Accessing non-Google resources programmatically

This article shows you how to programmatically access a resource protected by Identity-Aware Proxy (IAP) using external identities.

There are several situations where you might want to do this:

  • Your frontend application leverages Identity Platform directly. Your backend API server is built using App Engine, and protected by IAP using external identities.

  • Your application is designed for use in a non-traditional browser environment, such as on Android, iOS, or the command-line, where using a browser redirect to authenticate users is infeasible.

Accessing resources

To access a resource programmatically using a service account JWT, see Authenticating with a service account JWT.

To access a resource programmatically using an ID token, follow these steps:

  1. Retrieve the user's ID token.

    Node.js

    Ensure the user is signed in. The code below shows a simple example of signing in a user with an email and password:

    // If signing in using project-level email/password IdP. // auth.tenantId = null; // This is null by default. // For signing in to a specific tenant using email/password. auth.tenantId = 'myTenantId'; auth.signInWithEmailAndPassword(email, password)  .then((user) => {  // User signed in. ID token can now be retrieved.  })  .catch((error) => {  // Handler error.  });

    You can then retrieve an ID token on the user object:

    user.getIdToken()  .then((idToken) => {  // idToken is now available and can be sent to API server.  })  .catch((error) => {  // Handler error.  });

    REST

    Calling signInWithPassword returns an ID token in the response:

    curl 'https://identitytoolkit.googleapis.com/v1/accounts:signInWithPassword?key=API-KEY' \ -H 'Content-Type: application/json' \ --data-binary '{ "email":"EMAIL", "password":"PASSWORD", "returnSecureToken":true, "tenantId":"TENANT-ID" # Only used in multi-tenancy }'

  2. Include the ID token in the authorization header when calling an endpoint protected by IAP.

    curl -H "Authorization: Bearer GCIP-ID-TOKEN" "https://example.appspot.com/api"