Node.js UDP / Datagram Sockets模块

• UDP / Datagram Sockets
  
  • Class: dgram.Socket
    
    • Event: ‘close’
    • Event: ‘error’
    • Event: ‘listening’
    • Event: ‘message’
    • socket.addMembership(multicastAddress[, multicastInterface])
    • socket.address()
    • socket.bind([port][, address][, callback])
    • socket.bind(options[, callback])
    • socket.close([callback])
    • socket.dropMembership(multicastAddress[, multicastInterface])
    • socket.send(msg, [offset, length,] port, address[, callback])
    • socket.setBroadcast(flag)
    • socket.setMulticastLoopback(flag)
    • socket.setMulticastTTL(ttl)
    • socket.setTTL(ttl)
    • socket.ref()
    • socket.unref()
    • Change to asynchronous socket.bind() behavior
  • dgram module functions
    
    • dgram.createSocket(options[, callback])
    • dgram.createSocket(type[, callback])

The dgram module provides an implementation of UDP Datagram sockets.

dgram模块提供了一个UDP数据报文套接字的实现。

const dgram = require('dgram');
const server = dgram.createSocket('udp4');

server.on('error', (err) => {
  console.log(`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', () => {
  var address = server.address();
  console.log(`server listening ${address.address}:${address.port}`);
});

server.bind(41234);
// server listening 0.0.0.0:41234

Class: dgram.Socket

Added in: v0.1.99
The dgram.Socket object is an EventEmitter that encapsulates the datagram functionality.

New instances of dgram.Socket are created using dgram.createSocket(). The new keyword is not to be used to create dgram.Socket instances.

dgram.Socket对象是一个事件发生器，囊括了数据报文的功能。

dgram.Socket实例使用dgram.createSocket()来创建。这个新的关键字不能被用来创建dgram.Socket实例。

Event: ‘close’

Added in: v0.1.99
The ‘close’ event is emitted after a socket is closed with close(). Once triggered, no new ‘message’ events will be emitted on this socket.

当套接字被关闭后会触发’close’事件。一旦触发该事件，在该套接字上就不会有新的’message’ 事件被触发了。

Event: ‘error’

Added in: v0.1.99

• exception

The ‘error’ event is emitted whenever any error occurs. The event handler function is passed a single Error object.

任何错误产生时都会触发’error’事件。事件处理函数只会传递一个错误对象。

Event: ‘listening’

Added in: v0.1.99
The ‘listening’ event is emitted whenever a socket begins listening for datagram messages. This occurs as soon as UDP sockets are created.

当套接字开始监听数据报报文时，’listening’事件就会被触发。一旦UDP套接字被创建就会发生该事件。

Event: ‘message’

Added in: v0.1.99

• msg - The message
• rinfo