added logging

server.go

@@ -4,11 +4,13 @@ import (
 	"fmt"
 	"log"
 	"net/http"
+	"os"
 )
 
 func handler(w http.ResponseWriter, r *http.Request) {
 	ip := GetRealIP(r)
 	fmt.Fprintf(w, ip)
+	WritetoFile(ip)
 }
 
 func GetRealIP(r *http.Request) string {
@@ -24,6 +26,17 @@ func GetRealIP(r *http.Request) string {
 	}
 	return IP
 }
+func WritetoFile(IP string) {
+	f, err := os.OpenFile("ListofIPs.txt",
+		os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
+	if err != nil {
+		log.Println(err)
+	}
+	defer f.Close()
+	if _, err := f.WriteString(IP + "\n"); err != nil {
+		log.Println(err)
+	}
+}
 func main() {
 	http.HandleFunc("/", handler)
 	log.Fatal(http.ListenAndServe(":8081", nil))