Vinculación de la cuenta de Google con OAuth

Las cuentas se vinculan mediante flujos de código implícitos y de autorización OAuth 2.0 estándar de la industria. Su servicio debe admitir la autorización compatible con OAuth 2.0 y los extremos de intercambio de tokens .

隐式流程中,Google在用户的浏览器中打开您的授权端点。成功登录后,您可以将长期访问令牌返回给Google。现在,此访问令牌包含在Google发送的每个请求中。

授权代码流中,您需要两个端点:

  • 授权端点,向尚未登录的用户显示登录UI。授权端点还创建了一个短暂的授权代码,以记录用户对所请求访问的同意。

  • 令牌交换端点,它负责两种类型的交换:

    1. 将授权代码交换为长寿命的刷新令牌和短寿命的访问令牌。当用户完成帐户链接流程时,就会发生这种交换。
    2. 将长寿命的刷新令牌交换为短寿命的访问令牌。当Google需要一个新的访问令牌(因为该令牌已过期)时,就会发生这种交换。

选择一个OAuth 2.0流程

尽管隐式流更易于实现,但Google建议隐式流发出的访问令牌永远不会过期。这是因为在令牌与隐式流一起过期之后,用户被迫再次链接其帐户。如果出于安全原因需要令牌到期,我们强烈建议您改用授权代码流。

设计准则

本部分描述了托管OAuth链接流的用户屏幕的设计要求和建议。在由Google应用程序调用后,您的平台会显示登录Google页面和用户的帐户链接同意屏幕。在同意链接帐户后,该用户将被定向回到Google的应用程序。

此图显示了用户将其Google帐户链接到您的身份验证系统的步骤。第一个屏幕截图显示了用户从您的平台启动的链接。第二张图片显示用户登录Google,第三张图片显示用户同意并确认将其Google帐户与您的应用程序关联。最终的屏幕截图显示了Google应用程序中已成功链接的用户帐户。
图1.帐户链接用户登录到Google和同意屏幕。

要求

  1. 您必须告知用户帐户将链接到Google,而不是特定的Google产品(例如Google Home或Google Assistant)。

推荐建议

我们建议您执行以下操作:

  1. 显示Google的隐私权政策。在同意屏幕上包括指向Google隐私权政策的链接。

  2. 要共享的数据。使用简洁明了的语言告诉用户Google需要提供哪些数据以及原因。

  3. 清除号召性用语。在您的同意屏幕上注明明确的号召性用语,例如“同意并链接”。这是因为用户需要了解与Google共享帐户链接所需的数据。

  4. 取消的能力。如果用户选择不链接,则为用户提供返回或取消的方式。

  5. 清除登录过程。确保用户使用清晰的方法登录自己的Google帐户,例如用户名和密码或使用Google登录字段。

  6. 取消链接的能力。为用户提供取消链接的机制,例如指向其平台上的帐户设置的URL。或者,您可以包含指向Google帐户的链接,用户可以在其中管理其链接的帐户。

  7. 能够更改用户帐户。建议用户切换帐户的方法。如果用户倾向于拥有多个帐户,这将特别有益。

    • 如果用户必须关闭同意屏幕才能切换帐户,请向Google发送可恢复的错误,以便用户可以使用OAuth链接隐式流程登录所需的帐户。
  8. 包括您的徽标。在同意屏幕上显示您的公司徽标。使用样式准则放置徽标。如果您还希望显示Google的徽标,请参阅徽标和商标

Create the project

To create your project to use account linking:

  1. Go to the Google API Console.
  2. Haz clic en Crear proyecto .
  3. Ingrese un nombre o acepte la sugerencia generada.
  4. Confirme o edite los campos restantes.
  5. Haz clic en Crear .

Para ver su ID de proyecto:

  1. Go to the Google API Console.
  2. Encuentra tu proyecto en la tabla de la página de inicio. El ID del proyecto aparece en la columna 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 Acount 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.

Implemente su servidor 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.

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.

