Penautan Akun Google dengan OAuth

Akun ditautkan menggunakan alur kode otorisasi OAuth 2.0 standar industri.

OAuth 2.1 &PKCE untuk Agen

Untuk agen AI tanpa status dan pipeline multi-modal, sebaiknya terapkan OAuth 2.1.

• PKCE (Proof Key for Code Exchange): Harus digunakan untuk mengamankan alur kode otorisasi, sehingga mencegah serangan intersepsi.
• Tidak Ada Alur Implisit: Alur implisit mengekspos token akses di URL, yang merupakan risiko keamanan untuk lingkungan agen.

Layanan Anda harus mendukung endpoint pertukaran token dan otorisasi yang sesuai dengan OAuth 2.0/2.1.

Create the project

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.

Mengimplementasikan server 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.

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.

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).

Menangani permintaan info pengguna

Endpoint userinfo adalah resource yang dilindungi OAuth 2.0 yang menampilkan klaim tentang pengguna yang ditautkan. Menerapkan dan menghosting endpoint userinfo bersifat opsional, kecuali untuk kasus penggunaan berikut:

• Login dengan Akun Tertaut dengan Google One Ketuk.
• Langganan tanpa hambatan di Android TV.

Setelah token akses berhasil diambil dari endpoint token Anda, Google akan mengirimkan permintaan ke endpoint userinfo Anda untuk mengambil informasi profil dasar tentang pengguna yang ditautkan.

Misalnya, jika endpoint userinfo Anda tersedia di https://myservice.example.com/userinfo, permintaan mungkin akan terlihat seperti berikut:

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

Agar endpoint userinfo Anda dapat menangani permintaan, lakukan langkah-langkah berikut:

1. Ekstrak token akses dari header Otorisasi dan tampilkan informasi untuk pengguna yang terkait dengan token akses.
2. Jika token akses tidak valid, tampilkan error HTTP 401 Tidak Sah dengan menggunakan Header Respons WWW-Authenticate. Berikut adalah contoh respons error userinfo:

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

   Jika pesan error 401 Tidak Sah, atau respons error lainnya yang tidak berhasil ditampilkan selama proses penautan, error tersebut tidak akan dapat dipulihkan, token yang diambil akan dihapus dan pengguna harus memulai proses penautan lagi.

3. Jika token akses valid, tampilkan dan respons HTTP 200 dengan objek JSON berikut dalam isi HTTPS respons:

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

   Jika endpoint userinfo Anda menampilkan respons sukses HTTP 200, token dan klaim yang diambil akan didaftarkan terhadap Akun Google pengguna.

   respons endpoint userinfo
   sub	ID unik yang mengidentifikasi pengguna di sistem Anda.
   email	Alamat email pengguna.
   given_name	Opsional: Nama depan pengguna.
   family_name	Opsional: Nama belakang pengguna.
   name	Opsional: Nama lengkap pengguna.
   picture	Opsional: Foto profil pengguna.

Memvalidasi implementasi

Anda dapat memvalidasi penerapan dengan menggunakan alat OAuth 2.0 Playground.

Di alat, lakukan langkah-langkah berikut:

1. Klik Konfigurasi settings untuk membuka jendela Konfigurasi OAuth 2.0.
2. Di kolom OAuth flow, pilih Client-side.
3. Di kolom OAuth Endpoints, pilih Custom.
4. Tentukan endpoint OAuth 2.0 dan client ID yang Anda tetapkan ke Google di kolom yang sesuai.
5. Di bagian Langkah 1, jangan pilih cakupan Google apa pun. Sebagai gantinya, biarkan kolom ini kosong atau ketik cakupan yang valid untuk server Anda (atau string arbitrer jika Anda tidak menggunakan cakupan OAuth). Setelah selesai, klik Izinkan API.
6. Di bagian Langkah 2 dan Langkah 3, ikuti alur OAuth 2.0 dan verifikasi bahwa setiap langkah berfungsi sebagaimana mestinya.

Anda dapat memvalidasi penerapan dengan menggunakan alat Demo Penautan Akun Google.

Di alat, lakukan langkah-langkah berikut:

1. Klik tombol Login dengan Google.
2. Pilih akun yang ingin Anda tautkan.
3. Masukkan ID layanan.
4. Secara opsional, masukkan satu atau beberapa cakupan yang akan Anda minta aksesnya.
5. Klik Mulai Demo.
6. Jika diminta, konfirmasi bahwa Anda dapat menyetujui dan menolak permintaan penautan.
7. Konfirmasi bahwa Anda dialihkan ke platform Anda.