lancet/netutil/net.go

package netutil

import (
	"encoding/json"
	"io/ioutil"
	"net"
	"net/http"
	"net/url"
	"strings"
)

// GetInternalIp return internal ipv4
func GetInternalIp() string {
	addr, err := net.InterfaceAddrs()
	if err != nil {
		panic(err.Error())
	}
	for _, a := range addr {
		if ipNet, ok := a.(*net.IPNet); ok && !ipNet.IP.IsLoopback() {
			if ipNet.IP.To4() != nil {
				return ipNet.IP.String()
			}
		}
	}

	return ""
}

// GetPublicIpInfo return public ip information
// return the PublicIpInfo struct
func GetPublicIpInfo() (*PublicIpInfo, error) {
	resp, err := http.Get("http://ip-api.com/json/")
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	body, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}

	var ip PublicIpInfo
	err = json.Unmarshal(body, &ip)
	if err != nil {
		return nil, err
	}

	return &ip, nil
}

// GetRequestPublicIp return the requested public ip
func GetRequestPublicIp(req *http.Request) string {
	var ip string
	for _, ip = range strings.Split(req.Header.Get("X-Forwarded-For"), ",") {
		if ip = strings.TrimSpace(ip); ip != "" && !IsInternalIP(net.ParseIP(ip)) {
			return ip
		}
	}

	if ip = strings.TrimSpace(req.Header.Get("X-Real-Ip")); ip != "" && !IsInternalIP(net.ParseIP(ip)) {
		return ip
	}

	if ip, _, _ = net.SplitHostPort(req.RemoteAddr); !IsInternalIP(net.ParseIP(ip)) {
		return ip
	}

	return ip
}

// GetIps return all ipv4 of system
func GetIps() []string {
	var ips []string

	addrs, err := net.InterfaceAddrs()
	if err != nil {
		return ips
	}

	for _, addr := range addrs {
		ipNet, isValid := addr.(*net.IPNet)
		if isValid && !ipNet.IP.IsLoopback() {
			if ipNet.IP.To4() != nil {
				ips = append(ips, ipNet.IP.String())
			}
		}
	}
	return ips
}

// GetMacAddrs get mac address
func GetMacAddrs() []string {
	var macAddrs []string

	nets, err := net.Interfaces()
	if err != nil {
		return macAddrs
	}

	for _, net := range nets {
		macAddr := net.HardwareAddr.String()
		if len(macAddr) == 0 {
			continue
		}
		macAddrs = append(macAddrs, macAddr)
	}

	return macAddrs
}

// PublicIpInfo public ip info: country, region, isp, city, lat, lon, ip
type PublicIpInfo struct {
	Status      string  `json:"status"`
	Country     string  `json:"country"`
	CountryCode string  `json:"countryCode"`
	Region      string  `json:"region"`
	RegionName  string  `json:"regionName"`
	City        string  `json:"city"`
	Lat         float64 `json:"lat"`
	Lon         float64 `json:"lon"`
	Isp         string  `json:"isp"`
	Org         string  `json:"org"`
	As          string  `json:"as"`
	Ip          string  `json:"query"`
}

// IsPublicIP verify a ip is public or not
func IsPublicIP(IP net.IP) bool {
	if IP.IsLoopback() || IP.IsLinkLocalMulticast() || IP.IsLinkLocalUnicast() {
		return false
	}
	if ip4 := IP.To4(); ip4 != nil {
		switch {
		case ip4[0] == 10:
			return false
		case ip4[0] == 172 && ip4[1] >= 16 && ip4[1] <= 31:
			return false
		case ip4[0] == 192 && ip4[1] == 168:
			return false
		default:
			return true
		}
	}
	return false
}

// IsInternalIP verify an ip is intranet or not
func IsInternalIP(IP net.IP) bool {
	if IP.IsLoopback() {
		return true
	}
	if ip4 := IP.To4(); ip4 != nil {
		return ip4[0] == 10 ||
			(ip4[0] == 172 && ip4[1] >= 16 && ip4[1] <= 31) ||
			(ip4[0] == 169 && ip4[1] == 254) ||
			(ip4[0] == 192 && ip4[1] == 168)
	}
	return false
}

// EncodeUrl encode url
func EncodeUrl(urlStr string) (string, error) {
	URL, err := url.Parse(urlStr)
	if err != nil {
		return "", err
	}

	URL.RawQuery = URL.Query().Encode()

	return URL.String(), nil
}