Handle authorization requests

When you need to perform account linking using the OAuth 2.0 authorization code 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.
scope Optional: A space-delimited set of scope strings that specify the data Google is requesting authorization for.
response_type The type of value to return in the response. For the OAuth 2.0 authorization code flow, the response type is always code.
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&scope=REQUESTED_SCOPES&response_type=code&user_locale=LOCALE

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

  1. Verify that the client_id matches the Client ID you assigned to Google, and that the redirect_uri matches the redirect URL provided by Google for your service. These checks are important to prevent granting access to unintended or misconfigured client apps. If you support multiple OAuth 2.0 flows, also confirm that the response_type is code.
  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 authorization code for Google to use to access your API. The authorization code can be any string value, but it must uniquely represent the user, the client the token is for, and the code's expiration time, and it must not be guessable. You typically issue authorization codes that expire after approximately 10 minutes.
  4. 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
      
  5. Redirect the user's browser to the URL specified by the redirect_uri parameter. Include the authorization code you just generated and the original, unmodified state value when you redirect by appending the code and state parameters. The following is an example of the resulting URL:
    https://oauth-redirect.googleusercontent.com/r/YOUR_PROJECT_ID?code=AUTHORIZATION_CODE&state=STATE_STRING

Handle token exchange requests

Your service's token exchange endpoint is responsible for two kinds of token exchanges:

  • Exchange authorization codes for access tokens and refresh tokens
  • Exchange refresh tokens for access tokens

Token exchange requests include the following parameters:

Token exchange endpoint parameters
client_id A string that identifies the request origin as Google. This string must be registered within your system as Google's unique identifier.
client_secret A secret string that you registered with Google for your service.
grant_type The type of token being exchanged. It's either authorization_code or refresh_token.
code When grant_type=authorization_code, this parameter is the code Google received from either your sign-in or token exchange endpoint.
redirect_uri When grant_type=authorization_code, this parameter is the URL used in the initial authorization request.
refresh_token When grant_type=refresh_token, this parameter is the refresh token Google received from your token exchange endpoint.
Exchange authorization codes for access tokens and refresh tokens

After the user signs in and your authorization endpoint returns a short-lived authorization code to Google, Google sends a request to your token exchange endpoint to exchange the authorization code for an access token and a refresh token.

For these requests, the value of grant_type is authorization_code, and the value of code is the value of the authorization code you previously granted to Google. The following is an example of a request to exchange an authorization code for an access token and a refresh token:

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

client_id=GOOGLE_CLIENT_ID&client_secret=GOOGLE_CLIENT_SECRET&grant_type=authorization_code&code=AUTHORIZATION_CODE&redirect_uri=REDIRECT_URI

To exchange authorization codes for an access token and a refresh token, your token exchange endpoint responds to POST requests by executing the following steps:

  1. Verify that the client_id identifies the request origin as an authorized origin, and that the client_secret matches the expected value.
  2. Verify that the authorization code is valid and not expired, and that the client ID specified in the request matches the client ID associated with the authorization code.
  3. Confirm that the URL specified by the redirect_uri parameter is identical to the value used in the initial authorization request.
  4. If you can't verify all of the above criteria, return an HTTP 400 Bad Request error with {"error": "invalid_grant"} as the body.
  5. Otherwise, use the user ID from the authorization code to generate a refresh token and an access token. These tokens can be any string value, but they must uniquely represent the user and the client the token is for, and they must not be guessable. For access tokens, also record the expiration time of the token, which is typically an hour after you issue the token. Refresh tokens don't expire.
  6. Return the following JSON object in the body of the HTTPS response:
    {
    "token_type": "Bearer",
    "access_token": "ACCESS_TOKEN",
    "refresh_token": "REFRESH_TOKEN",
    "expires_in": SECONDS_TO_EXPIRATION
    }
    

Google stores the access token and the refresh token for the user and records the expiration of the access token. When the access token expires, Google uses the refresh token to get a new access token from your token exchange endpoint.

Exchange refresh tokens for access tokens

When an access token expires, Google sends a request to your token exchange endpoint to exchange a refresh token for a new access token.

