refactor:使用指定DNS彻底解决DNS缓存导致的问题

Util/checker.go

@@ -1,36 +1,23 @@
 package Util
 
 import (
-	"Mmx/Request"
-	"fmt"
+	"context"
 	"net"
-	"time"
 )
 
 type checker struct{}
 
 var Checker checker
 
-func (checker) NetOk(url string) bool {
-	if ip, err := net.LookupIP("www.msftconnecttest.com"); err != nil { //通过DNS确认是否在线
+func (checker) NetOk() bool {
+	r := &net.Resolver{ //指定DNS，防止本地DNS缓存影响
+		PreferGo: true,
+		Dial:     NetDailEr(),
+	}
+	if ip, err := r.LookupIP(context.Background(), "ip4", "www.msftconnecttest.com"); err != nil { //通过DNS确认是否在线
 		return false
 	} else if len(ip) == 0 || ip[0].String() != "13.107.4.52" {
 		return false
 	}
-
-	{ //有些路由器有DNS缓存，故进行进一步确认
-		body, err := Request.Get(url, map[string]string{
-			"callback": "jQuery1635413",
-			"_":        fmt.Sprint(time.Now().UnixNano()),
-		})
-		ErrHandler(err)
-		r, err := GetResult(body)
-		if err != nil {
-			ErrHandler(err)
-		}
-		if r != "ok" {
-			return false
-		}
-	}
 	return true
 }

Util/util.go

@@ -2,13 +2,16 @@ package Util
 
 import (
 	"Mmx/Global"
+	"context"
 	"crypto/md5"
 	"crypto/sha1"
 	"errors"
 	"fmt"
 	"io"
+	"net"
 	"os"
 	"regexp"
+	"time"
 )
 
 func Search(reg string, content string) (string, error) {
@@ -57,3 +60,12 @@ func ErrHandler(err error) {
 		os.Exit(1)
 	}
 }
+
+func NetDailEr() func(ctx context.Context, network, address string) (net.Conn, error) {
+	return func(ctx context.Context, network, address string) (net.Conn, error) {
+		d := net.Dialer{
+			Timeout: 20 * time.Second,
+		}
+		return d.DialContext(ctx, "udp", "1.2.4.8:53")
+	}
+}