Websocket 客户端覆盖彼此的连接

问题描述

我正在尝试使用 Nodejs express 服务器和 LitComponent-Client 实现服务器-客户端示例。运行 1:1 配置时，服务器和客户端之间的通信工作完美。当启动第二个客户端时，数据传输停止工作，只有新客户端接收数据。

所有客户端都在 localhost:3001 上运行 - 服务器在 localhost:3000 上运行。

如何向多个客户端持续发送数据？

客户

import short from 'short-uuid';
import { io } from 'socket.io-client';

...

constructor() {
    super();

    //Generate app id
    this.app_id = short.generate();
    console.log('# app-id: ' + this.app_id);

    this.socket = io('ws://localhost:3000',{ forceNew: true });

    this.socket.on('connect',() => {
      this.socket.emit('log','app-id: ' + this.app_id);
    });

    this.socket.on('data',message => {
      this.receiveData(message);
    });

    this.socket.on('disconnect',function () {
      console.log('# Socket disconnected');
    });
  }

...

服务器

var app = require("express")();
const express = require("express");

var http = require("http").createServer(app);
var io = require("socket.io")(http,{
    cors: {
        origin: "http://localhost:3001",methods: ["GET","POST"],},});

let connectCounter = 0;

let sock;
io.on("connect",(socket) => {
    sock = socket;
    console.log("# " + socket.id + " | ■ App connected");
    connectCounter++;
    console.log("# New connection - Now have " + connectCounter);
    socket.on("disconnect",() => {
        connectCounter--;
        console.log("# Lost connection - Now have " + connectCounter);
    });
    socket.on("log",(message) => {
        console.log("# " + socket.id + " | " + message);
    });
});

function sendData(msg) {
    sock.emit("data",msg);
}

...

http.listen(3000,() => {
    console.log("# HTTP: listening on *:3000");
});

解决方法

在服务器端：

let sock;
io.on("connect",(socket) => {
    sock = socket;
    ...
});

function sendData(msg) {
    sock.emit("data",msg);
}

你能看出这里有什么问题吗？每次新用户连接时，您都将他设置为全局 sock，然后您只发送到该套接字。相反，您需要的是将所有套接字保留在某个集合中，如下所示：

let sockets = {};

io.on("connect",(socket) => {
    sockets[socket.id] = socket;
    ...
    socket.on("disconnect",() => {
        ...
        delete sockets[socket.id];
    });
});

function sendData(msg) {
    for (var socket_id in sockets) {
        sockets[socket_id].emit("data",msg);
    }
}

AFAIK socket.io 已经为你做了，但我不记得具体的属性（自从我处理 socket.io 已经有一段时间了），所以你必须阅读 api。