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dex/refresh/repo.go

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2015-08-18 05:57:27 +05:30
package refresh
import (
"crypto/rand"
"encoding/base64"
"errors"
"fmt"
"strconv"
"strings"
)
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() (string, error)
func (g RefreshTokenGenerator) Generate() (string, error) {
return g()
}
func DefaultRefreshTokenGenerator() (string, error) {
// TODO(yifan) Remove this duplicated token generate function.
b := make([]byte, DefaultRefreshTokenPayloadLength)
n, err := rand.Read(b)
if err != nil {
return "", err
} else if n != DefaultRefreshTokenPayloadLength {
return "", errors.New("unable to read enough random bytes")
}
return base64.URLEncoding.EncodeToString(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
}
type refreshToken struct {
payload string
userID string
clientID string
}
type memRefreshTokenRepo struct {
store map[int]refreshToken
tokenGenerator RefreshTokenGenerator
}
// buildToken combines the token ID and token payload to create a new token.
func buildToken(tokenID int, tokenPayload string) string {
return fmt.Sprintf("%d%s%s", tokenID, TokenDelimer, tokenPayload)
}
// parseToken parses a token and returns the token ID and token payload.
func parseToken(token string) (int, string, error) {
parts := strings.SplitN(token, TokenDelimer, 2)
if len(parts) != 2 {
return -1, "", ErrorInvalidToken
}
id, err := strconv.Atoi(parts[0])
if err != nil {
return -1, "", ErrorInvalidToken
}
return id, parts[1], nil
}
// NewRefreshTokenRepo returns an in-memory RefreshTokenRepo useful for development.
func NewRefreshTokenRepo() RefreshTokenRepo {
return NewRefreshTokenRepoWithTokenGenerator(DefaultRefreshTokenGenerator)
}
func NewRefreshTokenRepoWithTokenGenerator(tokenGenerator RefreshTokenGenerator) RefreshTokenRepo {
repo := &memRefreshTokenRepo{}
repo.store = make(map[int]refreshToken)
repo.tokenGenerator = tokenGenerator
return repo
}
func (r *memRefreshTokenRepo) Create(userID, clientID string) (string, error) {
// Validate userID.
if userID == "" {
return "", ErrorInvalidUserID
}
// Validate clientID.
if clientID == "" {
return "", ErrorInvalidClientID
}
// Generate and store token.
tokenPayload, err := r.tokenGenerator.Generate()
if err != nil {
return "", err
}
tokenID := len(r.store) // Should only be used in single threaded tests.
// No limits on the number of tokens per user/client for this in-memory repo.
r.store[tokenID] = refreshToken{
payload: tokenPayload,
userID: userID,
clientID: clientID,
}
return buildToken(tokenID, tokenPayload), nil
}
func (r *memRefreshTokenRepo) Verify(clientID, token string) (string, error) {
tokenID, tokenPayload, err := parseToken(token)
if err != nil {
return "", err
}
record, ok := r.store[tokenID]
if !ok {
return "", ErrorInvalidToken
}
if record.payload != tokenPayload {
return "", ErrorInvalidToken
}
if record.clientID != clientID {
return "", ErrorInvalidClientID
}
return record.userID, nil
}
func (r *memRefreshTokenRepo) Revoke(userID, token string) error {
tokenID, tokenPayload, err := parseToken(token)
if err != nil {
return err
}
record, ok := r.store[tokenID]
if !ok {
return ErrorInvalidToken
}
if record.payload != tokenPayload {
return ErrorInvalidToken
}
if record.userID != userID {
return ErrorInvalidUserID
}
delete(r.store, tokenID)
return nil
}