node . js socket . setmulticastttl()方法
原文:https://www . geesforgeks . org/node-js-socket-setmulticastttl-method/
socket.setMulticastTTL()是 dgram 模块中 socket 类的一个内置应用程序编程接口，用于设置或清除 IP_MULTICAST_TTL socket 选项，该选项有助于指定允许一个数据包通过指定多播流量的 IP 跳数。
语法:
const socket.setMulticastTTL( ttl )
参数:该方法取整数值，表示允许数据包通过指定多播流量的 IP 跳数。
返回值:此方法不返回值。
示例 1: 文件名:index.js
// Node.js program to demonstrate the
// server.setMulticastTTL() API
// 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;
// Handling 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_TTL socket option
// and specifiing the number of IP hopes
// by using the setMulticastTTL() method
server.setMulticastTTL(144);
});
// Client sending message to server
client.send("Hello", 0, 7,
broadcast_address, "localhost");
输出:
UDP String: Hello
示例 2: 文件名:
// Node.js program to demonstrate the
// server.setMulticastTTL() API
// Importing dgram module
var dgram = require('dgram');
// Creating and initializing client
// and server socket
var client = dgram.createSocket("udp4");
var server = dgram.createSocket("udp4");
// Handling the message event
server.on("message", function (msg) {
// Displaying the client message
process.stdout.write("UDP String: "
+ msg + "\n");
// Exiting process
process.exit();
});
// Handling 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_TTL socket option
// and specifiing the number of IP hopes
// by using the setMulticastTTL() method
server.setMulticastTTL(255);
});
// Client sending message to server
client.send("Hello", 0, 7,
1234, "localhost");
使用以下命令运行 index.js 文件:
node index.js
输出:
server listening 0.0.0.0:1234
UDP String: Hello
参考资料:https://nodejs . org/dist/latest-v1 . x/docs/API/dgram . html # dgram _ socket _ setmulticast _ TTL
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