使用 OAuth 連結 Google 帳戶

帳戶連結使用業界標準 OAuth 2.0 隱含與授權碼流程。您的服務必須支援符合 OAuth 2.0 規定的授權和憑證交換端點。

在「暗示」流程中，Google 會在使用者的瀏覽器中開啟您的授權端點。成功登入後，會將長期存取憑證傳回 Google。目前從 Google 發出的每個要求都會包含這個存取憑證。

在「授權碼」流程中，您需要兩個端點：

• Authorization 端點，可為尚未登入的使用者顯示登入 UI。授權端點也會建立短期的授權碼來記錄使用者。同意要求的存取權。

• 憑證交換端點，該端點負責兩種交換類型：

  1. 將授權碼提供給長期使用憑證和短期存取憑證。當使用者完成帳戶連結流程時，系統就會執行這個交換作業。
  2. 針對短期存取權杖交換長期更新權杖。 如果 Google 需要這個存取憑證過期，因此需要進行這個交換作業。

選擇 OAuth 2.0 流程

雖然隱含流程比較簡單，但 Google 建議採用隱含流程所核發的存取憑證永遠不會過期。這是因為憑證在隱含流程到期後，必須強制重新連結帳戶。如果您需要基於安全考量而要求憑證過期，強烈建議您改用授權碼流程。

設計指南

本節說明您針對 OAuth 連結流程託管的使用者畫面設計要求和建議。在 Google 應用程式呼叫 API 後，您的平台會向使用者顯示登入 Google 頁面和帳戶連結同意畫面。使用者同意連結帳戶之後，系統就會將他們重新導向 Google 的應用程式。

必要條件

1. 您必須通知使用者的帳戶將連結至 Google，而不是特定的 Google 產品，例如 Google Home 或 Google 助理。

建議

建議您採取下列做法：

1. 顯示 Google 的隱私權政策。在同意畫面中加入 Google 隱私權政策連結。

2. 要分享的資料。使用簡明扼要的用詞告訴使用者 Google 需要哪些資料，以及收集這些資料的原因。

3. 加入明確的行動號召。在同意畫面上註明明確的行動號召 (例如「同意和連結」)。這是因為使用者必須瞭解需要與 Google 分享哪些資料，才能連結自己的帳戶。

4. 取消功能：如果使用者選擇不要進行連結，可以提供取消或取消訂閱的方式。

5. 清除登入程序。確保使用者明確能登入 Google 帳戶，例如使用者名稱和密碼欄位或使用 Google 帳戶登入欄位。

6. 取消連結。提供機制，讓使用者能取消連結，例如 您平台中帳戶設定的網址。您也可以加入 Google 帳戶連結，方便使用者管理已連結帳戶。

7. 可變更使用者帳戶。建議使用者切換帳戶的方法。如果使用者經常擁有多個帳戶，這項功能就特別實用。

   • 如果使用者必須先關閉同意畫面才能切換帳戶，請將可復原的錯誤傳送給 Google，讓使用者可透過 OAuth 連結和隱含流程登入所需帳戶。

8. 加入您的標誌。在同意畫面中顯示公司標誌。 請善用樣式指南來放置標誌。如果您希望一併顯示 Google 的標誌，請參閱標誌和商標一文。

Create the project

To create your project to use account linking:

1. Go to the Google API Console.
2. 單擊創建項目 。
3. 輸入名稱或接受生成的建議。
4. 確認或編輯所有剩餘字段。
5. 點擊創建 。

要查看您的項目ID：

1. Go to the Google API Console.
2. 在登錄頁面的表格中找到您的項目。項目ID出現在ID列中。

Configure your OAuth Consent Screen

The Google Account Linking process includes a consent screen which tells users the application requesting access to their data, what kind of data they are asking for and the terms that apply. You will need to configure your OAuth consent screen before generating a Google API client ID.

