Print IP address and headers in Cloud Functions

print_ip_and_headers.js

const functions = require('firebase-functions');
const util = require('util');

exports.helloWorld = functions.https.onRequest((req, res) => {
  // For Firebase Hosting URIs, use req.headers['fastly-client-ip']
  // For callable functions, use rawRequest
  // Some users have better success with req.headers['x-appengine-user-ip']
  const ipAddress = req.headers['x-forwarded-for'] || req.connection.remoteAddress;
  const headers = JSON.stringify(req.headers, null, 2);
  const message = util.format("<pre>Hello world!\n\nYour IP address: %s\n\nRequest headers: %s</pre>", ipAddress, headers);
  res.send(message);
});

Hello world!

Your IP address: 130.211.129.169, 130.211.129.169

Request headers: {
  "host": "us-central1-xyz-xyz.cloudfunctions.net",
  "user-agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.99 Safari/537.36",
  "accept": "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8",
  "accept-language": "en-US,en;q=0.9",
  "cache-control": "no-cache, no-store",
  "fastly-client": "1",
  "fastly-client-ip": "103.228.220.xxx",
  "fastly-ff": "s48hDkrIORDrAz3sjuyh5gIWcInqIjSROZ47KAY+w/I=!MAA!cache-maa18323-MAA, s48hDkrIORDrAz3sjuyh5gIWcInqIjSROZ47KAY+w/I=!MAA!cache-maa18320-MAA",
  "fastly-orig-accept-encoding": "gzip, deflate, br",
  "fastly-ssl": "1",
  "fastly-temp-xff": "103.228.220.xxx, 103.228.220.xxx",
  "function-execution-id": "pxsrd61ahc7h",
  "pragma": "no-cache",
  "upgrade-insecure-requests": "1",
  "x-appengine-api-ticket": "22dc0a59f7506e99",
  "x-appengine-city": "?",
  "x-appengine-citylatlong": "0.000000,0.000000",
  "x-appengine-country": "US",
  "x-appengine-https": "on",
  "x-appengine-region": "?",
  "x-appengine-user-ip": "130.211.129.169",
  "x-cloud-trace-context": "ab97ae8fc4f1d6d09d7cd7b951556b09/6319039451338514513;o=1",
  "x-forwarded-for": "130.211.129.169, 130.211.129.169",
  "x-forwarded-host": "fun-api.xyz.com",
  "x-forwarded-proto": "https",
  "x-forwarded-server": "cache-maa18323-MAA",
  "x-forwarded-url": "/helloWorld",
  "x-nginx-proxy": "true",
  "x-real-ip": "157.52.84.20",
  "x-timer": "S1533821652.566928,VS0",
  "x-varnish": "2985375639, 3236888159",
  "accept-encoding": "gzip"
}

The above code is incorrect if the request is rewritten by firebase hosting. Here my actual IP is in header fastly-client-ip

It seems this has changed recently without any announcements :X

This is still working for me using:

req.headers['x-appengine-user-ip'] || req.header['x-forwarded-for'] || req.connection.remoteAddress

if callable functions, the request headers will be in context.rawRequest.
See documenation: https://firebase.google.com/docs/reference/functions/functions.https.html?authuser=0#.CallableContext

@rolandszpond, thanks for the tip

My req.header and req.headers both doesn't have anything. Can u check this please https://stackoverflow.com/questions/57104165/not-all-headers-are-shown-with-firebase-onrequest

I don't know why I have to use res.rawRequest.headers['x-forwarded-for']

2022 and Google still not published any documentation about how to get the client IP.
Increible.