Node.js socket.setMulticastLoopback()用法及代碼示例

socket.setMulticastLoopback()方法是dgram模塊中Socket類的內置應用程序編程接口，用於設置或清除IP_MULTICAST_LOOP套接字選項，該選項有助於服務器在本地接口接收多播數據包。

用法:

const socket.setBroadcast( flag )

參數：此方法將布爾值作為參數，以啟用IP_MULTICAST_LOOP套接字選項為true，以false禁用它為參數。

返回值：此方法不返回任何值。

範例1： 文件名：index.js

Javascript

// Node.js program to demonstrate the 
// socket.setMulticastLoopback() 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 IP_MULTICAST_LOOP socket option  
    // by using the setMulticastLoopback() method 
    server.setMulticastLoopback(true); 
}); 
  
// Client sending message to server 
client.send("Hello", 0, 7,  
    broadcast_address, "localhost");

輸出：

UDP String:Hello

範例2： 文件名：index.js

Javascript

// Node.js program to demonstrate the 
// socket.setMulticastLoopback() 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(); 
}); 
  
// Cathing 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 IP_MULTICAST_LOOP socket option  
    // by using the setMulticastLoopback() method 
    server.setMulticastLoopback(true); 
}); 
  
// Client sending message to server 
client.send("Hello", 0, 7, 1234, "localhost");

輸出：

server listening 0.0.0.0:1234
UDP String:Hello

使用以下命令運行index.js文件：

node index.js

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

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注：本文由純淨天空篩選整理自RohitPrasad3大神的英文原創作品 Node.js socket.setMulticastLoopback() Method。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。