forked from Mirrors/oauth2
69 lines
1.6 KiB
Go
69 lines
1.6 KiB
Go
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// Copyright 2014 The oauth2 Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package google
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import (
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"errors"
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"sort"
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"strings"
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"sync"
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"time"
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"golang.org/x/oauth2"
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)
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var (
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aeTokensMu sync.Mutex // guards aeTokens and appEngineTokenSource.key
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// aeTokens helps the fetched tokens to be reused until their expiration.
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aeTokens = make(map[string]*tokenLock) // key is '\0'-separated scopes
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)
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var errInvalidContext = errors.New("oauth2: a valid appengine.Context is required")
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type tokenLock struct {
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mu sync.Mutex // guards t; held while updating t
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t *oauth2.Token
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}
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type appEngineTokenSource struct {
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ctx oauth2.Context
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scopes []string
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key string // guarded by package-level mutex, aeTokensMu
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// fetcherFunc makes the actual RPC to fetch a new access token with an expiry time.
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// Provider of this function is responsible to assert that the given context is valid.
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fetcherFunc func(ctx oauth2.Context, scope ...string) (string, time.Time, error)
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}
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func (ts *appEngineTokenSource) Token() (*oauth2.Token, error) {
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aeTokensMu.Lock()
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if ts.key == "" {
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sort.Sort(sort.StringSlice(ts.scopes))
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ts.key = strings.Join(ts.scopes, string(0))
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}
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tok, ok := aeTokens[ts.key]
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if !ok {
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tok = &tokenLock{}
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aeTokens[ts.key] = tok
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}
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aeTokensMu.Unlock()
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tok.mu.Lock()
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defer tok.mu.Unlock()
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if tok.t != nil && !tok.t.Expired() {
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return tok.t, nil
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}
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access, exp, err := ts.fetcherFunc(ts.ctx, ts.scopes...)
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if err != nil {
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return nil, err
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}
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tok.t = &oauth2.Token{
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AccessToken: access,
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Expiry: exp,
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}
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return tok.t, nil
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}
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