The http.server.listen() is an inbuilt application programming interface of the class Server within the HTTP module which is used to start the server by accepting new connections.
Syntax:
const server.listen(options[, callback])
Parameters: This method accepts the following two parameters:
- option: It can be the port, host, path, backlog, exclusive, readableAll, writableAll, ipv6Only, etc depending upon user need.
- callback: It is an optional parameter, it is the callback function that is passed as a parameter.
Return Value: This method returns nothing but a callback function.
Example 1: Filename-index.js
// Node.js program to demonstrate the // server.listen() method // Importing http module var 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 method
const value = response.socket;
// Display result
// by using end() method
response.end( "socket buffersize : "
+ value.bufferSize, 'utf8' , () => {
console.log( "displaying the result..." );
// Closing server
// by using close() method
httpServer.close(() => {
console.log( "server is closed" )
})
});
});
// Listening to http Server // by using listen() method httpServer.listen(PORT, () => { console.log( "Server is running at port 3000..." );
}); |
Run the index.js file using the following command:
node index.js
Output:
Server is running at port 3000... displaying the result... server is closed
Now run http://localhost:3000/ in the browser and you will see the following output on screen:
socket buffersize : 0
Example 2: Filename-index.js
// Node.js program to demonstrate the // server.listen() method // Importing http module const http = require( 'http' );
// Request and response handler const httpHandlers = (request, response) => { // Getting the reference of the
// underlying socket object
// by using socket method
const value = response.socket;
// Display result by using end() method
response.end( "socket local address : "
+ value.localAddress, 'utf8' , () => {
console.log( "displaying the result..." );
// Closing server by using close() method
httpServer.close(() => {
console.log( "server is closed" )
})
});
}; // Listening to http Server // by using listen() method const httpServer = http.createServer( httpHandlers).listen(3000, () => {
console.log( "Server is running at port 3000..." );
});
|
Run the index.js file using the following command:
node index.js
Output:
Server is running at port 3000... displaying the result... server is closed
Now run http://localhost:3000/ in the browser and you will see the following output on the screen:
socket local address : ::1
Reference: https://nodejs.org/dist/latest-v12.x/docs/api/http.html#http_server_listen