package refresh
import (
"crypto/rand"
"errors"
)
const (
DefaultRefreshTokenPayloadLength = 64
TokenDelimer = "/"
var (
ErrorInvalidUserID = errors.New("invalid user ID")
ErrorInvalidClientID = errors.New("invalid client ID")
ErrorInvalidToken = errors.New("invalid token")
type RefreshTokenGenerator func() ([]byte, error)
func (g RefreshTokenGenerator) Generate() ([]byte, error) {
return g()
}
func DefaultRefreshTokenGenerator() ([]byte, error) {
// TODO(yifan) Remove this duplicated token generate function.
b := make([]byte, DefaultRefreshTokenPayloadLength)
n, err := rand.Read(b)
if err != nil {
return nil, err
if n != DefaultRefreshTokenPayloadLength {
return nil, errors.New("unable to read enough random bytes")
return b, nil
type RefreshTokenRepo interface {
// Create generates and returns a new refresh token for the given client-user pair.
// On success the token will be return.
Create(userID, clientID string) (string, error)
// Verify verifies that a token belongs to the client, and returns the corresponding user ID.
// Note that this assumes the client validation is currently done in the application layer,
Verify(clientID, token string) (string, error)
// Revoke deletes the refresh token if the token belongs to the given userID.
Revoke(userID, token string) error