Node.js socket.setBroadcast() 方法

socket.setBroadcast()方法是 dgram 模块中 Socket 类的内置应用程序编程接口，用于设置或清除SO_BROADCAST套接字选项，帮助客户端将数据报发送到特定的广播地址。

句法：

const socket.setBroadcast( flag )

参数：此方法将布尔值作为参数，true 表示启用SO_BROADCAST套接字选项，false 表示禁用它。

返回值：此方法不返回任何值。

示例 1：文件名：index.js

Javascript

// Node.js program to demonstrate the
// socket.setBroadcast() method
  
// Importing dgram module
var dgram = require('dgram');
  
// Creating and initializing client
// and server socket
var client = dgram.createSocket("udp4");
var server = dgram.createSocket("udp4");
let broadcast_address = 12345;
  
// Catching the message event
server.on("message", function (msg) {
  
    // Displaying the client message
    process.stdout.write("UDP String: " + msg + "\n");
  
    // Exiting process
    process.exit();
})
.bind(broadcast_address, () => {
  
    // Enable the SO_BROADCAST socket option 
    // by using the setBroadcast() method
    server.setBroadcast(true);
});
  
// Client sending message to server
client.send("Hello", 0, 7, 
        broadcast_address, "localhost");

输出：

UDP String: Hello

示例 2：文件名：index.js

Javascript

// Node.js program to demonstrate the
// socket.setBroadcast() method
  
// Importing dgram module
var dgram = require('dgram');
  
// Creating and initializing client
// and server socket
var client = dgram.createSocket("udp4");
var server = dgram.createSocket("udp4");
  
// Catching the message event
server.on("message", function (msg) {
  
    // Displaying the client message
    process.stdout.write("UDP String: " + msg + "\n");
  
    // Exiting process
    process.exit();
});
  
// Catching the listening event
server.on('listening', () => {
    const address = server.address();
    console.log(`server listening 
        ${address.address}:${address.port}`);
});
  
// Binding server with port address
server.bind(1234, () => {
  
    // Enable the SO_BROADCAST socket option 
    // by using the setBroadcast() method
    server.setBroadcast(true);
});
  
// Client sending message to server
client.send("Hello", 0, 7, 1234, "localhost");

输出：

server listening 0.0.0.0:1234
UDP String: Hello

使用以下命令运行 index.js 文件：

node index.js

参考： https://nodejs.org/dist/latest-v12.x/docs/api/dgram.html#dgram_socket_setbroadcast_flag