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Express.js – Getting Remote Client Address
An application needs to maintain the remote client address for managing the number of requests from a computer system and tracking its usage. But sometimes, the server runs behind an NGINX server, so we need to check its forward request. For this purpose, we can use "x-forwarded-for"
Syntax
req.headers['x-forwarded-for'] || req.socket.remoteAddress
If the proxy isn't yours, one should be careful while using the x-forwarded-for header, because it can be spoofed.
Example 1
Create a file with the name "remoteAddress.js" and copy the following code snippet. After creating the file, use the command "node remoteAddress.js" to run this code as shown in the example below −
// req.query() Demo Example
// Importing the express module
var express = require('express');
// Initializing the express and port number
var app = express();
var PORT = 3000;
// Getting the request query string
app.get('/api', function(req, res){
console.log('id: ' + req.query.id)
res.send('id: ' + req.query.id);
});
// Listening to the port
app.listen(PORT, function(err){
if (err) console.log(err);
console.log("Server listening on PORT", PORT);
});Hit a Get Request at the following endpoint - http://localhost:3000/
Output
C:\home
ode>> node remoteAddress.js Server listening on PORT 3000 IP Address: ::ffff:127.0.0.1
Example 2
Let's take a look at one more example.
// express.raw() Demo Example
// Importing the express module
var express = require('express');
// Initializing the express and port number
var app = express();
var PORT = 3000;
app.get('/api*', function (req, res){
var ip = req.headers['x-forwarded-for'] || req.socket.remoteAddress
console.log('IP Address: ' + ip)
});
// Listening to the port
app.listen(PORT, function(err){
if (err) console.log(err);
console.log("Server listening on PORT", PORT);
});
app.get('/', function (req, res){
var forwardedIpsStr = req.header('x-forwarded-for');
var IP = '';
if (forwardedIpsStr) {
IP = forwardedIps = forwardedIpsStr.split(',')[0];
}
});Hit a Get Request for any of the following endpoints –
http://localhost:3000/api http://localhost:3000/api/v2 http://localhost:3000/api/v3 and so on...
It will compare all the endpoints with /api and track it.
Output
C:\home
ode>> node remoteAddress.js Server listening on PORT 3000 IP Address: ::ffff:127.0.0.1 IP Address: ::ffff:127.0.0.1 IP Address: ::ffff:127.0.0.1
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