Liên kết Tài khoản Google với OAuth

Các tài khoản được liên kết bằng quy trình mã uỷ quyền OAuth 2.0 theo tiêu chuẩn ngành.

OAuth 2.1 và PKCE cho nhân viên hỗ trợ

Đối với các tác nhân AI không trạng thái và quy trình đa phương thức, bạn nên thực thi OAuth 2.1.

• PKCE (Khoá bằng chứng để trao đổi mã): Phải được dùng để bảo mật quy trình sử dụng mã uỷ quyền, ngăn chặn các cuộc tấn công chặn.
• Không có luồng cấp quyền trực tiếp: Luồng cấp quyền trực tiếp cho phép hiển thị mã truy cập trong URL, đây là một rủi ro bảo mật đối với môi trường tác nhân.

Dịch vụ của bạn phải hỗ trợ các điểm cuối uỷ quyền và trao đổi mã thông báo tuân thủ OAuth 2.0/2.1.

Lưu ý: Luồng cấp quyền trực tiếp không còn được dùng và không còn được hỗ trợ cho các quy trình tích hợp mới. Nếu bạn đang duy trì một chế độ tích hợp luồng cấp quyền trực tiếp hiện có, hãy xem tài liệu [Luồng cấp quyền trực tiếp được lưu trữ](/identity/account-linking/archive/implicit-flow).

Create the project

Note: You can reuse an existing project and do not need to create a new project primarily for account linking.

To create your project to use account linking:

1. Go to the Google API Console.
2. Click Create project.
3. Enter a name or accept the generated suggestion.
4. Confirm or edit any remaining fields.
5. Click Create.

To view your project ID:

1. Go to the Google API Console.
2. Find your project in the table on the landing page. The project ID appears in the ID column.

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.

Triển khai máy chủ OAuth

An OAuth 2.0 server implementation of the authorization code flow consists of two endpoints, which your service makes available by HTTPS. The first endpoint is the authorization endpoint, which is responsible for finding or 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. The second endpoint is the token exchange endpoint, which is used to obtain encrypted strings, called tokens, that authorize a user to access your service.

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

Google Account Linking: OAuth Authorization Code Flow

The following sequence diagram details interactions between the User, Google, and your service's endpoints.

Figure 1. The sequence of events in the OAuth 2.0 Authorization Code flow for Google Account Linking.

Roles and responsibilities

The following table defines the roles and responsibilities of the actors in the Google Account Linking (GAL) OAuth flow. Note that in GAL, Google acts as the OAuth Client, while your service acts as the Identity/Service Provider.

Actor / Component	GAL Role	Responsibilities
Google App / Server	OAuth Client	Initiates the flow, receives the authorization code, exchanges it for tokens, and securely stores them to access your service's APIs.
Your Authorization Endpoint	Authorization Server	Authenticates your users and obtains their consent to share access to their data with Google.
Your Token Exchange Endpoint	Authorization Server	Validates authorization codes and refresh tokens, and issues access tokens to the Google Server.
Google Redirect URI	Callback Endpoint	Receives the user redirect from your authorization service with the code and state values.

An OAuth 2.0 authorization code flow session initiated by Google has the following flow:

1. Google opens your authorization endpoint in the user's browser. If the flow started on a voice-only device for an Action, Google transfers the execution to a phone.
2. 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.
3. Your service creates an authorization code and returns it to Google. To do so, redirect the user's browser back to Google with the authorization code attached to the request.
4. Google sends the authorization code to your token exchange endpoint, which verifies the authenticity of the code and returns an access token and a refresh token. The access token is a short-lived token that your service accepts as credentials to access APIs. The refresh token is a long-lived token that Google can store and use to acquire new access tokens when they expire.
5. After the user has completed the account linking flow, every subsequent request sent from Google contains an access token.

Implementation Recipe

Follow these steps to implement the Authorization Code flow.

Step 1: Handle authorization requests

When Google initiates account linking, it redirects the user to your authorization endpoint. For detailed protocol contracts and parameter requirements, see the Authorization Endpoint.

To handle the request, perform the following actions:

1. Validate the request:

   • Confirm that the client_id matches the Client ID assigned to Google.
   • Confirm that the redirect_uri matches the expected Google redirect URL: none https://oauth-redirect.googleusercontent.com/r/YOUR_PROJECT_ID https://oauth-redirect-sandbox.googleusercontent.com/r/YOUR_PROJECT_ID
   • Verify that response_type is code.

2. Authenticate the user:

   • Check if the user is signed in to your service.
   • If the user is not signed in, prompt them to complete your sign-in or sign-up flow.

3. Generate authorization code:

   • Create a unique, non-guessable authorization code associated with the user and client.
   • Set the code to expire in approximately 10 minutes.

4. Redirect back to Google:

   • Redirect the browser to the URL provided in redirect_uri.
   • Append the following query parameters:
     • code: The authorization code you generated.
     • state: The unmodified state value received from Google.

