jwt example

jwt_example.go

package main

import (
	"errors"
	"fmt"
	"github.com/dgrijalva/jwt-go"
	"time"
)

type User struct {
	username string
}

func generateLoginToken(mySigningKey []byte, user User) (string, error) {
	// Create the token
	token := jwt.New(jwt.SigningMethodHS256)
	token.Header["kind"] = "login"
	// Set some claims
	token.Claims["username"] = user.username
	token.Claims["exp"] = time.Now().Add(time.Hour * 72).Unix()
	// Sign and get the complete encoded token as a string
	tokenString, err := token.SignedString(mySigningKey)
	return tokenString, err
}

func parseLoginToken(myToken string, myLookupKey func(interface{}) (interface{}, error)) (User, error) {
	token, err := jwt.Parse(myToken, func(token *jwt.Token) (interface{}, error) {
		fmt.Println(myToken)
		return myLookupKey(token.Header["kind"])
	})

	fmt.Println("token", token)

	if token.Valid {
		fmt.Println("You look nice today")
		return User{token.Claims["username"].(string)}, nil
	} else if ve, ok := err.(*jwt.ValidationError); ok {
		if ve.Errors&jwt.ValidationErrorMalformed != 0 {
			fmt.Println("That's not even a token")
			return User{}, err
		} else if ve.Errors&(jwt.ValidationErrorExpired|jwt.ValidationErrorNotValidYet) != 0 {
			// Token is either expired or not active yet
			fmt.Println("Timing is everything")
			return User{}, err
		} else {
			fmt.Println("Couldn't handle this token:", err)
			return User{}, err
		}
	} else {
		fmt.Println("Couldn't handle this token:", err)
		return User{}, err
	}

}

func look(kind interface{}) (interface{}, error) {
	if str, ok := kind.(string); ok {
		switch str {
		case "login":
			return []byte("mySigningKey"), nil
		}
	}

	return "", errors.New("unknown jwt kind")
}

func main() {
	user := User{"username"}
	jwt, _ := generateLoginToken([]byte("mySigningKey"), user)
	value, _ := parseLoginToken(jwt, look)
	fmt.Println("value", value)
}