objective c - Notification of cancellation of auto-renewal for an in-app purchase

Question

I am working on an iPhone app and I want to implement the new model of auto-renewal for in-app purchases. I am able to successfully implement transactions and can even get subscribed to the app, but what if the user cancels the auto renewal subscription?

How will I be able to know that it has been cancelled, and so not continue to allow access (once expired)?

Answer 1

You can find the expiration date of a user's subscription by sending a receipt verification to Apple's servers. Check out figure 1-3 on the In-App Purchase Programming Guide.

Basically the steps are:

1. On the device, get a transaction receipt for an in-app-purchase. Either one you've saved during a transaction or by calling [SKPaymentQueue restoreCompletedTransactions].
2. Send that receipt to your server. (This is preferred over trying to do a receipt verification with Apple's servers directly from the app, since that would require you to store your shared secret on the device.)
3. Send the receipt to Apple's servers from your server, and in the response look for a key named expires_date (expressed in milli seconds since Jan 1, 1970 GMT).

I used this guide to help me on the server side: Verifying Apple App Store Receipts For In App Purchases With PHP and cURL.

There is no way to determine if the user has auto-renewal turned on or off. Apple doesn't give you access to this information. The only way is to wait until the expiration date passes without a renewal.