main.go

package main

import (
	"fmt"
	"os"
	"time"

	"github.com/golang-jwt/jwt/v5"
)

var secretKey = []byte("myaktion-go-secret-key")

func createToken(username string) (string, error) {
	claims := jwt.NewWithClaims(jwt.SigningMethodHS256, jwt.MapClaims{
		"sub": username,
		"iss": "myaktion-go",
		"aud": "organizer",
		"exp": time.Now().Add(time.Hour).Unix(),
		"iat": time.Now().Unix(),
	})
	fmt.Printf("Token claims added: %+v\n", claims)
	tokenString, err := claims.SignedString(secretKey)
	if err != nil {
		return "", err
	}
	return tokenString, nil
}

func readUserFromToken(tokenString string) (string, error) {
	token, err := jwt.Parse(tokenString, func(token *jwt.Token) (interface{}, error) {
		return secretKey, nil
	})
	if err != nil {
		return "", err
	} else {
		if username, err := token.Claims.GetSubject(); err != nil {
			return "", err
		} else {
			return username, nil
		}
	}
}

func isValid(tokenString string) (bool, error) {
	_, err := jwt.Parse(tokenString, func(token *jwt.Token) (interface{}, error) {
		return secretKey, nil
	})
	if err != nil {
		return false, err
	}
	return true, nil
}

func main() {
	if len(os.Args) >= 2 {
		username := os.Args[1]
		tokenString, err := createToken(username)
		if err != nil {
			fmt.Printf("Unable to create token: %+v\n", err)
		} else {
			fmt.Printf("%+v\n", tokenString)
			//user, _ := readUserFromToken(tokenString)
			//fmt.Printf("found user in token: %+v\n", user)
		}
	} else {
		fmt.Println("Please pass a username as command-line argument")
	}
}