EN
Express.js - get client IP address from request / req
4 points
In this short article, we would like to show how to get a client IP address from a request (req argument) in Express.js server application.
Steps:
- Integrate below code with your web site,
- Run your Express.js server application,
- Open one of the following addresses in the web browser:
http://localhost:3000/client-ip-addressfor localhost development,https://my-domain.com:3000/client-ip-addressfor production.
index.js file:
xxxxxxxxxx1
const express = require('express');2
3
const {getRequestIpAddress} = require('./request-utils');4
5
const port = 3000;6
const app = express();7
8
app.get('/client-ip-address', (req, res) => {9
const ip = getRequestIpAddress(req);10
response.send(`Client IP Address: ${ip}`);11
});12
13
app.listen(port, () => {14
console.log(`Server is listening at ${port} port.`);15
});
request-utils.js file:
xxxxxxxxxx1
const IP_HEADERS = [2
'Forwarded',3
'Forwarded-For',4
'X-Forwarded',5
'X-Forwarded-For', // may contain multiple IP addresses in the format: 'client IP, proxy 1 IP, proxy 2 IP' - we use first one6
'X-Client-IP',7
'X-Real-IP', // Nginx proxy, FastCGI8
'X-Cluster-Client-IP', // Rackspace LB, Riverbed Stingray9
'Proxy-Client-IP',10
'CF-Connecting-IP', // Cloudflare11
'Fastly-Client-Ip', // Fastly CDN and Firebase hosting header when forwared to a cloud function12
'True-Client-Ip', // Akamai and Cloudflare13
'WL-Proxy-Client-IP',14
'HTTP_X_FORWARDED_FOR',15
'HTTP_X_FORWARDED',16
'HTTP_X_CLUSTER_CLIENT_IP',17
'HTTP_CLIENT_IP',18
'HTTP_FORWARDED_FOR',19
'HTTP_FORWARDED',20
'HTTP_VIA',21
'REMOTE_ADDR'22
23
// you can add more matching headers here ...24
];25
26
const getRequestIpAddress = request => {27
const headers = request.headers;28
for (const header of IP_HEADERS) {29
const value = headers[header];30
if (value) {31
const parts = value.split(/\s*,\s*/g);32
return parts[0] ?? null;33
}34
}35
const client = request.connection ?? request.socket ?? request.info;36
if (client) {37
return client.remoteAddress ?? null;38
}39
return null;40
};41
42
module.exports = {43
getRequestIpAddress44
};Note:
IP_HEADERSare useful to get a client IP address when we use some other application that may cover our server, e.g.VirtualServers, load balancers, etc.
