Beispiel #1
0
// JWTAccessTokenSourceFromJSON uses a Google Developers service account JSON
// key file to read the credentials that authorize and authenticate the
// requests, and returns a TokenSource that does not use any OAuth2 flow but
// instead creates a JWT and sends that as the access token.
// The audience is typically a URL that specifies the scope of the credentials.
//
// Note that this is not a standard OAuth flow, but rather an
// optimization supported by a few Google services.
// Unless you know otherwise, you should use JWTConfigFromJSON instead.
func JWTAccessTokenSourceFromJSON(jsonKey []byte, audience string) (oauth2.TokenSource, error) {
	cfg, err := JWTConfigFromJSON(jsonKey)
	if err != nil {
		return nil, fmt.Errorf("google: could not parse JSON key: %v", err)
	}
	pk, err := internal.ParseKey(cfg.PrivateKey)
	if err != nil {
		return nil, fmt.Errorf("google: could not parse key: %v", err)
	}
	ts := &jwtAccessTokenSource{
		email:    cfg.Email,
		audience: audience,
		pk:       pk,
	}
	tok, err := ts.Token()
	if err != nil {
		return nil, err
	}
	return oauth2.ReuseTokenSource(tok, ts), nil
}
Beispiel #2
0
func (js jwtSource) Token() (*oauth2.Token, error) {
	pk, err := internal.ParseKey(js.conf.PrivateKey)
	if err != nil {
		return nil, err
	}
	hc := oauth2.NewClient(js.ctx, nil)
	claimSet := &jws.ClaimSet{
		Iss:   js.conf.Email,
		Scope: strings.Join(js.conf.Scopes, " "),
		Aud:   js.conf.TokenURL,
	}
	if subject := js.conf.Subject; subject != "" {
		claimSet.Sub = subject
		// prn is the old name of sub. Keep setting it
		// to be compatible with legacy OAuth 2.0 providers.
		claimSet.Prn = subject
	}
	if t := js.conf.Expires; t > 0 {
		claimSet.Exp = time.Now().Add(t).Unix()
	}
	payload, err := jws.Encode(defaultHeader, claimSet, pk)
	if err != nil {
		return nil, err
	}
	v := url.Values{}
	v.Set("grant_type", defaultGrantType)
	v.Set("assertion", payload)
	resp, err := hc.PostForm(js.conf.TokenURL, v)
	if err != nil {
		return nil, fmt.Errorf("oauth2: cannot fetch token: %v", err)
	}
	defer resp.Body.Close()
	body, err := ioutil.ReadAll(io.LimitReader(resp.Body, 1<<20))
	if err != nil {
		return nil, fmt.Errorf("oauth2: cannot fetch token: %v", err)
	}
	if c := resp.StatusCode; c < 200 || c > 299 {
		return nil, fmt.Errorf("oauth2: cannot fetch token: %v\nResponse: %s", resp.Status, body)
	}
	// tokenRes is the JSON response body.
	var tokenRes struct {
		AccessToken string `json:"access_token"`
		TokenType   string `json:"token_type"`
		IDToken     string `json:"id_token"`
		ExpiresIn   int64  `json:"expires_in"` // relative seconds from now
	}
	if err := json.Unmarshal(body, &tokenRes); err != nil {
		return nil, fmt.Errorf("oauth2: cannot fetch token: %v", err)
	}
	token := &oauth2.Token{
		AccessToken: tokenRes.AccessToken,
		TokenType:   tokenRes.TokenType,
	}
	raw := make(map[string]interface{})
	json.Unmarshal(body, &raw) // no error checks for optional fields
	token = token.WithExtra(raw)

	if secs := tokenRes.ExpiresIn; secs > 0 {
		token.Expiry = time.Now().Add(time.Duration(secs) * time.Second)
	}
	if v := tokenRes.IDToken; v != "" {
		// decode returned id token to get expiry
		claimSet, err := jws.Decode(v)
		if err != nil {
			return nil, fmt.Errorf("oauth2: error decoding JWT token: %v", err)
		}
		token.Expiry = time.Unix(claimSet.Exp, 0)
	}
	return token, nil
}