Node.js http.server.listening 属性

http.server.listening是 http 模块中的 Server 类的内置应用程序编程接口，用于检查服务器是否正在侦听连接。

句法：

const server.listening

参数：它不接受任何参数作为参数。

返回值：它不返回任何值。

示例 1：文件名：index.js

Javascript

// Node.js program to demonstrate the  
// server.listening APi
    
// Importing http module 
var http = require('http'); 
    
// Setting up PORT 
const PORT = process.env.PORT || 3000; 
    
// Creating http Server 
var httpServer = http.createServer(
  function(request, response){ 
  
  // getting the reference of the 
  // underlying socket object
  // by using socket API
  const value = response.socket;
    
  // display result
  // by using end() api
  response.end( "socket buffersize : " 
  + value.bufferSize, 'utf8', () => { 
      console.log("displaying the result..."); 
  
      // closing server 
      // by using close() api
      httpServer.close(()=>{
          console.log("server is closed")
      })
  }); 
}); 
    
// Listening to http Server 
// by using listen() api
httpServer.listen(PORT, () => { 
    console.log("Server is running at port 3000..."); 
});
  
// checking if the server is listening or not
if(httpServer.listening)
console.log("server is listening")
else
console.log("server is not listening")

输出：

输出：控制台内

server is listening
Server is running at port 3000...
displaying the result...
displaying the result...
server is closed
server is closed

现在在浏览器中运行 http://localhost:3000/。

输出：浏览器内

socket buffersize : 0

示例 2：文件名：index.js

Javascript

// Node.js program to demonstrate the  
// server.listening APi
    
// Importing http module 
var http = require('http'); 
  
// Request and response handler 
const http2Handlers = (request, response) => { 
    
  // getting the reference of the
  // underlying socket object
  // by using socket API
  const value = response.socket;
    
  // display result
  // by using end() api
  response.end( "socket local address : " 
  + value.localAddress, 'utf8', () => { 
      console.log("displaying the result..."); 
  
      // closing server 
      // by using close() api
      httpServer.close(()=>{
          console.log("server is closed")
      })
  });
  }; 
    
// Listening to http Server 
// by using listen() api
var httpServer = http.createServer(
    http2Handlers).listen(3000, () => { 
    console.log("Server is running at port 3000..."); 
}); 
  
// checking if the server is listening or not
if(httpServer.listening)
console.log("server is listening")
else
console.log("server is not listening")

输出：

输出：控制台内

server is listening
Server is running at port 3000...
displaying the result...
displaying the result...
server is closed
server is closed

现在在浏览器中运行 http://localhost:3000/。

输出：浏览器内

socket local address : ::1

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