socket.bind([port][, address][, callback])

• port <integer>
• address <string>
• callback <Function> 没有参数。 当绑定完成时调用。

对于 UDP 套接字，使 dgram.Socket 在命名的 port 和可选的 address 上监听数据报消息。 如果未指定 port 或 0，则操作系统将尝试绑定到随机端口。 如果未指定 address，则操作系统将尝试监听所有地址。 一旦绑定完成，则会触发 'listening' 事件并调用可选的 callback 函数。

同时指定 'listening' 事件监听器并将 callback 传给 socket.bind() 方法无害但不是很有用。

绑定的数据报套接字使 Node.js 进程保持运行以接收数据报消息。

如果绑定失败，则生成 'error' 事件。 在极少数情况下（例如，尝试与关闭的套接字绑定），可能会抛出 Error。

UDP 服务器监听端口 41234 的示例：

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(41234);
// 打印: server listening 0.0.0.0:41234const dgram = require('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(41234);
// 打印: server listening 0.0.0.0:41234

• port <integer>
• address <string>
• callback <Function> with no parameters. Called when binding is complete.

For UDP sockets, causes the dgram.Socket to listen for datagram messages on a named port and optional address. If port is not specified or is 0, the operating system will attempt to bind to a random port. If address is not specified, the operating system will attempt to listen on all addresses. Once binding is complete, a 'listening' event is emitted and the optional callback function is called.

Specifying both a 'listening' event listener and passing a callback to the socket.bind() method is not harmful but not very useful.

A bound datagram socket keeps the Node.js process running to receive datagram messages.

If binding fails, an 'error' event is generated. In rare case (e.g. attempting to bind with a closed socket), an Error may be thrown.

Example of a UDP server listening on port 41234:

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(41234);
// Prints: server listening 0.0.0.0:41234const dgram = require('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(41234);
// Prints: server listening 0.0.0.0:41234