接
  reconnectCountMax: number = // 最大重新次数
  reconnectCurrent: number = // 已发起重连次数
  reconnectTimer: any // 重连timer
  reconnectInterval: number = * 3 // 重连频率(3秒一次)
  constructor(url: string) {
    this.wsUrl = url
  }
  // socket 初始化
  init() {
    if (this.websocket) return this.websocket
    const socket = this.websocket = new WebSocket(this.wsUrl)
    // WebSocket 接收服务端数据
    socket.onmessage = (e) => {
      this.receive(e.data)
    }
    // WebSocket 断开连接后触发
    socket.onclose = (e) => {
      this.postMessage(PostMessageType.ON_CLOSE, e)
      this.onclose()
    }
    // WebSocket 连接成功
    socket.onopen = () => {
      this.onopen()
    }
    // WebSocket 连接异常
    socket.onerror = (e) => {
      this.postMessage(PostMessageType.ON_ERROR, e)
    }
  }
  // 连接成功后的回调
  onopen() {
    this.socketOpen = true
    this.isReconnect = true
    this.reconnectCurrent =
    this.heartbeatCount =
    this.postMessage(PostMessageType.ON_OPEN)
  }
  /**
   * 消息处理器
   * @param type
   * @param data
   */
  postMessage(type: PostMessageType, data?: any) {}
  /**
   * 断开连接
   */
  onclose() {
    this.websocket = null
    this.socketOpen = false
    // 清除心跳定时器
    clearInterval(this.heartbeatTimer)
    // 需要重新连接
    if (this.isReconnect) {
      this.reconnectTimer = setTimeout(() => {
        if (this.reconnectCurrent >= this.reconnectCountMax) {
          clearTimeout(this.reconnectTimer)
        } else {
          this.reconnectCurrent +=
          this.reconnect()
        }
      }, this.reconnectInterval)
    }
  }
  /**
   * 重新连接
   */
  reconnect() {
    this.postMessage(PostMessageType.RECONNECT, this.reconnectCurrent)
    if (this.websocket && this.socketOpen) {
      this.websocket.close()
    }
    this.init()
  }
  /**
   * 给服务端发送消息
   * @param data
   * @param callback
   */
  send(data: any, callback?: () => void) {
    const ws = this.websocket
    if (!ws) {
      this.init()
      setTimeout(() => {
        this.send(data, callback)
      },)
      return
    }
    switch (ws.readyState) {
      case ws.OPEN:
        ws.send(data)
        if (callback) {
          callback()
        }
        break
      case ws.CONNECTING:
        // 未开启，则等待s后重新调用
        setTimeout(() => {
          this.send(data, callback)
        },)
        break
      default:
        this.init()
        setTimeout(() => {
          this.send(data, callback)
        },)
    }
  }
  receive(data: any) {
    this.postMessage(PostMessageType.ON_MESSAGE, data)
  }
  /**
   * 发送心跳
   * @param data 心跳数据
   */
  sendHeartBeat(data: any) {
    this.heartbeatCount =
    if (this.heartbeatTimer) clearInterval(this.heartbeatTimer)
    this.heartbeatTimer = setInterval(() => {
      this.send(data, () => {
        this.heartbeatCount +=
        this.postMessage(PostMessageType.HEARTBEAT, { heartBeatData: data, heartbeatCount: this.heartbeatCount })
      })
    }, this.heartbeatInterval)
  }
  /**
   * 主动关闭websocket连接
   * 关闭后 websocket 关闭监听可以监听到，所以无需去额外处理
   */
  close() {
    this.isReconnect = false
    this.postMessage(PostMessageType.OFF, "主动断开websocket连接")
    this.websocket && this.websocket.close()
  }
}

上面是基础的 websocket ，具体使用需要结合业务进行继承使用

export default class SelfSocket extends Socket {
  registerData: any // 注册数据
  heartBeatData: any // 心跳数据
  constructor(url: string) {
    super(url);
  }
  initSocket(registerData: any, heartBeatData: any) {
    this.registerData = registerData
    this.heartBeatData = heartBeatData
    super.init()
  }
  onopen() {
    this.register()
    super.onopen();
  }
  /**
   * websocket 注册消息，注册成功后进行心跳发送
   */
  register() {
    this.send(this.registerData, () => {
      this.sendHeartBeat(this.heartBeatData)
      this.postMessage(PostMessageType.REGISTER, this.registerData)
    })
  }
  send(data: any, callback?: () => void) {
    // 数据加密
    const str = _encrypt(data)
    super.send(str, callback);
  }
  receive(data: any) {
    this.postMessage(PostMessageType.ON_MESSAGE, _decode(data))
  }
  postMessage(type: PostMessageType, e?: any) {}
}

我们公司 websocket 连接需要注册后进行心跳发送，且在接收和发送数据时都进行了加密和解密，简单的可以使用 base64 进行

Worker

Web Worker 使用可以参考阮一峰老师的文章，这里就不做过多介绍

创建一个 websocketWorker.js

const URL = "ws://localhost:"
import Socket from "./socket";
const ws = new Socket(URL)
self.addEventListener('message', (e) => {
  const { type, data } = e.data
  switch (type) {
    case "init":
      ws.init();
      break
    case "message":
      ws.send(data)
      break
    case "close":
      ws.close()
      break
    default:
      console.error("发送websocket命令有误")
      break
  }
})
<script setup>
import Worker from './websocketWorker?worker'
const worker = new Worker()
worker.onmessage = function (e) {
  console.log(e.data)
}
function register() {
  worker.postMessage({
    type: 'init'
  })
}
function close() {
  worker.postMessage({
    type: 'close'
  })
}
</script>
<template>
  <div>
    <button @click="register">注册</button>
    <button @click="close">关闭服务</button>
  </div>
</template>

vite 使用 worker 可以查看 worker选项

如果是 webpack 可以查看 worker-loader

module.exports = {
  chainWebpack: config => {
    config.module
      .rule('worker')
      .test(/.worker.js$/)
      .use('worker-loader')
      .loader('worker-loader')
      .options({
        inline: 'no-fallback',
      })
      .end()
    config.module.rule('js').exclude.add(/.worker.js$/)
  }
}

这里是我的配置

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