1. Open the OAuth consent screen page of the Google APIs console.
2. If prompted, select the project you just created.

3. On the "OAuth consent screen" page, fill out the form and click the “Save” button.

   Application name: The name of the application asking for consent. The name should accurately reflect your application and be consistent with the application name users see elsewhere. The application name will be shown on the Account Linking consent screen.

   Application logo: An image on the consent screen that will help users recognize your app. The logo is shown on Account linking consent screen and on account settings

   Support email: For users to contact you with questions about their consent.

   Scopes for Google APIs: Scopes allow your application to access your user's private Google data. For the Google Account Linking use case, default scope (email, profile, openid) is sufficient, you don’t need to add any sensitive scopes. It is generally a best practice to request scopes incrementally, at the time access is required, rather than up front. Learn more.

   Authorized domains: To protect you and your users, Google only allows applications that authenticate using OAuth to use Authorized Domains. Your applications' links must be hosted on Authorized Domains. Learn more.

   Application Homepage link: Home page for your application. Must be hosted on an Authorized Domain.

   Application Privacy Policy link: Shown on Google Account Linking consent screen. Must be hosted on an Authorized Domain.

   Application Terms of Service link (Optional): Must be hosted on an Authorized Domain.

   

   Figure 1. Google Account Linking Consent Screen for a fictitious Application, Tunery

4. Check "Verification Status", if your application needs verification then click the "Submit For Verification" button to submit your application for verification. Refer to OAuth verification requirements for details.

實作 OAuth 伺服器

To support the OAuth 2.0 implicit flow, your service makes an authorization endpoint available by HTTPS. This endpoint is responsible for authentication and obtaining consent from users for data access. The authorization endpoint presents a sign-in UI to your users that aren't already signed in and records consent to the requested access.

When a Google application needs to call one of your service's authorized APIs, Google uses this endpoint to get permission from your users to call these APIs on their behalf.

A typical OAuth 2.0 implicit flow session initiated by Google has the following flow:

1. Google opens your authorization endpoint in the user's browser. The user signs in, if not signed in already, and grants Google permission to access their data with your API, if they haven't already granted permission.
2. Your service creates an access token and returns it to Google. To do so, redirect the user's browser back to Google with the access token attached to the request.
3. Google calls your service's APIs and attaches the access token with each request. Your service verifies that the access token grants Google authorization to access the API and then completes the API call.

Handle authorization requests

When a Google application needs to perform account linking via an OAuth 2.0 implicit flow, Google sends the user to your authorization endpoint with a request that includes the following parameters:

Authorization endpoint parameters
client_id	The client ID you assigned to Google.
redirect_uri	The URL to which you send the response to this request.
state	A bookkeeping value that is passed back to Google unchanged in the redirect URI.
response_type	The type of value to return in the response. For the OAuth 2.0 implicit flow, the response type is always token.
user_locale	The Google Account language setting in RFC5646 format used to localize your content in the user's preferred language.

For example, if your authorization endpoint is available at https://myservice.example.com/auth, a request might look like the following:

GET https://myservice.example.com/auth?client_id=GOOGLE_CLIENT_ID&redirect_uri=REDIRECT_URI&state=STATE_STRING&response_type=token&user_locale=LOCALE

For your authorization endpoint to handle sign-in requests, do the following steps:

1. Verify the client_id and redirect_uri values to prevent granting access to unintended or misconfigured client apps:

   • Confirm that the client_id matches the client ID you assigned to Google.
   • Confirm that the URL specified by the redirect_uri parameter has the following form:

     https://oauth-redirect.googleusercontent.com/r/YOUR_PROJECT_ID
     https://oauth-redirect-sandbox.googleusercontent.com/r/YOUR_PROJECT_ID
     

2. Check if the user is signed in to your service. If the user isn't signed in, complete your service's sign-in or sign-up flow.

3. Generate an access token for Google to use to access your API. The access token can be any string value, but it must uniquely represent the user and the client the token is for and must not be guessable.

