==> GET /hello HTTP/1.1 Host: 127.0.0.1:12345 <== HTTP/1.1 401 Unauthorized WWW-Authenticate: Basic realm="Dotcoo User Login" ==> GET /hello HTTP/1.1 Host: 127.0.0.1:12345 Authorization: Basic YWRtaW46YWRtaW5wd2Q= <== HTTP/1.1 200 OK Content-Type: text/plain; charset=utf-8

package main import (     "fmt"     "io"     "net/http"     "log"     "encoding/base64"     "strings" ) // hello world, the web server func HelloServer(w http.ResponseWriter, req *http.Request) {     auth := req.Header.Get("Authorization")     if auth == "" {         w.Header().Set("WWW-Authenticate", `Basic realm="Dotcoo User Login"`)         w.WriteHeader(http.StatusUnauthorized)         return     }     fmt.Println(auth)     auths := strings.SplitN(auth, " ", 2)     if len(auths) != 2 {         fmt.Println("error")         return     }     authMethod := auths[0]     authB64 := auths[1]     switch authMethod {     case "Basic":         authstr, err := base64.StdEncoding.DecodeString(authB64)         if err != nil {             fmt.Println(err)             io.WriteString(w, "Unauthorized!\n")             return         }         fmt.Println(string(authstr))         userPwd := strings.SplitN(string(authstr), ":", 2)         if len(userPwd) != 2 {             fmt.Println("error")             return         }         username := userPwd[0]         password := userPwd[1]         fmt.Println("Username:", username)         fmt.Println("Password:", password)         fmt.Println()     default:         fmt.Println("error")         return     }     io.WriteString(w, "hello, world!\n") } func main() {     http.HandleFunc("/hello", HelloServer)     err := http.ListenAndServe(":12345", nil)     if err != nil {         log.Fatal("ListenAndServe: ", err)     } }