Penautan Akun Google dengan OAuth

Akun ditautkan menggunakan alur implisit dan kode otorisasi OAuth 2.0 standar industri. Layanan Anda harus mendukung endpoint otorisasi dan pertukaran token yang mematuhi OAuth 2.0.

In the implicit flow, Google opens your authorization endpoint in the user's browser. After successful sign in, you return a long-lived access token to Google. This access token is now included in every request sent from Google.

In the authorization code flow, you need two endpoints:

  • The authorization endpoint, which presents the sign-in UI to your users that aren't already signed in. The authorization endpoint also creates a short-lived authorization code to record users' consent to the requested access.

  • The token exchange endpoint, which is responsible for two types of exchanges:

    1. Exchanges an authorization code for a long-lived refresh token and a short-lived access token. This exchange happens when the user goes through the account linking flow.
    2. Exchanges a long-lived refresh token for a short-lived access token. This exchange happens when Google needs a new access token because the one it had expired.

Choose an OAuth 2.0 flow

Although the implicit flow is simpler to implement, Google recommends that access tokens issued by the implicit flow never expire. This is because the user is forced to link their account again after a token expires with the implicit flow. If you need token expiration for security reasons, we strongly recommend that you use the authorization code flow instead.

Design guidelines

This section describes the design requirements and recommendations for the user screen that you host for OAuth linking flows. After it's called by Google's app, your platform displays a sign in to Google page and account linking consent screen to the user. The user is directed back to Google's app after giving their consent to link accounts.

This figure shows the steps for a user to link their Google account
            to your authentication system. The first screenshot shows
            user-initiated linking from your platform. The second image shows
            user sign-in to Google, while the third shows the user consent and
            confirmation for linking their Google account with your app. The
            final screenshot shows a successfully linked user account in the
            Google app.
Figure 1. Account linking user sign in to Google and consent screens.

Requirements

  1. You must communicate that the user’s account will be linked to Google, not a specific Google product like Google Home or Google Assistant.

Recommendations

We recommend that you do the following:

  1. Display Google's Privacy Policy. Include a link to Google’s Privacy Policy on the consent screen.

  2. Data to be shared. Use clear and concise language to tell the user what data of theirs Google requires and why.

  3. Clear call-to-action. State a clear call-to-action on your consent screen, such as “Agree and link.” This is because users need to understand what data they're required to share with Google to link their accounts.

  4. Ability to cancel. Provide a way for users to go back or cancel, if they choose not to link.

  5. Clear sign-in process. Ensure that users have clear method for signing in to their Google account, such as fields for their username and password or Sign in with Google.

  6. Ability to unlink. Offer a mechanism for users to unlink, such as a URL to their account settings on your platform. Alternatively, you can include a link to Google Account where users can manage their linked account.

  7. Ability to change user account. Suggest a method for users to switch their account(s). This is especially beneficial if users tend to have multiple accounts.

    • If a user must close the consent screen to switch accounts, send a recoverable error to Google so the user can sign in to the desired account with OAuth linking and the implicit flow.
  8. Include your logo. Display your company logo on the consent screen. Use your style guidelines to place your logo. If you wish to also display Google's logo, see Logos and trademarks.

Create the project

To create your project to use account linking:

  1. Go to the Google API Console.
  2. Klik Buat proyek .
  3. Masukkan nama atau terima saran yang dihasilkan.
  4. Konfirmasikan atau edit bidang yang tersisa.
  5. Klik Buat .

Untuk melihat ID proyek Anda:

  1. Go to the Google API Console.
  2. Temukan proyek Anda di tabel di halaman arahan. ID proyek muncul di kolom ID .

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

Untuk mendukung aliran implisit OAuth 2.0, layanan Anda membuat titik akhir otorisasi yang tersedia dengan HTTPS. Titik akhir ini bertanggung jawab untuk otentikasi dan memperoleh persetujuan dari pengguna untuk akses data. Titik akhir otorisasi menyajikan UI masuk ke pengguna Anda yang belum masuk dan mencatat persetujuan untuk akses yang diminta.

Saat aplikasi Google perlu memanggil salah satu API resmi layanan Anda, Google menggunakan titik akhir ini untuk mendapatkan izin dari pengguna Anda untuk memanggil API ini atas nama mereka.

