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如何使用socket.io发送消息

发送消息

// 给本次连接发送消息
socket.emit()// 给某个房间内所有人发送消息
io.in(room).emit()// 除了自己以外，给某个房间的所有人发消息
socket.to(room).emit();// 除本连接外，给所有人发消息
socket.broadcast.emit();

客户端处理消息

// 发送action命令：服务端发送消息，客户端监听并执行对应的func
S: socket.emit('action');
C: socket.on('action', function(){...});// 发送一个action命令，并携带data数据
S: socket.emit('action', data);
C: socket.on('action', function(data){...});// 发送一个action命令，并携带两个数据
S: socket.emit('action', arg1, arg2);
C: socket.on('action', function(arg1, arg2){...});// 发送一个action命令，在emit方法中包含回调函数
S: socket.emit('action', data, function(arg1, arg2){...});
C: socket.on('action', function(data, fn){fn('a', 'b');});

WebRtc信令服务器原理

信令服务器的作用

具体看第九章

为什么要使用socket.io

• socket.io是websocket的超集
• socket.io有房间的概念，不需要做额外的操作
• socket.io跨平台，跨终端，跨语言

socket.io工作原理

实战

改造服务端

安装socket.io和log4js

npm install socket.io log4js

最新版本的socket.io是4.8.1，需要考虑和2版本的兼容性，很多API都变了

引入socket.io

处理connection消息

'use strict'
var http = require('http');
var https = require('https');
var fs = require('fs');var express = require('express');
var serveIndex = require('serve-index');
var app = express();
app.use(serveIndex('./public'));
app.use(express.static('./public'));// 引入socket.io
const { Server } = require('socket.io');// 引入log4js日志
var log4js = require('log4js');
log4js.configure({appenders: {file: {type: 'file',filename: 'app.log',layout: {type: 'pattern',pattern: '%r %p - %m',}}},categories: {default: {appenders: ['file'],level: 'debug'}}
});
var logger = log4js.getLogger();// http server
var http_server = http.createServer(app);
http_server.listen(8080, '0.0.0.0');var options = {key :   fs.readFileSync('/ssl/cert.key'),cert :  fs.readFileSync('/ssl/cert.pem')
}var https_server = https.createServer(options, app);
// 绑定socket.io
var io = new Server(https_server);io.sockets.on('connection', (socket)=>{console.log('客户端已连接', socket.id);socket.on('message', (room, data)=>{socket.to(room).emit('message', room, socket.id, data)//房间内所有人,除自己外});//该函数应该加锁socket.on('join', (room)=> {socket.join(room);// var myRoom = io.sockets.adapter.rooms[room]; 旧版api// var users = Object.keys(myRoom.SocketId).length;const socketIds = io.sockets.adapter.rooms.get(room); // 使用 Map 的 get 方法const users = socketIds ? socketIds.size : 0; // 处理空房间或不存在的情况logger.log('the number of user in room is: ' + users);//在这里可以控制进入房间的人数,现在一个房间最多 2个人//为了便于客户端控制，如果是多人的话，应该将目前房间里//人的个数当做数据下发下去。if(users < 3) {socket.emit('joined', room, socket.id);	if (users > 1) {socket.to(room).emit('otherjoin', room);//除自己之外}}else {socket.leave(room);socket.emit('full', room, socket.id);	}//socket.to(room).emit('joined', room, socket.id);//除自己之外//io.in(room).emit('joined', room, socket.id)//房间内所有人//socket.broadcast.emit('joined', room, socket.id);//除自己，全部站点	});socket.on('leave', (room)=> {const socketIds = io.sockets.adapter.rooms.get(room); // 使用 Map 的 get 方法const users = socketIds ? socketIds.size : 0; // 处理空房间或不存在的情况//users - 1;logger.log('the number of user in room is: ' + (users-1));socket.leave(room);socket.to(room).emit('bye', room, socket.id)//房间内所有人,除自己外socket.emit('leaved', room, socket.id);	//socket.to(room).emit('joined', room, socket.id);//除自己之外//io.in(room).emit('joined', room, socket.id)//房间内所有人//socket.broadcast.emit('joined', room, socket.id);//除自己，全部站点	});
});//connection
io.sockets.on('connection', (socket)=>{socket.on('message', (room, data)=>{socket.to(room).emit('message', room, socket.id, data)//房间内所有人});socket.on('join', (room)=> {socket.join(room);const socketIds = io.sockets.adapter.rooms.get(room); // 使用 Map 的 get 方法const users = socketIds ? socketIds.size : 0; // 处理空房间或不存在的情况logger.log('the number of user in room is: ' + users);socket.emit('joined', room, socket.id);	//socket.to(room).emit('joined', room, socket.id);//除自己之外//io.in(room).emit('joined', room, socket.id)//房间内所有人//socket.broadcast.emit('joined', room, socket.id);//除自己，全部站点	});socket.on('leave', (room)=> {const socketIds = io.sockets.adapter.rooms.get(room); // 使用 Map 的 get 方法const users = socketIds ? socketIds.size : 0; // 处理空房间或不存在的情况//users - 1;logger.log('the number of user in room is: ' + (users-1));socket.leave(room);socket.emit('leaved', room, socket.id);	//socket.to(room).emit('joined', room, socket.id);//除自己之外//io.in(room).emit('joined', room, socket.id)//房间内所有人//socket.broadcast.emit('joined', room, socket.id);//除自己，全部站点	});
});https_server.listen(443, '0.0.0.0', (err) => {if (err) {console.error('HTTPS server error: ', err);} else {console.log('HTTPS server is running on port 443');}
});

