node.js - How do I use the PROXY protocol to get the client's real IP address? -

aws added support elb proxy protocol, wraps tcp streams , adds client ip address (as seen proxy) backend server has access client's ip (since otherwise see elb's ip).

i know elb can run in http(s) mode, elb inserts x-forwarded-for header, run elbs in tcp mode can serve site on spdy.

how can modify node.js app (using express) use proxy protocol?

i made module caled proxywrap wraps node.js servers , automatically strips proxy protocol headers connections' streams, , resets socket.remoteaddress , socket.remoteport values found in proxy headers.

it works built-in server modules (like http, https, , net) drop-in replacement module:

var http = require('http')     , proxiedhttp = require('proxywrap').proxy(http)     , express = require('express')     , app = express()     , srv = proxiedhttp.createserver(app); // instead of http.createserver(app)  app.get('/', function(req, res) {     res.send('ip = ' + req.connection.remoteaddress + ':' + req.connection.remoteport); });  srv.listen(80); 

it works spdy module:

var proxiedspdy = require('proxywrap').proxy(require('spdy').server); 

of course, you'll have enable proxy protocol on elb (or whatever proxy app behind).