package main

import (
	"fmt"
	"log"
	"net/http"
	"net/url"
	"time"

	"github.com/zenazn/goji"
)

func ping(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/javascript")
	fmt.Fprintf(w, "(function(){})();")

	referrer := r.Referer()
	if referrer == "" {
		return
	}

	url, err := url.Parse(referrer)

	if err != nil {
		http.Error(w, "Couldn't parse "+referrer+": "+err.Error(), 500)
		return
	}

	var ip string
    if res := r.Header.Get("X-Forwarded-For"); res != "" {
		ip = res
		log.Println("Fetching IP from proxy: ", ip)
	} else {
		ip = r.RemoteAddr
	}

	visit := &Visit{
		IP:        ip,
		Host:      url.Host,
		Path:      url.Path,
		CreatedAt: time.Now().UTC().Format(time.RFC3339),
	}
	log.Println("Logging visit:", visit.String())

	err = visit.Save()

	if err != nil {
		http.Error(w, err.Error(), 500)
		return
	}
}

func main() {
	goji.Get("/ping", ping)
	goji.Get("/ping.js", ping)
	goji.Serve()
}

package main

import (
	"fmt"
	"log"
	"net/http"
	"net/url"
	"time"

	"github.com/zenazn/goji"
)

func ping(w http.ResponseWriter, r *http.Request) {
	fmt.Fprintf(w, "")

	referrer := r.Referer()
	if referrer == "" {
		return
	}

	url, err := url.Parse(referrer)

	if err != nil {
		http.Error(w, "Couldn't parse "+referrer+": "+err.Error(), 500)
		return
	}

	var ip string
    if res := r.Header.Get("X-Forwarded-For"); res != "" {
		ip = res
		log.Println("Fetching IP from proxy: ", ip)
	} else {
		ip = r.RemoteAddr
	}

	visit := &Visit{
		IP:        ip,
		Host:      url.Host,
		Path:      url.Path,
		CreatedAt: time.Now().UTC().Format(time.RFC3339),
	}
	log.Println("Logging visit:", visit.String())

	err = visit.Save()

	if err != nil {
		http.Error(w, err.Error(), 500)
		return
	}
}

func main() {
	goji.Get("/ping", ping)
	goji.Get("/ping.js", ping)
	goji.Serve()
}

--- 
+++ 
@@ -11,7 +11,8 @@
 )
 
 func ping(w http.ResponseWriter, r *http.Request) {
-	fmt.Fprintf(w, "")
+	w.Header().Set("Content-Type", "application/javascript")
+	fmt.Fprintf(w, "(function(){})();")
 
 	referrer := r.Referer()
 	if referrer == "" {
Set Content-Type header to ensure we're sending javascript