客户端实现简单的聊天室

index.html

<html><head><title>Chat Room</title><link rel="stylesheet" href="./css/main.css"></link></head><body><table align="center"><tr><td><label>UserName: </label><input type=text id="username"></input></td></tr><tr><td><label>room: </label><input type=text id="room"></input><button id="connect">Conect</button><button id="leave" disabled>Leave</button></td></tr><tr><td><label>Content: </label><br><textarea disabled style="line-height: 1.5;" id="output" rows="10" cols="100"></textarea></td></tr><tr><td><label>Input: </label><br><textarea disabled id="input" rows="3" cols="100"></textarea></td></tr><tr><td><button id="send">Send</button></td></tr></table><script src="https://cdnjs.cloudflare.com/ajax/libs/socket.io/4.8.1/socket.io.js"></script><script src="./js/client.js"></script></body></html>

client.js

'use strict'//
var userName = document.querySelector('input#username');
var inputRoom = document.querySelector('input#room');
var btnConnect = document.querySelector('button#connect');
var btnLeave = document.querySelector('button#leave');
var outputArea = document.querySelector('textarea#output');
var inputArea = document.querySelector('textarea#input');
var btnSend = document.querySelector('button#send');var socket;
var room;btnConnect.onclick = ()=>{//connectsocket = io.connect(); //recieve messagesocket.on('joined', (room, id) => {btnConnect.disabled = true;btnLeave.disabled = false;inputArea.disabled = false;btnSend.disabled = false;});	socket.on('leaved', (room, id) => {btnConnect.disabled = false;btnLeave.disabled = true;inputArea.disabled = true;btnSend.disabled = true;socket.disconnect();});	socket.on('message', (room, id, data) => {outputArea.scrollTop = outputArea.scrollHeight;//窗口总是显示最后的内容outputArea.value = outputArea.value + data + '\r';});	socket.on('disconnect', (socket)=>{btnConnect.disabled = false;btnLeave.disabled = true;inputArea.disabled = true;btnSend.disabled = true;});//send messageroom = inputRoom.value;socket.emit('join', room);
}btnSend.onclick = ()=>{var data = inputArea.value;data = userName.value + ':' + data;socket.emit('message', room, data);inputArea.value = '';
}btnLeave.onclick = ()=>{room = inputRoom.value;socket.emit('leave', room);
}inputArea.onkeypress = (event)=> {//event = event || window.event;if (event.keyCode == 13) { //回车发送消息var data = inputArea.value;data = userName.value + ':' + data;socket.emit('message', room, data);inputArea.value = '';event.preventDefault();//阻止默认行为}
}