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1. TCP服务搭建

1.1 socket

先来粗略了解下socket

套接字（socket）是一个抽象层，应用程序可以通过它发送或接收数据，可对其进行像对文件一样的打开、读写和关闭等操作。套接字允许应用程序将I/O插入到网络中，并与网络中的其他应用程序进行通信。网络套接字是IP地址与端口的组合。 (摘自百度百科)

socket用于在两个基于TCP/IP协议的应用程序之间相互通信.最早出现在UNIX系统中,是UNIX系统主要的信息传递方式.在windows系统中，socket称为winsock.

两种形式的socket：流式套接字,对应与TCP协议.
数据报套接字,对应与UDP协议.

2.创建TCP服务端

server.js(服务端)

const net = require("net");
const sever = net.createServer();
// const clients = [];
const users = [];
const types = require("./types");
sever.on("connection", clientSocket => {console.log("有连接进来,请注意```");// clients.push(clientSocket)clientSocket.on("data", data => {console.log("监听data事件,有人说:", data.toString());data = JSON.parse(data.toString().trim());switch (data.type) {case types.login:if (users.find(item => item.nickName === data.nickName)) {return clientSocket.write(JSON.stringify({type: types.login,success: false,message: "昵称已存在"}));}clientSocket.nickName = data.nickName;users.push(clientSocket);clientSocket.write(JSON.stringify({type: types.login,success: true,message: "登录成功",nickName:data.nickName,sumUsers: users.length}));users.forEach(user=>{if(user!==clientSocket){user.write(JSON.stringify({type:types.log,message:`${data,nickName} 进入聊天室,当前在线用户数${user.length}`}))}})break;// 群聊天case types.broadcast:users.forEach(item => {item.write(JSON.stringify({type:types.broadcast,message:data.message,nickName:clientSocket.nickName}))})break;// 点对点case types.p2p:const user = users.find(item => item.nickName === data.nickName)if(!user){return clientSocket.write(JSON.stringify({type:types.p2p,success:false,message:"该用户不存在"}))}console.log('clientSocket.nickName',clientSocket.nickName)user.write(JSON.stringify({type:types.p2p,message:data.message,nickName:clientSocket.nickName,success:true}))break;default:break;}});// 离线clientSocket.on("end",()=>{console.log("有用户离线了~~~")const index =users.findIndex(user => user.nickName === clientSocket.nickName)if(index !== -1){const offlineUser = users[inde]users.splice(index,1)users.forEach(user=>{if(user!==clientSocket){user.write(JSON.stringify({type:types.log,message:`${offlineUser,nickName} 离开了聊天室,当前在线用户数${user.length}`}))}})}})// clientSocket.write('hello,返回的是buffer,用tostring转一下哦')
});sever.listen(2000, () => {console.log("server running  127.0.0.1 2000");
});

3.创建客户端

client.js(客户端)

const net = require("net");
const types = require("./types");
let nickName = null;
const client = net.createConnection({host: "127.0.0.1",port: 2000
});client.on("connect", () => {console.log("连接成功了~~~");process.stdout.write("请输入昵称:");// 连接完毕后,可以监听终端的信息,发给服务端process.stdin.on("data", data => {data = data.toString().trim();console.log("nickName", nickName);if (!nickName) {client.write(JSON.stringify({type: types.login,nickName: data}));}const matches = /^@(\w+)\s(.+)$/.exec(data);if (matches) {//符合 @xxx xxx  格式return client.write(JSON.stringify({type: types.p2p,nickName: matches[1],message: matches[2]}));}//群聊天client.write(JSON.stringify({type: types.broadcast,message: data}));});
});client.on("data", data => {// console.log("服务端发来的data:::", data.toString());data = JSON.parse(data.toString().trim());switch (data.type) {case types.login:if (!data.success) {console.log("登录失败", `${data.message}`);process.stdout.write("请输入昵称");} else {process.stdout.write("登录成功,当前在线人数:", data.sumUsers);nickName = data.nickName;}break;case types.broadcast:console.log(`${data.nickName}:${data.message}`);break;case types.p2p:if (!data.success) {return console.log(`发送失败:${data.message}`);}console.log(`${data.nickName}对你说:${data.message}`);break;case types.log:console.log(`${data.message}`);break;default:console.log("未知消息类型哦~");break;}
});

types.js

module.exports = {login: 0,broadcast: 1,p2p: 2,log: 3
};

总结

• 通过net模块建立TCP服务
• TCP必须建立连接(3次握手)后才能通信
• socket通信模型
• 和使用其他node模块(如koa)一样的思路,都是先建立服务(server),指定端口号