package mainimport (    "encoding/base64"    "encoding/json"    "log"    "net/http"    "strconv"    "strings"    "github.com/go-redis/redis"    "github.com/satori/go.uuid")type objMessage struct {    UID      int64  `json:"uid"`    UserName string `json:"user_name"`}type token struct {    Token string `json:"token"`}type tokenResponse struct {    Data token `json:"data"`}var client *redis.Clientfunc genToken(appid int, username string) string {    u2, _ := uuid.NewV4()    return u2.String()}func grantHandler(w http.ResponseWriter, r *http.Request) {    encodeBasic := strings.TrimPrefix(r.Header["Authorization"][0], "Basic ")    decodeBasic, _ := base64.StdEncoding.DecodeString(encodeBasic)    auth := string(decodeBasic)    appidStr := strings.Split(auth, ":")[0]    appid, _ := strconv.Atoi(appidStr)    var om objMessage    err := json.NewDecoder(r.Body).Decode(&om)    if err != nil {        http.Error(w, err.Error(), 400)        return    }    var tr tokenResponse    tr.Data.Token = genToken(appid, om.UserName)    fmap := make(map[string]interface{})    fmap["user_id"] = int64(om.UID)    fmap["app_id"] = int64(appid)    fmap["notification_on"] = int8(1)    fmap["forbidden"] = int(1)    client.HMSet("access_token_"+tr.Data.Token, fmap)    w.Header().Set("Content-Type", "application/json")    w.WriteHeader(http.StatusOK)    json.NewEncoder(w).Encode(tr)}func main() {    http.HandleFunc("/auth/grant", grantHandler)    client = redis.NewClient(&redis.Options{        Addr:     "172.16.0.201:6379",        Password: "", // no password set        DB:       1,  // use default DB    })    log.Fatal(http.ListenAndServe(":8090", nil))}