Optimierte Verknüpfung mit OAuth und Google Log-in

Übersicht

Optimierte Verknüpfung mit OAuth-basiertem Google Log-in: Google Log-in ergänzt OAuth-Verknüpfung. Dies ermöglicht eine nahtlose Verknüpfung von .

Um Kontoverknüpfungen mit OAuth und Google Log-in durchzuführen, folge diesen allgemeinen Schritte:

  1. Bitten Sie den Nutzer zuerst, seine Einwilligung für den Zugriff auf sein Google-Profil zu geben.
  2. Anhand der Informationen in ihrem Profil können Sie prüfen, ob das Nutzerkonto vorhanden ist.
  3. Verknüpfen Sie die Konten für bestehende Nutzer.
  4. Wenn Sie in Ihrem Authentifizierungssystem keine Übereinstimmung für den Google-Nutzer finden können, Validieren Sie das von Google erhaltene ID-Token. Sie können dann ein nutzerbasiertes zu den Profilinformationen im ID-Token.
Diese Abbildung zeigt, wie ein Nutzer sein Google-Konto mithilfe des optimierten Verknüpfungsvorgangs verknüpft. Der erste Screenshot zeigt, wie Nutzer Ihre App für die Verknüpfung auswählen können. Auf dem zweiten Screenshot kann der Nutzer überprüfen, ob er bereits ein Konto bei Ihrem Dienst hat. Auf dem dritten Screenshot kann der Nutzer das Google-Konto auswählen, mit dem er eine Verknüpfung herstellen möchte. Der vierte Screenshot zeigt die Bestätigung für die Verknüpfung des Google-Kontos mit Ihrer App. Der fünfte Screenshot zeigt ein erfolgreich verknüpftes Nutzerkonto in der Google App.

Abbildung 1. Kontoverknüpfung auf dem Smartphone eines Nutzers mit der optimierten Verknüpfung

Anforderungen für optimierte Verknüpfungen

OAuth-Server implementieren

Der Endpunkt des Tokenaustauschs muss die Intents check, create und get unterstützen. Unten sehen Sie die Schritte, die während der Kontoverknüpfung ausgeführt werden, und es wird angegeben, wann die verschiedenen Intents aufgerufen werden:

  1. Hat der Nutzer ein Konto in Ihrem Authentifizierungssystem? (Der Nutzer entscheidet sich mit Ja oder NEIN.) <ph type="x-smartling-placeholder">
      </ph>
    1. JA : Nutzt der Nutzer die E-Mail-Adresse, die mit seinem Google-Konto verknüpft ist, um sich auf Ihrer Plattform anzumelden? (Der Nutzer entscheidet sich mit Ja oder NEIN.) <ph type="x-smartling-placeholder">
        </ph>
      1. JA : Verfügt der Nutzer über ein übereinstimmendes Konto in Ihrem Authentifizierungssystem? (check intent wird zur Bestätigung aufgerufen) <ph type="x-smartling-placeholder">
          </ph>
        1. JA : get intent wird aufgerufen und das Konto wird verknüpft, wenn der get-Intent erfolgreich zurückgegeben wird.
        2. NEIN : Neues Konto erstellen? (Der Nutzer entscheidet sich mit Ja oder NEIN.) <ph type="x-smartling-placeholder">
            </ph>
          1. JA : create intent wird aufgerufen und das Konto verknüpft, wenn der Erstellungs-Intent erfolgreich zurückgegeben wird.
          2. NEIN : Der Web-OAuth-Ablauf wird ausgelöst, der Nutzer wird zu seinem Browser weitergeleitet und erhält die Möglichkeit, eine Verknüpfung mit einer anderen E-Mail-Adresse herzustellen.
      2. NEIN : Der Web-OAuth-Vorgang wird ausgelöst, der Nutzer wird zu seinem Browser weitergeleitet und hat die Möglichkeit, eine Verknüpfung mit einer anderen E-Mail-Adresse herzustellen.
    2. NEIN : Verfügt der Nutzer über ein übereinstimmendes Konto in Ihrem Authentifizierungssystem? (check intent wird zur Bestätigung aufgerufen) <ph type="x-smartling-placeholder">
        </ph>
      1. JA : get intent wird aufgerufen und das Konto wird verknüpft, wenn der get-Intent erfolgreich zurückgegeben wird.
      2. NEIN : create intent wird aufgerufen und das Konto verknüpft, wenn die Rückgabe des Intents zum Erstellen erfolgreich ist.

