Vinculación de cuentas con OAuth

El tipo de vinculación de OAuth es compatible con dos flujos de OAuth 2.0 estándar de la industria: los flujos de código implícito y de autorización.

In the implicit code 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 the Assistant to your Action.

In the authorization code flow, you need two endpoints:

• The authorization endpoint, which is responsible for presenting the sign-in UI to your users that aren't already signed in and recording consent to the requested access in the form of a short-lived authorization code.
• 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.

Although the implicit code flow is simpler to implement, Google recommends that access tokens issued using the implicit flow never expire, because using token expiration with the implicit flow forces the user to link their account again. If you need token expiration for security reasons, you should strongly consider using the auth code flow instead.

Implementa la vinculación de cuentas mediante OAuth

Configura el proyecto

Si deseas configurar tu proyecto para que use la vinculación de OAuth, sigue estos pasos:

1. Abre la Consola de Actions y selecciona el proyecto que deseas usar.
2. Haz clic en la pestaña Desarrollo y elige Vinculación de cuentas.
3. Habilita el interruptor que se encuentra junto a Vinculación de cuentas.
4. En la sección Creación de cuenta, selecciona No, solo quiero permitir la creación de cuentas en mi sitio web.

5. En Tipo de vinculación, selecciona OAuth y Código de autorización.

   

6. En Información del cliente (Client information), haz lo siguiente:

   • Asigna un valor al ID de cliente emitido por tus acciones a Google para identificar las solicitudes que provienen de Google.
   • Toma nota del valor del ID de cliente emitido por Google para tus acciones.
   • Inserta las URL para tus extremos de autorización y de intercambio de tokens.

6. Haz clic en Guardar.

Implementa tu 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 the Action user to access your service.

When your Action 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.

OAuth 2.0 auth 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 would transfer 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 by redirecting 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 the Assistant to your fulfillment webhook contains an access token.

Handle authorization requests

When your Action needs to perform account linking via an OAuth 2.0 authorization code flow, Google sends the user to your authorization endpoint with a request that includes the following parameters:

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

GET https://myservice.example.com/auth?client_id=GOOGLE_CLIENT_ID&redirect_uri=REDIRECT_URI&state=STATE_STRING&scope=REQUESTED_SCOPES&response_type=code

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

1. Verify that the client_id matches the Google client ID you registered with 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 that Google will 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

   YOUR_PROJECT_ID is the ID found on the Project settings page of the Actions Console.

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:

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 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 the following:
   • The authorization code is valid and not expired, and the client ID specified in the request matches the client ID associated with the authorization code.
   • The URL specified by the redirect_uri parameter is identical to the value used in the initial authorization request.
3. If you cannot verify all of the above criteria, return an HTTP 400 Bad Request error with {"error": "invalid_grant"} as the body.
4. Otherwise, using the user ID from the authorization code, 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 (typically an hour after you issue the token). Refresh tokens do not expire.
5. 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 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 cannot 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
   }

Diseñar la interfaz de usuario de voz para el flujo de autenticación

Comprueba si el usuario está verificado y comienza el flujo de vinculación de cuentas

1. Abre tu proyecto de Actions Builder en la Consola de Actions.
2. Crea una escena nueva para comenzar a vincular cuentas en tu acción:
   1. Haz clic en Scenes.
   2. Haz clic en el ícono de agregar (+) para agregar una escena nueva.
3. En la escena recién creada, haz clic en el ícono de agregar add para Conditions.
4. Agrega una condición que verifique si el usuario asociado con la conversación es un usuario verificado. Si la verificación falla, tu Acción no podrá realizar la vinculación de cuentas durante la conversación y debería volver a proporcionar acceso a la funcionalidad que no requiera la vinculación de cuentas.
   1. En el campo Enter new expression, en Condición, ingresa la siguiente lógica: user.verificationStatus != "VERIFIED"
   2. En Transición, selecciona una escena que no requiera la vinculación de una cuenta o una que sea el punto de entrada a la funcionalidad solo para invitados.

1. Haz clic en el ícono de agregar add para Conditions.
2. Agrega una condición para activar un flujo de vinculación de cuentas si el usuario no tiene una identidad asociada.
   1. En el campo Enter new expression, en Condición, ingresa la siguiente lógica: user.verificationStatus == "VERIFIED"
   2. En Transition, selecciona la escena del sistema Account Linking.
   3. Haz clic en Guardar.

Después de guardar, se agrega a tu proyecto una nueva escena del sistema de vinculación de cuentas llamada <SceneName>_AccountLinking.

Personaliza la escena de vinculación de cuentas

1. En Scenes, selecciona la escena del sistema de vinculación de cuentas.
2. Haz clic en Send prompt y agrega una oración breve para describirle al usuario por qué la acción necesita acceder a su identidad (por ejemplo, "Para guardar tus preferencias").
3. Haz clic en Guardar.

1. En Condiciones, haz clic en Si el usuario completa la vinculación de cuentas correctamente.
2. Configura cómo debe proceder el flujo si el usuario acepta vincular su cuenta. Por ejemplo, llama al webhook para procesar cualquier lógica empresarial personalizada que se requiera y realizar la transición a la escena de origen.
3. Haz clic en Guardar.

1. En Condiciones, haz clic en Si el usuario cancela o descarta la vinculación de cuentas.
2. Configura cómo debe proceder el flujo si el usuario no acepta vincular su cuenta. Por ejemplo, envía un mensaje de confirmación y redirecciona a escenas que proporcionen funcionalidades que no requieren la vinculación de cuentas.
3. Haz clic en Guardar.

1. En Condiciones, haz clic en Si se produce un error de sistema o red.
2. Configura cómo debe proceder el flujo si el flujo de vinculación de cuentas no se puede completar debido a errores del sistema o de la red. Por ejemplo, envía un mensaje de confirmación y redirecciona a escenas que proporcionen funcionalidades que no requieren la vinculación de cuentas.
3. Haz clic en Guardar.

Controla las solicitudes de acceso a los datos

Si la solicitud de Asistente contiene un token de acceso, primero verifica que el token sea válido (y no haya vencido) y, luego, recupera la cuenta de usuario asociada de tu base de datos.