示例#1
0
文件: oauth.go 项目: 0x7cc/rsc
// Token obtains an OAuth token, keeping a cached copy in file.
// If the file name is not an absolute path, it is interpreted relative to the
// user's home directory.
func Token(file string, cfg *oauth.Config) (*oauth.Transport, error) {
	if !filepath.IsAbs(file) {
		file = filepath.Join(os.Getenv("HOME"), file)
	}
	cfg1 := *cfg
	cfg = &cfg1
	cfg.TokenCache = oauth.CacheFile(file)
	tok, err := cfg.TokenCache.Token()
	if err == nil {
		return &oauth.Transport{Config: cfg, Token: tok}, nil
	}

	// Start HTTP server on localhost.
	l, err := net.Listen("tcp", "127.0.0.1:0")
	if err != nil {
		var err1 error
		if l, err1 = net.Listen("tcp6", "[::1]:0"); err1 != nil {
			return nil, fmt.Errorf("oauthprompt.Token: starting HTTP server: %v", err)
		}
	}

	type done struct {
		err  error
		code string
	}
	ch := make(chan done, 100)

	randState, err := randomID()
	if err != nil {
		return nil, err
	}

	cfg.RedirectURL = "http://" + l.Addr().String() + "/done"
	authURL := cfg1.AuthCodeURL(randState)

	handler := http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		if req.URL.Path == "/auth" {
			http.Redirect(w, req, authURL, 301)
			return
		}
		if req.URL.Path != "/done" {
			http.Error(w, "", 404)
			return
		}
		if req.FormValue("state") != randState {
			ch <- done{err: fmt.Errorf("oauthprompt.Token: incorrect response")}
			http.Error(w, "", 500)
			return
		}
		if code := req.FormValue("code"); code != "" {
			ch <- done{code: code}
			w.Write([]byte(success))
			return
		}
		http.Error(w, "", 500)
	})

	srv := &http.Server{Handler: handler}
	go srv.Serve(l)
	if err := openURL("http://" + l.Addr().String() + "/auth"); err != nil {
		l.Close()
		return nil, err
	}
	d := <-ch
	l.Close()

	if d.err != nil {
		return nil, err
	}

	tr := &oauth.Transport{Config: &cfg1}
	_, err = tr.Exchange(d.code)
	if err != nil {
		return nil, err
	}
	return tr, nil
}