使用googleapis lib獲取refresh_token

因此，我使用Google Oauth流設置使用googleapis庫，並且在使用oauthClient.getToken(code, ..)之後，我似乎沒有看到refresh_token。它只返回access_token和id_token。使用googleapis lib獲取refresh_token

下面是從代碼我的結果：

{ 
    access_token: "...", 
    expiry_date: 1475080667529, 
    id_token: "...", 
    token_type: "Bearer" 
}

這裏是我的代碼：

function getOauth() { 
    var oauthClient = new google.auth.OAuth2(
    config.googleOauth.id, 
    config.googleOauth.secret, 
    `${config.https ? 'https' : 'http'}://${config.baseUrl}/google` 
); 
    return Bluebird.promisifyAll(oauthClient); 
} 

/** 
* Initialize session based of the auth code, which 
* gives us the accessToken and the payload. 
* 
* Returns a session with the user tokenized and 
* the accessToken for use to restore on page refresh. 
*/ 
router.get('/initial', function * (req, res) { 
    try { 
    let oauth = getOauth(); 
    let code = req.query.authorizationCode; 
    let results = yield oauth.getTokenAsync(code); 
    let tokens = results[0]; 
    let result = yield oauth.verifyIdTokenAsync(tokens.id_token, config.googleOauth.id); 
    let payload = result.getPayload(); 
    let user = yield User.findOneByEmail(payload.email, req.communityConfig); 
    let data = { user }; 

    if (user.role) { 
     let role = yield Role.findOne(user.role, req.communityConfig); 
     data.roles = [role]; 
    } 

    let token = auth.createToken(data); 

    res.json(extend({}, req.query, { token, accessToken: tokens.id_token })); 
    } catch(error) { 
    console.log(error.message); 
    throw new StatusError(401, error); 
    } 
}); 

/** 
* Use the google provider's fetch method to restore the session 
* data using the accessToken. 
* 
* Returns a token created from the user and role, along with 
* all of the query props passed in. 
*/ 
router.get('/restore', function * (req, res) { 
    try { 
    let oauth = getOauth(); 

    oauth.setCredentials({ 
     access_token: req.query.accessToken 
    }); 

    let tokens = yield oauth.getAccessTokenAsync(); 
    let result = yield oauth.verifyIdTokenAsync(tokens[0], config.googleOauth.id); 
    let payload = result.getPayload(); 
    let user = yield User.findOneByEmail(payload.email, req.communityConfig); 
    let data = { user }; 

    if (user.role) { 
     let role = yield Role.findOne(user.role, req.communityConfig); 
     data.roles = [role]; 
    } 

    let token = auth.createToken(data); 

    res.json(extend({}, req.query, { token })); 
    } catch(error) { 
    console.log(error.message); 
    throw new StatusError(401, error); 
    } 
});

所以一切正常，在初始和刷新，但access_token到期後，不再進行身份驗證。