go get github.com/sebest/xff

package main

import (
  "net/http"

  "github.com/sebest/xff"
)

func main() {
  handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
    w.Write([]byte("hello from " + r.RemoteAddr + "\n"))
  })

  xffmw, _ := xff.Default()
  http.ListenAndServe(":8080", xffmw.Handler(handler))
}

go run server.go

$ curl -D - -H 'X-Forwarded-For: 42.42.42.42' http://localhost:8080/
HTTP/1.1 200 OK
Date: Fri, 20 Feb 2015 20:03:02 GMT
Content-Length: 29
Content-Type: text/plain; charset=utf-8

hello from 42.42.42.42:52661

Stargazers

Forkers

rs lukehandle mapix cinderalla imjerrybao maxbaldin cloudxtreme adamjacobmuller yinlei ijt etsangsplk stanhu packethost wongnai sreekanth370 cfunkhouser junxie6 isgasho standardgalactic akahn ajunlonglive proxeter viru-tech

func getIPAdress(r *http.Request) string {
    for _, h := range []string{"X-Forwarded-For", "X-Real-Ip"} {
        addresses := strings.Split(r.Header.Get(h), ",")
        // march from right to left until we get a public address
        // that will be the address right before our proxy.
        for i := len(addresses) -1 ; i >= 0; i-- {
            ip := addresses[i]
            // header can contain spaces too, strip those out.
            realIP := net.ParseIP(strings.Replace(ip, " ", "", -1))
            if !realIP.IsGlobalUnicast() && !isPrivateSubnet(realIP) {
                // bad address, go to next
                continue
            }
            return ip
        }
    }
    return ""
}