The http.server.listening is an inbuilt application programming interface of class Server within http module which is used to check if the server is listening for connection or not.
Syntax:
const server.listening
Parameters: It does not accept any argument as a parameter.
Return Value: It does not return any value.
Example 1: Filename: index.js
// Node.js program to demonstrate the
// server.listening APi
// Importing http module
const http = require('http');
// Setting up PORT
const PORT = process.env.PORT || 3000;
// Creating http Server
const 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")
Output:
Output: In-Console
server is listening Server is running at port 3000... displaying the result... displaying the result... server is closed server is closed
Now run http://localhost:3000/ in the browser.
Output: In-Browser
socket buffersize : 0
Example 2: Filename: index.js
// Node.js program to demonstrate the
// server.listening APi
// Importing http module
const 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
const 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")
Output:
Output: In-Console
server is listening Server is running at port 3000... displaying the result... displaying the result... server is closed server is closed
Now run http://localhost:3000/ in the browser.
Output: In-Browser
socket local address : ::1
Reference: https://nodejs.org/dist/latest-v12.x/docs/api/http.html#http_server_listening
