使用Golong实现JWT身份验证的详细过程

package main
import (
 "fmt"
 "github.com/golang-jwt/jwt/v4"
 "time"
)
var mySigningKey = []byte("secretpassword")
func GenerateJWT() (string, error) {
 token := jwt.New(jwt.SigningMethodHS256)
 claims := token.Claims.(jwt.MapClaims)
 claims["authorized"] = true
 claims["user"] = "John Doe"
 claims["exp"] = time.Now().Add(time.Minute * 30).Unix()
 tokenString, err := token.SignedString(mySigningKey)
 if err != nil {
  fmt.Errorf("Something went wrong: %s", err.Error())
  return "", err
 }
 return tokenString, nil
}

func ValidateToken(tokenString string) (*jwt.Token, error) {
 token, err := jwt.Parse(tokenString, func(token *jwt.Token) (interface{}, error) {
  if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
   return nil, fmt.Errorf("There was an error")
  }
  return mySigningKey, nil
 })
 if err != nil {
   return nil, err
 }
 return token, nil
}

package main
import (
 "fmt"
 "log"
 "net/http"
)
func HomePage(w http.ResponseWriter, r *http.Request) {
 validToken, err := GenerateJWT()
 if err != nil {
  fmt.Fprintf(w, err.Error())
 }
 clientToken := r.Header.Get("Token")
 if clientToken != validToken {
  w.WriteHeader(http.StatusUnauthorized)
  fmt.Fprintf(w, "Token is not valid")
  return
 }
 fmt.Fprintf(w, "Hello, World!")
}
func handleRequests() {
 http.HandleFunc("/", HomePage)
 log.Fatal(http.ListenAndServe(":9000", nil))
}
func main() {
 handleRequests()
}