Node.js Net Module

Node.js Utility Module

The Node.js Net module provides utilities for low-level network communication, including methods to create servers and clients. You can include this module using the following:

var net = require("net")

Methods

net.Server

net.Server is typically used to create a TCP or local server.

Events

net.Socket

The net.Socket object is an abstraction of a TCP or UNIX socket. net.Socket instances implement a duplex stream interface. They can be created by the user and used as a client (with connect()), or they can be created by Node.js and passed to the user through the connection event of a server.

Events

Events of net.Socket include:

Properties

net.Socket provides several properties to interact with the socket:

Methods

Example

Create a server.js file with the following code:

var net = require('net');
var server = net.createServer(function(connection) { 
   console.log('client connected');
   connection.on('end', function() {
      console.log('client closed the connection');
   });
   connection.write('Hello World!\r\n');
   connection.pipe(connection);
});
server.listen(8080, function() { 
  console.log('server is listening');
});

Run the server code:

$ node server.js
server is listening   # Server is created and listening on port 8080

Open a new terminal window and create a client.js file with the following code:

var net = require('net');
var client = new net.Socket();
client.connect(8080, '127.0.0.1', function() {
   console.log('Connected');
   client.write('Hello from client');
});
client.on('data', function(data) {
   console.log('Received: ' + data);
   client.destroy(); // kill client after server's response
});
client.on('close', function() {
   console.log('Connection closed');
});

Run the client code:

$ node client.js
Connected
Received: Hello World!
Connection closed

var net = require('net');
var client = net.connect({port: 8080}, function() {
   console.log('Connected to the server!');  
});
client.on('data', function(data) {
   console.log(data.toString());
   client.end();
});
client.on('end', function() { 
   console.log('Disconnected from the server');
});

Executing the above client code:

Connected to the server!
Hello World!

Disconnected from the server

Gif Demonstration

Node.js Utility Modules