4. Send an HTTP response that redirects the user's browser to the URL specified by the redirect_uri parameter. Include all of the following parameters in the URL fragment:

   • access_token: The access token you just generated
   • token_type: The string bearer
   • state: The unmodified state value from the original request

   The following is an example of the resulting URL:

   https://oauth-redirect.googleusercontent.com/r/YOUR_PROJECT_ID#access_token=ACCESS_TOKEN&token_type=bearer&state=STATE_STRING

Google's OAuth 2.0 redirect handler receives the access token and confirms that the state value hasn't changed. After Google has obtained an access token for your service, Google attaches the token to subsequent calls to your service APIs.

處理用戶信息請求

該用戶信息終端是一個OAuth 2.0保護的資源，對鏈接的用戶返回的權利要求。實現和託管 userinfo 端點是可選的，以下用例除外：

• 鏈接帳戶登錄與谷歌一個水龍頭。
• 無摩擦訂閱的AndroidTV。

從您的令牌端點成功檢索訪問令牌後，Google 會向您的 userinfo 端點發送請求，以檢索有關鏈接用戶的基本個人資料信息。

userinfo 端點請求標頭
Authorization header	Bearer 類型的訪問令牌。

例如，如果你的用戶信息終端可在https://myservice.example.com/userinfo ，請求看起來像下面這樣：

GET /userinfo HTTP/1.1
Host: myservice.example.com
Authorization: Bearer ACCESS_TOKEN

要讓您的 userinfo 端點處理請求，請執行以下步驟：

1. 從 Authorization 標頭中提取訪問令牌並返回與訪問令牌關聯的用戶的信息。
2. 如果訪問令牌無效，返回HTTP 401錯誤未經授權使用的WWW-Authenticate響應頭。下面是一個userinfo的錯誤響應的一個示例：

   HTTP/1.1 401 Unauthorized
   WWW-Authenticate: error="invalid_token",
   error_description="The Access Token expired"
   

   如果一個401未經授權，或任何其它不成功錯誤響應在關聯過程返回時，誤差將是不可恢復的，所檢索的令牌將被丟棄，並且用戶將必須再次啟動鏈接過程。

3. 如果訪問令牌是有效的，回國與以下JSON對象在HTTPS響應的身體HTTP 200回應：

   {
   "sub": "USER_UUID",
   "email": "EMAIL_ADDRESS",
   "given_name": "FIRST_NAME",
   "family_name": "LAST_NAME",
   "name": "FULL_NAME",
   "picture": "PROFILE_PICTURE",
   }
   

   如果你的用戶信息端點返回一個HTTP 200成功響應，檢索到的令牌和索賠登記針對用戶的谷歌帳戶。

   用戶信息端點響應
   sub	標識系統中用戶的唯一 ID。
   email	用戶的電子郵件地址。
   given_name	可選：用戶的名字。
   family_name	可選：用戶的姓氏。
   name	可選：用戶的全名。
   picture	可選：用戶的檔案圖片。

驗證實作

You can validate your implementation by using the OAuth 2.0 Playground tool.

In the tool, do the following steps:

1. Click Configuration settings to open the OAuth 2.0 Configuration window.
2. In the OAuth flow field, select Client-side.
3. In the OAuth Endpoints field, select Custom.
4. Specify your OAuth 2.0 endpoint and the client ID you assigned to Google in the corresponding fields.
5. In the Step 1 section, don't select any Google scopes. Instead, leave this field blank or type a scope valid for your server (or an arbitrary string if you don't use OAuth scopes). When you're done, click Authorize APIs.
6. In the Step 2 and Step 3 sections, go through the OAuth 2.0 flow and verify that each step works as intended.

You can validate your implementation by using the Google Account Linking Demo tool.

In the tool, do the following steps:

1. Click the Sign-in with Google button.
2. Choose the account you'd like to link.
3. Enter the service ID.
4. Optionally enter one or more scopes that you will request access for.
5. Click Start Demo.
6. When prompted, confirm that you may consent and deny the linking request.
7. Confirm that you are redirected to your platform.