Deferred Account Creation Design

[vderosa]

This is a proposal to integrate Deferred Account Creation within amp-subscriptions-google.

New Endpoints

• hasAssociatedAccountUrl: sends a CORS request with POST payload. The payload contains a single Object ({ entitlements: ...}), which contains a stringified version of the entitlement granted to SubscribeWithGoogle. This URL should return a { found: true|false } message indicating whether a corresponding account exists on the backend.
• accountCreationRedirectUrl: a URL the user will be redirected to after giving consent to deferred account creation. This URL should reimplement the deferred account creation flow in swg-js, but can skip the confirmation step.

Flow

1. Check if new endpoints exist on amp-subscription-google configuration.
2. If yes, call hasAssociatedAccountUrl with granted entitlement.
3. If hasAssociatedAccountUrl returns false, begin deferred account creation flow.
4. If user confirms account creation, redirect to accountCreationRedirectUrl.

The flow can then be continued on the publisher side.

Changes to broader AMP

This design works by implementing pingback on amp-subscription-google. Previously, pingback would only be triggered by AMP for local platform. To make this work, AMP needs to call pingback on all platforms.

Draft Pull Request

See: ampproject/amphtml#26649