Step 2: Handle token exchange requests

Your token exchange endpoint processes two types of requests: exchanging codes for tokens, and refreshing expired access tokens. For detailed protocol contracts and parameter requirements, see the Token Exchange Endpoint.

A. Exchange authorization codes for tokens

When Google receives the authorization code, it calls your token exchange endpoint (POST) to retrieve tokens.

1. Validate the request:

   • Verify client_id and client_secret.
   • Verify the authorization code is valid and not expired.
   • Confirm redirect_uri matches the value used in Step 1.
   • If validation fails, return an HTTP 400 Bad Request with {"error": "invalid_grant"}.

2. Issue tokens:

   • Generate a long-lived refresh_token and a short-lived access_token (typically 1 hour).
   • Return an HTTP 200 OK with the standard JSON token response.

B. Refresh access tokens

When the access token expires, Google requests a new one using the refresh token.

1. Validate the request:

   • Verify client_id, client_secret, and refresh_token.
   • If validation fails, return an HTTP 400 Bad Request with {"error": "invalid_grant"}.

2. Issue new access token:

   • Generate a new short-lived access_token.
   • Return an HTTP 200 OK with the JSON token response (optionally including a new refresh token).

Handle userinfo requests

The userinfo endpoint is an OAuth 2.0 protected resource that return claims about the linked user. Implementing and hosting the userinfo endpoint is optional, except for the following use cases:

• Linked Account Sign-In with Google One Tap.
• Frictionless subscription on AndroidTV.

After the access token has been successfully retrieved from your token endpoint, Google sends a request to your userinfo endpoint to retrieve basic profile information about the linked user.

userinfo endpoint request headers
Authorization header	The access token of type Bearer.

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

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

For your userinfo endpoint to handle requests, do the following steps:

1. Extract access token from the Authorization header and return information for the user associated with the access token.
2. If the access token is invalid, return an HTTP 401 Unauthorized error with using the WWW-Authenticate Response Header. Below is an example of a userinfo error response:

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

   If a 401 Unauthorized, or any other unsuccessful error response is returned during the linking process, the error will be non-recoverable, the retrieved token will be discarded and the user will have to initiate the linking process again.

3. If the access token is valid, return and HTTP 200 response with the following JSON object in the body of the HTTPS response:

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

   If your userinfo endpoint returns an HTTP 200 success response, the retrieved token and claims are registered against the user's Google account.

   userinfo endpoint response
   sub	A unique ID that identifies the user in your system.
   email	Email address of the user.
   given_name	Optional: First name of the user.
   family_name	Optional: Last name of the user.
   name	Optional: Full name of the user.
   picture	Optional: Profile picture of the user.

Xác thực quá trình triển khai

Bạn có thể xác thực việc triển khai bằng cách sử dụng công cụ OAuth 2.0 Playground.

Trong công cụ này, hãy thực hiện các bước sau:

1. Nhấp vào Configuration để mở cửa sổ OAuth 2.0 Configuration (Cấu hình OAuth 2.0).
2. Trong trường OAuth flow (Quy trình OAuth), hãy chọn Client-side (Phía máy khách).
3. Trong trường OAuth Endpoints (Điểm cuối OAuth), hãy chọn Custom (Tuỳ chỉnh).
4. Chỉ định điểm cuối OAuth 2.0 và mã ứng dụng khách mà bạn đã chỉ định cho Google trong các trường tương ứng.
5. Trong phần Step 1 (Bước 1), đừng chọn phạm vi nào của Google. Thay vào đó, hãy để trống trường này hoặc nhập một phạm vi hợp lệ cho máy chủ của bạn (hoặc một chuỗi tuỳ ý nếu bạn không sử dụng phạm vi OAuth). Khi hoàn tất, hãy nhấp vào Authorize APIs (Cấp quyền cho API).
6. Trong phần Step 2 (Bước 2) và Step 3 (Bước 3), hãy thực hiện quy trình OAuth 2.0 và xác minh rằng mỗi bước đều hoạt động như dự kiến.

Bạn có thể xác thực việc triển khai bằng cách sử dụng công cụ Google Account Linking Demo.

Trong công cụ này, hãy thực hiện các bước sau:

1. Nhấp vào nút Sign in with Google (Đăng nhập bằng Google).
2. Chọn tài khoản mà bạn muốn liên kết.
3. Nhập mã dịch vụ.
4. Bạn có thể nhập một hoặc nhiều phạm vi mà bạn sẽ yêu cầu quyền truy cập.
5. Nhấp vào Start Demo (Bắt đầu bản minh hoạ).
6. Khi được nhắc, hãy xác nhận rằng bạn có thể đồng ý và từ chối yêu cầu liên kết.
7. Xác nhận rằng bạn được chuyển hướng đến nền tảng của mình.