Node.js process.send()用法及代碼示例

process.send()方法是流程模塊的內置應用程序編程接口，子流程用於與父流程進行通信。此方法不適用於根進程，因為它沒有任何父進程。

用法:

process.send(message, [sendHandle])

參數：此方法接受以下參數：

message:必須發送的消息。
sendHandle:套接字或服務器對象。它是一個可選參數。

返回值：布爾值。如果郵件發送成功，則返回true，否則返回false。

範例1：首先，在Parent.js中，我們產生子進程。然後開始收聽子進程。在Child.js中，我們在Child.js中獲得消息。然後，我們檢查send方法是否可用，然後使用process.send()向父級發送一條消息。

Parent.js


// Require fork method from child_process 
// to spawn child process
const fork = require('child_process').fork;
  
// Child process file
const child_file = 'Child.js';
  
// Spawn child process
const child = fork(child_file);
  
// Start listening to the child process
child.on('message', message => {
  
    // Message from the child process
    console.log('Message from child:', message);
});

Child.js


console.log('In Child.js')
  
// If the send method is available
if(process.send) {
  
    // Send Hello
    process.send("Hello, this is child process.");
}

使用以下命令運行Parent.js文件：

node Parent.js

輸出：

In Child.js
Message from child:Hello, this is child process.

範例2：來自子進程的多條消息。

Parent.js


// Require fork method from child_process 
// to spawn child process
const fork = require('child_process').fork;
  
// Child process file
const child_file = 'Child.js';
  
// Spawn child process
const child = fork(child_file);
  
// Start listening to the child process
child.on('message', message => {
  
    // Message from the child process
    console.log('Message from child:', message);
});

Child.js


console.log('In Child.js')
  
// If the send method is available
if(process.send) {
  
    // Send Hello
    process.send("Hello, this is child process.");
  
    // Send multiple messages
    setTimeout((function() {
        return process.send("This was send after 1 second.");
    }), 1000);
  
    setTimeout((function() {
        return process.send("This was send after 2 seconds.");
    }), 2000);
  
    setTimeout((function() {
        return process.send("This was send after 3 seconds.");
    }), 3000); 
}

使用以下命令運行Parent.js文件：

node Parent.js

輸出：

In Child.js
Message from child:Hello, this is child process.
Message from child:This was sent after 1 second.
Message from child:This was sent after 2 seconds.
Message from child:This was sent after 3 seconds.

參考： https://nodejs.org/api/process.html#process_process_send_message_sendhandle_options_callback

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注：本文由純淨天空篩選整理自adityapande88大神的英文原創作品 Node.js process.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。