For these requests, the value of grant_type is refresh_token, and the value of refresh_token is the value of the refresh token you previously granted to Google. The following is an example of a request to exchange a refresh token for an access token:

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

client_id=GOOGLE_CLIENT_ID&client_secret=GOOGLE_CLIENT_SECRET&grant_type=refresh_token&refresh_token=REFRESH_TOKEN

To exchange a refresh token for an access token, your token exchange endpoint responds to POST requests by executing the following steps:

  1. Verify that the client_id identifies the request origin as Google, and that the client_secret matches the expected value.
  2. Verify that the refresh token is valid, and that the client ID specified in the request matches the client ID associated with the refresh token.
  3. If you can't verify all of the above criteria, return an HTTP 400 Bad Request error with {"error": "invalid_grant"} as the body.
  4. Otherwise, use the user ID from the refresh token to generate an access token. These tokens can be any string value, but they must uniquely represent the user and the client the token is for, and they must not be guessable. For access tokens, also record the expiration time of the token, typically an hour after you issue the token.
  5. Return the following JSON object in the body of the HTTPS response:
    {
    "token_type": "Bearer",
    "access_token": "ACCESS_TOKEN",
    "expires_in": SECONDS_TO_EXPIRATION
    }
Manejar solicitudes de información de usuario

El punto final userinfo es un recurso protegido OAuth 2.0 que las reclamaciones de retorno sobre el usuario vinculado. La implementación y el alojamiento del punto final de userinfo es opcional, excepto en los siguientes casos de uso:

Una vez que el token de acceso se ha recuperado correctamente de su punto final de token, Google envía una solicitud a su punto final de información de usuario para recuperar información de perfil básica sobre el usuario vinculado.

encabezados de solicitud de punto final de userinfo
Authorization header El token de acceso de tipo Bearer.

Por ejemplo, si su userinfo punto final está disponible en https://myservice.example.com/userinfo , una solicitud puede tener un aspecto como el siguiente:

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

Para que su punto final de userinfo maneje las solicitudes, siga los siguientes pasos:

  1. Extraiga el token de acceso del encabezado de autorización y devuelva la información para el usuario asociado con el token de acceso.
  2. Si el token de acceso no es válido, devuelve un error HTTP 401 no autorizado con el uso de la WWW-Authenticate encabezado de respuesta. A continuación se muestra un ejemplo de una respuesta de error userinfo:
    HTTP/1.1 401 Unauthorized
    WWW-Authenticate: error="invalid_token",
    error_description="The Access Token expired"
    
    Si un 401 no autorizado, o cualquier otra respuesta de error sin éxito se devuelve durante el proceso de vinculación, el error será no recuperable, el token recuperada será descartado y el usuario tendrá para iniciar el proceso de vinculación nuevamente.
  3. Si el token de acceso es válido, el retorno y la respuesta HTTP 200 con el siguiente objeto JSON en el cuerpo de la respuesta HTTPS:

    {
    "sub": "USER_UUID",
    "email": "EMAIL_ADDRESS",
    "given_name": "FIRST_NAME",
    "family_name": "LAST_NAME",
    "name": "FULL_NAME",
    "picture": "PROFILE_PICTURE",
    }
    
    Si su userinfo de punto final devuelve una respuesta de éxito HTTP 200, el recuperado token y reclamaciones se registran en contra de Google del usuario cuenta.

    respuesta del punto final de userinfo
    sub Una identificación única que identifica al usuario en su sistema.
    email Dirección de correo electrónico del usuario.
    given_name Opcional: Nombre del usuario.
    family_name Opcional: Apellido del usuario.
    name Opcional: Nombre completo del usuario.
    picture Opcional: Foto del perfil de usuario.

Validando su implementación

您可以通过使用验证实现的OAuth 2.0游乐场工具。

在工具中,执行以下步骤:

  1. 单击配置打开的OAuth 2.0配置窗口。
  2. OAuth流场中,选择客户端
  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. 步骤1部分,不要选择任何谷歌范围。相反,将此字段留空或键入对您的服务器有效的范围(如果不使用 OAuth 范围,则输入任意字符串)。当您完成后,单击授权的API。
  6. 步骤2步骤3段,完成OAuth 2.0流程和验证每个步骤按预期工作。

您可以通过验证您的实现谷歌帐户链接演示工具。

在工具中,执行以下步骤:

  1. 点击登录在与谷歌按钮。
  2. 选择您要关联的帐户。
  3. 输入服务标识。
  4. (可选)输入您将请求访问的一个或多个范围。
  5. 单击开始演示
  6. 出现提示时,确认您可以同意并拒绝链接请求。
  7. 确认您被重定向到您的平台。