Golang获取HTTP请求IP

// GetIP returns request real ip.
func GetIP(r *http.Request) (string, error) {
	ip := r.Header.Get("X-Real-IP")
	if net.ParseIP(ip) != nil {
		return ip, nil
	}

	ip = r.Header.Get("X-Forward-For")
	for _, i := range strings.Split(ip, ",") {
		if net.ParseIP(i) != nil {
			return i, nil
		}
	}

	ip, _, err := net.SplitHostPort(r.RemoteAddr)
	if err != nil {
		return "", err
	}

	if net.ParseIP(ip) != nil {
		return ip, nil
	}
	
	return "", errors.New("no valid ip found")
}