add play store + app store webhooks with in_app_purchases - RevenueCat alternative!

[matthewwong525]

Android webhook

• Workflow:
  • Setup pubsub + webhook
  • When someone buys make sure to set applicationUserName in the in_app_purchases package
    • this'll set the backend I think. it'll set the obfuscatedExternalAccountId
  • When it is triggered it either makes call to:
    • https://developers.google.com/android-publisher/api-ref/rest/v3/purchases.subscriptionsv2/get
    • https://developers.google.com/android-publisher/api-ref/rest/v3/purchases.products/get
  • Also make sure that it is a real payload. Maybe the call to the api makes sure that it is good. so no need to do that!
• Resources
  • realtime ref: https://developer.android.com/google/play/billing/rtdn-reference
  • setup guide with pubsub: https://developer.android.com/google/play/billing/getting-ready#configure-rtdn
• will use product id from stripe

Apple Webhook

• See how I did it for Fleeting Notes!
• https://github.com/fleetingnotes/supabase-functions/blob/main/supabase/functions/app-store-webhooks/index.ts