Sesi alur implisit OAuth 2.0 tipikal yang diprakarsai oleh Google memiliki alur berikut:

  1. Google membuka titik akhir otorisasi Anda di browser pengguna. Pengguna masuk, jika belum masuk, dan memberikan izin kepada Google untuk mengakses data mereka dengan API Anda, jika mereka belum memberikan izin.
  2. Layanan Anda menciptakan token akses dan kembali ke Google. Untuk melakukannya, arahkan kembali browser pengguna ke Google dengan token akses yang dilampirkan pada permintaan.
  3. Google memanggil API layanan Anda dan melampirkan token akses dengan setiap permintaan. Layanan Anda memverifikasi bahwa token akses memberikan otorisasi kepada Google untuk mengakses API dan kemudian menyelesaikan panggilan API.

Menangani permintaan otorisasi

Saat aplikasi Google perlu melakukan penautan akun melalui alur implisit OAuth 2.0, Google mengirim pengguna ke titik akhir otorisasi Anda dengan permintaan yang menyertakan parameter berikut:

Parameter titik akhir otorisasi
client_id ID klien yang Anda tetapkan ke Google.
redirect_uri URL tujuan Anda mengirim tanggapan atas permintaan ini.
state Nilai pembukuan yang diteruskan kembali ke Google tidak berubah di URI pengalihan.
response_type Jenis nilai yang akan dikembalikan dalam respons. Untuk aliran implisit OAuth 2.0, jenis respon selalu token .
user_locale Akun Google pengaturan bahasa di RFC5646 format yang digunakan untuk melokalisasi konten Anda dalam bahasa pilihan pengguna.

Misalnya, jika endpoint otorisasi Anda tersedia di https://myservice.example.com/auth , permintaan akan terlihat seperti berikut ini:

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

Agar titik akhir otorisasi Anda menangani permintaan masuk, lakukan langkah-langkah berikut:

  1. Verifikasi client_id dan redirect_uri nilai-nilai untuk mencegah memberikan akses ke aplikasi client yang tidak diinginkan atau salah konfigurasi:

    • Konfirmasi bahwa client_id sesuai dengan ID klien Anda ditugaskan untuk Google.
    • Konfirmasi bahwa URL yang ditentukan oleh redirect_uri parameter memiliki bentuk sebagai berikut:
      https://oauth-redirect.googleusercontent.com/r/YOUR_PROJECT_ID
      https://oauth-redirect-sandbox.googleusercontent.com/r/YOUR_PROJECT_ID
      
  2. Periksa apakah pengguna masuk ke layanan Anda. Jika pengguna tidak masuk, selesaikan alur masuk atau pendaftaran layanan Anda.

  3. Buat token akses untuk digunakan Google untuk mengakses API Anda. Token akses dapat berupa nilai string apa pun, tetapi harus secara unik mewakili pengguna dan klien yang menjadi tujuan token dan tidak boleh ditebak.

  4. Kirim respon HTTP yang mengarahkan browser pengguna ke URL yang ditentukan oleh redirect_uri parameter. Sertakan semua parameter berikut dalam fragmen URL:

    • access_token : Akses Token Anda hanya dihasilkan
    • token_type : String bearer
    • state : The dimodifikasi nilai negara dari permintaan asli

    Berikut ini adalah contoh dari URL yang dihasilkan:

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

Google OAuth 2.0 redirect handler menerima akses token dan menegaskan bahwa state nilai tidak berubah. Setelah Google memperoleh token akses untuk layanan Anda, Google melampirkan token ke panggilan berikutnya ke API layanan Anda.

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:

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.

Memvalidasi implementasi

Anda dapat memvalidasi implementasi Anda dengan menggunakan OAuth 2.0 Playground alat.

Pada alat, lakukan langkah-langkah berikut:

  1. Klik Konfigurasi untuk membuka jendela Configuration OAuth 2.0.
  2. Di bidang aliran OAuth, pilih Client-side.
  3. Di bidang OAuth endpoint, pilih Custom.
  4. Tentukan titik akhir OAuth 2.0 dan ID klien yang Anda tetapkan ke Google di bidang yang sesuai.
  5. Pada bagian Langkah 1, tidak memilih lingkup Google. Sebagai gantinya, biarkan bidang ini kosong atau ketik cakupan yang valid untuk server Anda (atau string arbitrer jika Anda tidak menggunakan cakupan OAuth). Setelah selesai, klik Otorisasi API.
  6. Dalam Langkah 2 dan Langkah 3 bagian, melalui aliran OAuth 2.0 dan memverifikasi bahwa setiap langkah bekerja sebagaimana dimaksud.

Anda dapat memvalidasi implementasi Anda dengan menggunakan Akun Google Menghubungkan Demo alat.

Pada alat, lakukan langkah-langkah berikut:

  1. Klik Sign-in dengan tombol 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. Saat diminta, konfirmasikan bahwa Anda dapat menyetujui dan menolak permintaan penautan.
  7. Konfirmasikan bahwa Anda dialihkan ke platform Anda.