Check for an existing user account (check intent)

After the user gives consent to access their Google profile, Google sends a request that contains a signed assertion of the Google user's identity. The assertion contains information that includes the user's Google Account ID, name, and email address. The token exchange endpoint configured for your project handles that request.

If the corresponding Google account is already present in your authentication system, your token exchange endpoint responds with account_found=true. If the Google account doesn't match an existing user, your token exchange endpoint returns an HTTP 404 Not Found error with account_found=false.

The request has the following form:

POST /token HTTP/1.1
Host: oauth2.example.com
Content-Type: application/x-www-form-urlencoded

grant_type=urn:ietf:params:oauth:grant-type:jwt-bearer&intent=check&assertion=JWT&scope=SCOPES&client_id=GOOGLE_CLIENT_ID&client_secret=GOOGLE_CLIENT_SECRET

Your token exchange endpoint must be able to handle the following parameters:

Token endpoint parameters
intent For these requests, the value of this parameter is check.
grant_type The type of token being exchanged. For these requests, this parameter has the value urn:ietf:params:oauth:grant-type:jwt-bearer.
assertion A JSON Web Token (JWT) that provides a signed assertion of the Google user's identity. The JWT contains information that includes the user's Google Account ID, name, and email address.
client_id The client ID you assigned to Google.
client_secret The client secret you assigned to Google.

To respond to the check intent requests, your token exchange endpoint must perform the following steps:

  • Validate and decode the JWT assertion.
  • Check if the Google account is already present in your authentication system.
Validate and decode the JWT assertion

You can validate and decode the JWT assertion by using a JWT-decoding library for your language. Use Google's public keys, available in JWK or PEM formats, to verify the token's signature.

When decoded, the JWT assertion looks like the following example:

{
  "sub": "1234567890",      // The unique ID of the user's Google Account
  "iss": "https://accounts.google.com",        // The assertion's issuer
  "aud": "123-abc.apps.googleusercontent.com", // Your server's client ID
  "iat": 233366400,         // Unix timestamp of the assertion's creation time
  "exp": 233370000,         // Unix timestamp of the assertion's expiration time
  "name": "Jan Jansen",
  "given_name": "Jan",
  "family_name": "Jansen",
  "email": "jan@gmail.com", // If present, the user's email address
  "email_verified": true,   // true, if Google has verified the email address
  "hd": "example.com",      // If present, the host domain of the user's GSuite email address
                            // If present, a URL to user's profile picture
  "picture": "https://lh3.googleusercontent.com/a-/AOh14GjlTnZKHAeb94A-FmEbwZv7uJD986VOF1mJGb2YYQ",
  "locale": "en_US"         // User's locale, from browser or phone settings
}

In addition to verifying the token's signature, verify that the assertion's issuer (iss field) is https://accounts.google.com, that the audience (aud field) is your assigned client ID, and that the token has not expired (exp field).

Using the email, email_verified and hd fields you can determine if Google hosts and is authoritative for an email address. In cases where Google is authoritative the user is currently known to be the legitimate account owner and you may skip password or other challenges methods. Otherwise, these methods can be used to verify the account prior to linking.

Cases where Google is authoritative:

  • email has a @gmail.com suffix, this is a Gmail account.
  • email_verified is true and hd is set, this is a G Suite account.

Users may register for Google Accounts without using Gmail or G Suite. When email does not contain a @gmail.com suffix and hd is absent Google is not authoritative and password or other challenge methods are recommended to verify the user. email_verified can also be true as Google initially verified the user when the Google account was created, however ownership of the third party email account may have since changed.

Check if the Google account is already present in your authentication system

Check whether either of the following conditions are true:

  • The Google Account ID, found in the assertion's sub field, is in your user database.
  • The email address in the assertion matches a user in your user database.

