auth

var GenerateJWT = func(userID, secret string, expiresIn int) (string, error) {
	claims := jwt.MapClaims{}
	claims["authorized"] = true
	claims["sub"] = userID
	claims["iat"] = time.Now().Unix()
	if expiresIn != 0 {
		claims["exp"] = time.Now().Add(time.Minute * time.Duration(expiresIn)).Unix()
	}

	at := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
	return at.SignedString([]byte(secret))
}

var VerifyJWT = func(token, secret string) (string, error) {

	jwtToken, err := jwt.Parse(token, func(token *jwt.Token) (interface{}, error) {

		if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
			return nil, fmt.Errorf("unexpected signing method: %v", token.Header["alg"])
		}
		return []byte(secret), nil
	})
	if err != nil {
		return "", err
	}

	claims, ok := jwtToken.Claims.(jwt.MapClaims)
	if ok && jwtToken.Valid {
		userID, ok := claims["sub"].(string)
		if !ok {
			return "", errors.New("Failed to verify JWT and extract the subject")
		}

		return userID, nil
	}

	return "", errors.New("Failed to verify JWT and extract the subject")
}