evcc-io/vehicle/vag/tokensource.go
2023-10-06 17:08:20 +02:00

128 lines
2.8 KiB
Go

package vag
import (
"net/url"
"sync"
"time"
"dario.cat/mergo"
"golang.org/x/oauth2"
)
// TokenSource is a VAG token source compatible with oauth2.TokenSource
type TokenSource interface {
// Token returns an OAuth2 compatible token (id_token omitted)
Token() (*oauth2.Token, error)
// TokenEx returns the extended VAG token (id_token included)
TokenEx() (*Token, error)
}
// TokenExchanger exchanges a VW identity response into a (refreshing) VAG token source
type TokenExchanger interface {
Exchange(q url.Values) (*Token, error)
TokenSource(token *Token) TokenSource
}
// TokenRefresher refreshes a token
type TokenRefresher func(*Token) (*Token, error)
var _ TokenSource = (*tokenSource)(nil)
type tokenSource struct {
mu sync.Mutex
token *Token
new TokenRefresher
}
func RefreshTokenSource(token *Token, refresher TokenRefresher) *tokenSource {
return &tokenSource{token: token, new: refresher}
}
// Token returns an oauth2 token or an error
func (ts *tokenSource) Token() (*oauth2.Token, error) {
token, err := ts.TokenEx()
if err != nil {
return nil, err
}
return &token.Token, err
}
func (ts *tokenSource) TokenEx() (*Token, error) {
ts.mu.Lock()
defer ts.mu.Unlock()
var err error
if time.Until(ts.token.Expiry) < time.Minute {
var token *Token
if token, err = ts.new(ts.token); err == nil {
err = ts.mergeToken(token)
}
}
return ts.token, err
}
// mergeToken updates a token while preventing wiping the refresh token
func (ts *tokenSource) mergeToken(t *Token) error {
return mergo.Merge(ts.token, t, mergo.WithOverride)
}
type metaTokenSource struct {
mu sync.Mutex
ts TokenSource
newT func() (*Token, error)
newTS func(*Token) TokenSource
}
// MetaTokenSource creates a token source that is created using the
// `newTS` function or recreated once it fails to return tokens.
// The recreation uses a new bootstrap token provided by the `newT` function.
func MetaTokenSource(newT func() (*Token, error), newTS func(*Token) TokenSource) *metaTokenSource {
return &metaTokenSource{
newT: newT,
newTS: newTS,
}
}
// Token returns an oauth2 token or an error
func (ts *metaTokenSource) Token() (*oauth2.Token, error) {
token, err := ts.TokenEx()
if err != nil {
return nil, err
}
return &token.Token, err
}
// Token returns a vag token or an error
func (ts *metaTokenSource) TokenEx() (*Token, error) {
ts.mu.Lock()
defer ts.mu.Unlock()
// use token source
if ts.ts != nil {
token, err := ts.ts.TokenEx()
if err == nil {
return token, nil
}
}
// create new start token
token, err := ts.newT()
if err != nil {
return nil, err
}
// create token source
ts.ts = ts.newTS(token)
// use token source
token, err = ts.ts.TokenEx()
if err != nil {
// token source doesn't work anymore, reset it
ts.ts = nil
}
return token, err
}