util.go

package main

import (
	"errors"
	"net"
	"net/http"
	"strings"
)

func GetLocalIP() string {
	addrs, err := net.InterfaceAddrs()
	if err != nil {
		return ""
	}
	for _, address := range addrs {
		// check the address type and if it is not a loopback the display it
		if ipnet, ok := address.(*net.IPNet); ok && !ipnet.IP.IsLoopback() {
			if ipnet.IP.To4() != nil {
				return ipnet.IP.String()
			}
		}
	}
	return ""
}

func GetClientIP(r *http.Request) (string, error) {
	ips := r.Header.Get("X-Forwarded-For")
	splitIps := strings.Split(ips, ",")
	if len(splitIps) > 0 {
		netIP := net.ParseIP(splitIps[len(splitIps)-1])
		if netIP != nil {
			return netIP.String(), nil
		}
	}
	ip, _, err := net.SplitHostPort(r.RemoteAddr)
	if err != nil {
		return "", err
	}
	netIP := net.ParseIP(ip)
	if netIP != nil {
		ip := netIP.String()
		if ip == "::1" {
			return "127.0.0.1", nil
		}
		return ip, nil
	}
	return "", errors.New("parse client ip failed")
}