[Feature]: Support Legacy App based Subscriptions for Migrated Customers for Platform GW

Please select the area the issue is related to

Area/Gateway (Routing, API deployment in gateway etc.)

Please select the aspect the issue is related to

Aspect/API (API backends, definitions, contracts, interfaces, OpenAPI)

Suggested Feature

Support Legacy App based Subscriptions for Migrated Customers for Platform GW

Currently API Platform supports only Sub-Token Based Subscriptions.

Hence, need to support Legacy subscription which is JWT auth token based subscription. Currently Subscription Validation policy has two ways of validation,

1. Sub-Token based validation(Already implemented - Default flow)
2. No Sub Token based validation(Flow implemented for Migrated scenario)- If no sub-token is provided and if the subscription validation is enabled for the API validate the subscription with a fallback logic where subscription is validated against request context app id(can be whaterever unique to app like client-id)

Need to implement JWT Auth Policy to identify which app this JWT token belongs to and set the app-id/client-id to the request context so then by the time Subscription validation happens app-id/client-id is present in the request context.

Currently GW and Platform-API Subscriptions REST API has the ability to create subscriptions by following two approaches,

1. API ID - Policy ID - Sub Token (This is default approach which is already implemented)
2. API ID - Policy - App ID (Legacy approach which is not fully supported)- When a Legacy subscription is migrated Bijira Cloud to API Platform need to fully implement this REST API and websocket flows.

Also, need to implement Migration ETL tool related changes to use these REST APIs to migrate the legacy subscriptions.

Related Issues

No response

Start by reviewing the gateway and Platform-API subscription REST APIs, the JWT authentication policy, and the migration ETL tool mentioned in the issue. Done means legacy app-based subscriptions work through the REST and WebSocket flows, with the ETL migration changes included.