in-app purchase, multiple auto-renewing subscriptions having different durations
问题 A question regarding in-app purchase auto-renewing subscriptions: I'm unclear how to handle the case where a user purchases multiple subscriptions of differing durations. It seems that Apple will recognize if the user has already purchased a given SKU (based on product-id) and prevent re-purchasing (my app gets a failed-transaction event in this case), but if I offer the same content using different product-ids having different durations, then the user can potentially purchase twice or more.