Node.js socket.send()用法及代碼示例

socket.send()方法是dgram模塊中Socket類的內置應用程序編程接口，用於將消息從一個套接字發送到另一個套接字。

用法:

socket.send(msg[, offset, length][, port][, address][, callback])

參數：此方法采用以下參數：

msg:要發送的消息。
offset:消息開始處的緩衝區中的偏移量。
length:消息中的字節數。
port:目的端口。
address:目標主機名或IP地址。
callback:消息發送後調用。

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 
// server.send() method 
  
// Importing dgram module 
var dgram = require('dgram'); 
  
// Creating and initializing clinet 
// 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(); 
}) 
  
  // Binding server with port 
  .bind(1234, () => { 
  
  // Getting the reference of the server 
  // by using ref() method 
  const size = server.ref(); 
  
  // Display the result 
  console.log(size.eventNames()); 
}); 
  
// Client sending message to server 
// by using send() method 
client.send("Hello", 0, 7, 1234, "localhost");

輸出：

[ 'message' ]
UDP String:Hello

範例2： 文件名：index.js

Javascript

// Node.js program to demonstrate the 
// server.send() method 
  
// Importing dgram module 
var dgram = require('dgram'); 
  
// Creating and initializing clinet 
// 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', () => { 
  
  // Getting address information for the server 
  const address = server.address(); 
  
  // Display the result 
  console.log( 
`server listening ${address.address}:${address.port}`); 
}); 
  
  
// Binding server with port address 
// by using bind() method 
server.bind(1234, () => { 
  
  // Getting the reference of server 
  // by using ref() method 
  const size = server.ref(); 
  
  // display the result 
  console.log(size.eventNames()); 
}); 
  
// Client sending message to server 
// by using send() method 
client.send("Hello", 0, 7, 1234, "localhost", (err) =>{ 
  
  if(err) throw err; 
  console.log("message sent"); 
});

輸出：

server listening 0.0.0.0:1234
[ 'message', 'listening' ]
message sent
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_send_msg_offset_length_port_address_callback

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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.send() 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。