If either condition is true, the user has already signed up. In that case, return a response like the following:

HTTP/1.1 200 Success
Content-Type: application/json;charset=UTF-8

{
  "account_found":"true",
}

If neither the Google Account ID nor the email address specified in the assertion matches a user in your database, the user hasn't signed up yet. In this case, your token exchange endpoint needs to reply with a HTTP 404 error that specifies "account_found": "false", as in the following example:

HTTP/1.1 404 Not found
Content-Type: application/json;charset=UTF-8

{
  "account_found":"false",
}

Handle automatic linking (get intent)

After the user gives consent to access their Google profile, Google sends a request that contains a signed assertion of the Google user's identity. The assertion contains information that includes the user's Google Account ID, name, and email address. The token exchange endpoint configured for your project handles that request.

If the corresponding Google Account is already present in your authentication system, your token exchange endpoint returns a token for the user. If the Google Account doesn't match an existing user, your token exchange endpoint returns a linking_error error and optional login_hint.

The request has the following form:

POST /token HTTP/1.1
Host: oauth2.example.com
Content-Type: application/x-www-form-urlencoded

grant_type=urn:ietf:params:oauth:grant-type:jwt-bearer&intent=get&assertion=JWT&scope=SCOPES&client_id=GOOGLE_CLIENT_ID&client_secret=GOOGLE_CLIENT_SECRET

Your token exchange endpoint must be able to handle the following parameters:

Token endpoint parameters
intent For these requests, the value of this parameter is get.
grant_type The type of token being exchanged. For these requests, this parameter has the value urn:ietf:params:oauth:grant-type:jwt-bearer.
assertion A JSON Web Token (JWT) that provides a signed assertion of the Google user's identity. The JWT contains information that includes the user's Google Account ID, name, and email address.
scope Optional: Any scopes that you've configured Google to request from users.
client_id The client ID you assigned to Google.
client_secret The client secret you assigned to Google.

To respond to the get intent requests, your token exchange endpoint must perform the following steps:

  • Validate and decode the JWT assertion.
  • Check if the Google account is already present in your authentication system.
Validate and decode the JWT assertion

You can validate and decode the JWT assertion by using a JWT-decoding library for your language. Use Google's public keys, available in JWK or PEM formats, to verify the token's signature.

When decoded, the JWT assertion looks like the following example:

{
  "sub": "1234567890",      // The unique ID of the user's Google Account
  "iss": "https://accounts.google.com",        // The assertion's issuer
  "aud": "123-abc.apps.googleusercontent.com", // Your server's client ID
  "iat": 233366400,         // Unix timestamp of the assertion's creation time
  "exp": 233370000,         // Unix timestamp of the assertion's expiration time
  "name": "Jan Jansen",
  "given_name": "Jan",
  "family_name": "Jansen",
  "email": "jan@gmail.com", // If present, the user's email address
  "email_verified": true,   // true, if Google has verified the email address
  "hd": "example.com",      // If present, the host domain of the user's GSuite email address
                            // If present, a URL to user's profile picture
  "picture": "https://lh3.googleusercontent.com/a-/AOh14GjlTnZKHAeb94A-FmEbwZv7uJD986VOF1mJGb2YYQ",
  "locale": "en_US"         // User's locale, from browser or phone settings
}

In addition to verifying the token's signature, verify that the assertion's issuer (iss field) is https://accounts.google.com, that the audience (aud field) is your assigned client ID, and that the token has not expired (exp field).

Using the email, email_verified and hd fields you can determine if Google hosts and is authoritative for an email address. In cases where Google is authoritative the user is currently known to be the legitimate account owner and you may skip password or other challenges methods. Otherwise, these methods can be used to verify the account prior to linking.

Cases where Google is authoritative:

  • email has a @gmail.com suffix, this is a Gmail account.
  • email_verified is true and hd is set, this is a G Suite account.

Users may register for Google Accounts without using Gmail or G Suite. When email does not contain a @gmail.com suffix and hd is absent Google is not authoritative and password or other challenge methods are recommended to verify the user. email_verified can also be true as Google initially verified the user when the Google account was created, however ownership of the third party email account may have since changed.

