一文浅析Node中的TCP和UDP

import net from "net";

const server = net.createServer((Socket) => {
  socket.on("data", (data) => {
    console.log("监听到客户端的数据:", data.toString());
  });
  // 监听客户端断开连接事件
  socket.on("end", () => {
    console.log("客户端断开连接");
  });
  // 发送数据给客户端
  socket.end("over over over\n");
});

// 启动服务
server.listen(3000, () => {
  console.log("服务创建成功");
});

nodemon .\server.js

import net from "net";

const client = net.connect({ port: 3000 }, () => {
  client.write("今晚出去吃饭,收到请 over\n");
});
// 接收服务端的数据
client.on("data", (data) => {
  console.log("接收服务端的数据: ", data.toString());
  // 断开连接
  client.end();
});

// 断开连接
client.on("end", () => {
  console.log("断开连接");
});

function createServer(options, connectionListener) {
  return new Server(options, connectionListener);
}

function Server(options, connectionListener) {
  EventEmitter.call(this);
  // 注册连接到来时执行的回调
  if (typeof options === "function") {
    connectionListener = options;
    options = {};
    this.on("connection", connectionListener);
  } else if (options == null || typeof options === "object") {
    options = { ...options };

    if (typeof connectionListener === "function") {
      this.on("connection", connectionListener);
    }
  }
  // 服务器建立的连接数
  this._connections = 0;

  this[async_id_symbol] = -1;
  this._handle = null;
  this._usingWorkers = false;
  this._workers = [];
  this._unref = false;
  // 服务器下的所有连接是否允许半连接
  this.allowHalfOpen = options.allowHalfOpen || false;
  // 有连接时是否注册读事件
  this.pauseOnConnect = !!options.pauseOnConnect;
  this.noDelay = Boolean(options.noDelay);
  // 是否支持keepAlive
  this.keepAlive = Boolean(options.keepAlive);
  this.keepAliveInitialDelay = ~~(options.keepAliveInitialDelay / 1000);
}
ObjectSetPrototypeOf(Server.prototype, EventEmitter.prototype);
ObjectSetPrototypeOf(Server, EventEmitter);

Server.prototype.listen = function (...args) {
  
  var nORMalized = normalizeArgs(args);
  //  normalized = [{port: 9297}, null];
  var options = normalized[0];
  var cb = normalized[1];
  // 第一次listen的时候会创建，如果非空说明已经listen过
  if (this._handle) {
    throw new errors.Error("ERR_SERVER_ALREADY_LISTEN");
  }
  // listen成功后执行的回调
  var hasCallback = cb !== null;
  if (hasCallback) {
    // listen成功的回调
    this.once("listening", cb);
  }

  options = options._handle || options.handle || options;
  // 第一种情况，传进来的是一个TCP服务器，而不是需要创建一个服务器
  if (options instanceof TCP) {
    this._handle = options;
    this[async_id_symbol] = this._handle.getAsyncId();
    listenIncluster(this, null, -1, -1, backlogFromArgs);
    return this;
  }
  // 第二种，传进来一个对象，并且带了fd
  if (typeof options.fd === "number" && options.fd >= 0) {
    listenIncluster(this, null, null, null, backlogFromArgs, options.fd);
    return this;
  }
  // 创建一个tcp服务器
  var backlog;
  if (typeof options.port === "number" || typeof options.port === "string") {
    backlog = options.backlog || backlogFromArgs;
    // 第三种 启动一个TCP服务器，传了host则先进行DNS解析
    if (options.host) {
      lookupAndListen(
        this,
        options.port | 0,
        options.host,
        backlog,
        options.exclusive
      );
    } else {
      listenIncluster(
        this,
        null,
        options.port | 0,
        4,
        backlog,
        undefined,
        options.exclusive
      );
    }
    return this;
  }
};

import dgram from "node:dgram";

const server = dgram.createSocket("udp4");

server.on("error", (err) => {
  console.error(`server error:\n${err.stack}`);
  server.close();
});

server.on("message", (msg, rinfo) => {
  console.log(`server Got: ${msg} from ${rinfo.address}:${rinfo.port}`);
});

server.on("listening", () => {
  const address = server.address();
  console.log(`server listening ${address.address}:${address.port}`);
});

server.bind(3000);

import dgram from "node:dgram";
import { Buffer } from "node:buffer";

const message = Buffer.from("你个叼毛");
const client = dgram.createSocket("udp4");

client.send(message, 0, message.length, 3000, "localhost", () => {
  client.close();
});

socket.setBroadcast(flag);

import dgram from "dgram";

const server = dgram.createSocket("udp4");

server.on("message", function (msg, rinfo) {
  console.log(
    "server got: " + msg + " from " + rinfo.address + ":" + rinfo.port
  );
});

server.on("listening", function () {
  var address = server.address();
  console.log("server listening " + address.address + ":" + address.port);
});

server.bind(3000);

import dgram from "dgram";
import { Buffer } from "buffer";

const socket = dgram.createSocket("udp4");
const params = process.argv.splice(2);

socket.bind(function () {
  socket.setBroadcast(true);
});

const message = Buffer.from(...params);

socket.send(message, 0, message.length, 3000, "255.255.255.255", () => {
  socket.close();
});