feat: add func GetRequestPublicIp and IsInternalIP (#40)

* add: add func GetRequestPublicIp and IsInternalIP

* fix: fix test fileutil fail

Co-authored-by: zhanghu <305835360@qq.com>

netutil/net.go

@@ -5,6 +5,7 @@ import (
 	"io/ioutil"
 	"net"
 	"net/http"
+	"strings"
 )
 
 // GetInternalIp return internal ipv4
@@ -24,6 +25,26 @@ func GetInternalIp() string {
 	return ""
 }
 
+// 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
+}
+
 // GetPublicIpInfo return public ip information
 // return the PublicIpInfo struct
 func GetPublicIpInfo() (*PublicIpInfo, error) {
@@ -122,3 +143,17 @@ func IsPublicIP(IP net.IP) bool {
 	}
 	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
+}

netutil/net_test.go

@@ -2,6 +2,7 @@ package netutil
 
 import (
 	"net"
+	"net/http"
 	"testing"
 
 	"github.com/duke-git/lancet/v2/internal"
@@ -15,6 +16,30 @@ func TestGetInternalIp(t *testing.T) {
 	assert.IsNotNil(ip)
 }
 
+func TestGetRequestPublicIp(t *testing.T) {
+	assert := internal.NewAssert(t, "TestGetPublicIpInfo")
+
+	ip := "36.112.24.10"
+
+	request := http.Request{
+		Method: "GET",
+		Header: http.Header{
+			"X-Forwarded-For": {ip},
+		},
+	}
+	publicIp := GetRequestPublicIp(&request)
+	assert.Equal(publicIp, ip)
+
+	request = http.Request{
+		Method: "GET",
+		Header: http.Header{
+			"X-Real-Ip": {ip},
+		},
+	}
+	publicIp = GetRequestPublicIp(&request)
+	assert.Equal(publicIp, ip)
+}
+
 func TestGetPublicIpInfo(t *testing.T) {
 	assert := internal.NewAssert(t, "TestGetPublicIpInfo")
 
@@ -43,6 +68,25 @@ func TestIsPublicIP(t *testing.T) {
 	}
 }
 
+func TestIsInternalIP(t *testing.T) {
+	assert := internal.NewAssert(t, "TestIsInternalIP")
+
+	ips := []net.IP{
+		net.ParseIP("127.0.0.1"),
+		net.ParseIP("192.168.0.1"),
+		net.ParseIP("10.91.210.131"),
+		net.ParseIP("172.20.16.1"),
+		net.ParseIP("36.112.24.10"),
+	}
+
+	expected := []bool{true, true, true, true, false}
+
+	for i := 0; i < len(ips); i++ {
+		actual := IsInternalIP(ips[i])
+		assert.Equal(expected[i], actual)
+	}
+}
+
 func TestGetIps(t *testing.T) {
 	ips := GetIps()
 	t.Log(ips)