Check if the Google account is already present in your authentication system

Check whether either of the following conditions are true:

  • The Google Account ID, found in the assertion's sub field, is in your user database.
  • The email address in the assertion matches a user in your user database.

If an account is found for the user, issue an access token and return the values in a JSON object in the body of your HTTPS response, like in the following example:

{
  "token_type": "Bearer",
  "access_token": "ACCESS_TOKEN",

  "refresh_token": "REFRESH_TOKEN",

  "expires_in": SECONDS_TO_EXPIRATION
}

In some cases, account linking based on ID token might fail for the user. If it does so for any reason, your token exchange endpoint needs to reply with a HTTP 401 error that specifies error=linking_error, as the following example shows:

HTTP/1.1 401 Unauthorized
Content-Type: application/json;charset=UTF-8

{
  "error":"linking_error",
  "login_hint":"foo@bar.com"
}

When Google receives a 401 error response with linking_error, Google sends the user to your authorization endpoint with login_hint as a parameter. The user completes account linking using the OAuth linking flow in their browser.

通过 Google 登录功能处理账号创建(创建 intent)

当用户需要在您的服务中创建账号时,Google 会发出请求 发送到指定 intent=create 的令牌交换端点。

请求的格式如下:

POST /token HTTP/1.1
Host: oauth2.example.com
Content-Type: application/x-www-form-urlencoded

response_type=token&grant_type=urn:ietf:params:oauth:grant-type:jwt-bearer&scope=SCOPES&intent=create&assertion=JWT&client_id=GOOGLE_CLIENT_ID&client_secret=GOOGLE_CLIENT_SECRET

您的令牌交换端点必须能够处理以下参数:

令牌端点参数
intent 对于这些请求,此参数的值为 create
grant_type 所交换的令牌的类型。对于这类请求 参数的值为 urn:ietf:params:oauth:grant-type:jwt-bearer
assertion 一个 JSON Web 令牌 (JWT),提供 Google 用户身份。JWT 包含的信息包括用户 Google 账号 ID、姓名和电子邮件地址。
client_id 您分配给 Google 的客户 ID。
client_secret 您分配给 Google 的客户端密钥。

assertion 参数中的 JWT 包含用户的 Google 账号 ID。 姓名和电子邮件地址,可用于在 Gmail 中创建新账号 服务。

如需响应 create intent 请求,您的令牌交换端点必须执行以下步骤:

  • 验证和解码 JWT 断言。
  • 验证用户信息并创建新账号。
Validate and decode the JWT assertion

You can validate and decode the JWT assertion by using a JWT-decoding library for your language. Use Google's public keys, available in JWK or PEM formats, to verify the token's signature.

When decoded, the JWT assertion looks like the following example:

{
  "sub": "1234567890",      // The unique ID of the user's Google Account
  "iss": "https://accounts.google.com",        // The assertion's issuer
  "aud": "123-abc.apps.googleusercontent.com", // Your server's client ID
  "iat": 233366400,         // Unix timestamp of the assertion's creation time
  "exp": 233370000,         // Unix timestamp of the assertion's expiration time
  "name": "Jan Jansen",
  "given_name": "Jan",
  "family_name": "Jansen",
  "email": "jan@gmail.com", // If present, the user's email address
  "email_verified": true,   // true, if Google has verified the email address
  "hd": "example.com",      // If present, the host domain of the user's GSuite email address
                            // If present, a URL to user's profile picture
  "picture": "https://lh3.googleusercontent.com/a-/AOh14GjlTnZKHAeb94A-FmEbwZv7uJD986VOF1mJGb2YYQ",
  "locale": "en_US"         // User's locale, from browser or phone settings
}

In addition to verifying the token's signature, verify that the assertion's issuer (iss field) is https://accounts.google.com, that the audience (aud field) is your assigned client ID, and that the token has not expired (exp field).

Using the email, email_verified and hd fields you can determine if Google hosts and is authoritative for an email address. In cases where Google is authoritative the user is currently known to be the legitimate account owner and you may skip password or other challenges methods. Otherwise, these methods can be used to verify the account prior to linking.

