Node.js dgram.createSocket() Method

The dgram.createSocket() method is an inbuilt application programming interface within dgram module which is used to create the dgram.socket object.

Syntax:

const dgram.createSocket(options[, callback])

Parameters: This method takes the following parameter:

• options: It will use one of the following options- 
  • type: The family of sockets.
  • reuseAddr: Boolean value if the address has been reused.
  • ipv6Only: Setting ipv6Only to true will disable dual-stack support.
  • recvBufferSize: Sets the SO_RCVBUF socket value.
  • sendBufferSize: Sets the SO_SNDBUF socket value.
  • lookup: Custom lookup function.
• callback: callback function for further operation.

Return Value: This method returns the object of dgram.socket.

Example 1: In this example, we will see the use of dgram.createSocket() Method

Filename: index.js

Javascript

// Node.js program to demonstrate the
// dgram.createSocket() method

// importing dgram module
const dgram = require('dgram');

// Creating and initializing client
// and server socket by using
// createSocket() method
let client = dgram.createSocket("udp4");
let server = dgram.createSocket("udp4");

// Catching the message event
server.on("message", function (msg) {

    // Displaying the client message
    process.stdout.write("UDP String: " + msg + "\n");

    // Exiting process
    process.exit();
})
    // Binding server with port
    .bind(1234, () => {

        // Setting the Send buffer size
        // by using setSendBufferSize() method
        server.setSendBufferSize(12345);

        // Getting the receive buffer size
        // by using getSendBufferSize() method
        const size = server.getSendBufferSize();

        // Display the result
        console.log(size);

    });

// Client sending message to server
client.send("Hello", 0, 7, 1234, "localhost");

Output:

12345
UDP String: Hello

Example 2: In this example, we will see the use of dgram.createSocket() Method

Filename: index.js

Javascript

// Node.js program to demonstrate the
// dgram.createSocket() method

// Importing dgram module
const dgram = require('dgram');

// Creating and initializing client
// and server socket by using
// createSocket() method
let client = dgram.createSocket("udp4", () => {
    console.log("client is created");
});
let server = dgram.createSocket("udp4", () => {
    console.log("server is created");
});

// Catching the message event
server.on("message", function (msg) {

    // Displaying the client message
    process.stdout.write("UDP String: " + msg + "\n");

    // Exiting process
    process.exit();

});

// Catching the listening event
server.on('listening', () => {

    // Getting address information
    // for the server
    const address = server.address();

    // Display the result
    console.log(`server listening
    ${address.address}:${address.port}`);

});

// Binding server with port address
// by using bind() method
server.bind(1234, () => {

    // Setting the Send buffer size
    // by using setSendBufferSize() method
    server.setSendBufferSize(1234567);

    // Getting the Send buffer size
    // by using getSendBufferSize() method
    const size = server.getSendBufferSize();

    // Display the result
    console.log(size);
});

// Client sending message to server
client.send("Hello", 0, 7, 1234, "localhost");

Output:

server listening 0.0.0.0:1234
1234567
server is created
UDP String: Hello

Run the index.js file using the following command:

node index.js

Reference: https://nodejs.org/dist/latest-v12.x/docs/api/dgram.html#dgram_dgram_createsocket_options_callback