Getting the Domain Info for Request in Express.js

We need to get the DNS information to track the address from where we receive the requests. This feature also provides an added layer of security, protecting the application from different type of DOS and DDOS attacks.

We can use the following functions to get the domain and host information.

Syntax

• Getting the origin info:

var origin = req.get('origin');

• Getting the host info:

var host = req.get('host');

Example 1

Create a file with the name "dnsInfo.js" and copy the following code snippet. After creating the file, use the command "node dnsInfo.js" to run this code as shown in the example below −

// Getting the Host info Demo Example
// Importing the express module
var express = require('express');

// Initializing the express and port number
var app = express();
var PORT = 3000;

// Creating a GET Api endpoint
app.get("/route", (req, res) => {
   var host = req.get('host');
   console.log(host)
   var origin = req.get('origin');
   console.log(origin)
})
app.listen(PORT, function(err){
   if (err) console.log(err);
   console.log("Server listening on PORT", PORT);
});

Output

Hit the following URL with a GET request: localhost:3000/route

C:\home\node>> node dnsInfo.js
Server listening on PORT 3000
localhost:3000
undefined

Example 2

Let's take a look at one more example.

// Getting the Host info Demo Example
// Importing the express module
var express = require('express');

// Initializing the express and port number
var app = express();
var PORT = 3000;

// Creating a GET Api endpoint
app.get("/route", (req, res) => {
   var host = req.get('host');
   console.log("Host: ", host)
   var origin = req.get('origin');
   console.log("Origin: ", origin)
   var userIP = req.socket.remoteAddress;
   console.log("UserIp: ", userIP)
   res.send("DNS host" + host +" origin: " + origin +" userIP : "+ userIP)
})
app.listen(PORT, function(err){
   if (err) console.log(err);
   console.log("Server listening on PORT", PORT);
});

Output

C:\home\node>> node dnsInfo.js
Server listening on PORT 3000
Host: localhost:3000
Origin: undefined
UserIp: ::ffff:127.0.0.1