Cases where Google is authoritative:

  • email has a @gmail.com suffix, this is a Gmail account.
  • email_verified is true and hd is set, this is a G Suite account.

Users may register for Google Accounts without using Gmail or G Suite. When email does not contain a @gmail.com suffix and hd is absent Google is not authoritative and password or other challenge methods are recommended to verify the user. email_verified can also be true as Google initially verified the user when the Google account was created, however ownership of the third party email account may have since changed.

验证用户信息并创建新账号

请检查以下任一条件是否成立:

  • Google 账号 ID(可在断言的 sub 字段中找到)位于您的用户中 数据库。
  • 断言中的电子邮件地址与用户数据库中的用户匹配。

如果满足上述任一条件,请提示用户关联其现有账号 与其 Google 账号关联。为此,请使用 HTTP 401 错误响应请求 该参数指定 error=linking_error 并将用户的电子邮件地址作为 login_hint。以下是示例响应:

HTTP/1.1 401 Unauthorized
Content-Type: application/json;charset=UTF-8

{
  "error":"linking_error",
  "login_hint":"foo@bar.com"
}

当 Google 收到包含 linking_error 的 401 错误响应时,会发送 使用 login_hint 作为参数将用户发送到您的授权端点。通过 用户在浏览器中使用 OAuth 关联流程完成账号关联。

如果以上两个条件都不满足,请使用相应信息创建一个新的用户账号 。新账号通常不会设置密码。时间是 建议您将 Google 登录功能添加到其他平台,以便用户 使用 Google 账号登录。或者 可以通过电子邮件向用户发送链接,启动密码恢复流程,以允许 用户设置密码,以便在其他平台上登录。

创建完成后,发出一个访问令牌 和刷新令牌 并在 HTTPS 响应的正文,如以下示例所示:

{
  "token_type": "Bearer",
  "access_token": "ACCESS_TOKEN",

  "refresh_token": "REFRESH_TOKEN",

  "expires_in": SECONDS_TO_EXPIRATION
}

Google API-Client-ID abrufen

Sie müssen Ihre Google API-Client-ID bei der Registrierung der Kontoverknüpfung angeben.

API-Client-ID über das Projekt abrufen, das Sie bei der OAuth-Verknüpfung erstellt haben Führen Sie dazu folgende Schritte aus:

  1. Öffnen Sie die Seite Anmeldedaten des Google API Console:
  2. Erstellen Sie ein Google APIs-Projekt oder wählen Sie eines aus.

    Wenn Ihr Projekt keine Client-ID für den Webanwendungstyp hat, klicken Sie auf Anmeldedaten erstellen > OAuth-Client-ID, um eine zu erstellen. Achten Sie darauf, Ihre Websitedomain im Feld Autorisierte JavaScript-Quellen ein. Wenn Sie lokale Tests oder die Entwicklung vor Ort verwenden, müssen Sie sowohl http://localhost als auch http://localhost:<port_number> in das Feld Autorisierte JavaScript-Quellen ein.

Implementierung validieren

您可以使用 OAuth 2.0 Playground 工具验证您的实现。

在该工具中,执行以下步骤:

  1. 点击配置 以打开 OAuth 2.0 配置窗口。
  2. OAuth flow 字段中,选择 Client-side(客户端)。
  3. OAuth 端点字段中,选择自定义
  4. 在相应字段中指定您的 OAuth 2.0 端点和您分配给 Google 的客户端 ID。
  5. 第 1 步部分,不要选择任何 Google 范围。请将此字段留空或输入对服务器有效的范围(如果您不使用 OAuth 范围,则可以输入任意字符串)。完成后,点击授权 API
  6. Step 2Step 3 部分中,完成 OAuth 2.0 流程,并验证每个步骤是否按预期运行。

您可以使用 Google 账号关联演示版工具验证您的实现。

在该工具中,执行以下步骤:

  1. 点击使用 Google 账号登录按钮。
  2. 选择您要关联的账号。
  3. 输入服务 ID。
  4. (可选)输入您要请求访问权限的一个或多个范围。
  5. 点击开始演示
  6. 当系统提示时,请确认您同意或拒绝关联请求。
  7. 确认您已被重定向到您的平台。