Function GetIP

api/get_ip.go:22–63

GetIP returns a user's public facing IP address (IPv4 OR IPv6). By default, it will return the IP address in plain text, but can also return data in both JSON and JSONP if requested to.

(w http.ResponseWriter, r *http.Request, _ httprouter.Params)

// By default, it will return the IP address in plain text, but can also return
// data in both JSON and JSONP if requested to.
func GetIP(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {

	err := r.ParseForm()
	if err != nil {
		panic(err)
	}

	// We'll always grab the first IP address in the X-Forwarded-For header
	// list.  We do this because this is always the *origin* IP address, which
	// is the *true* IP of the user.  For more information on this, see the
	// Wikipedia page: https://en.wikipedia.org/wiki/X-Forwarded-For
	ip := net.ParseIP(strings.Split(r.Header.Get("X-Forwarded-For"), ",")[0]).String()

	// If the user specifies a 'format' querystring, we'll try to return the
	// user's IP address in the specified format.
	if format, ok := r.Form["format"]; ok && len(format) > 0 {
		jsonStr, _ := json.Marshal(models.IPAddress{ip})

		switch format[0] {
		case "json":
			w.Header().Set("Content-Type", "application/json")
			fmt.Fprintf(w, string(jsonStr))
			return
		case "jsonp":
			// If the user specifies a 'callback' parameter, we'll use that as
			// the name of our JSONP callback.
			callback := "callback"
			if val, ok := r.Form["callback"]; ok && len(val) > 0 {
				callback = val[0]
			}

			w.Header().Set("Content-Type", "application/javascript")
			fmt.Fprintf(w, callback+"("+string(jsonStr)+");")
			return
		}
	}

	// If no 'format' querystring was specified, we'll default to returning the
	// IP in plain text.
	w.Header().Set("Content-Type", "text/plain")
	fmt.Fprintf(w, ip)
}