I have an iOS app where I sell digital music. I also have a site and soon an Android app where I want users to have access to the content they purchased on their iOS device. Right now, I'm using non-consumable In-App purchases per Apple's recommendation. However, I see some problems in trying to sync the user's purchases with my user database.
What if apple user A_apple is logged in as user A_myapp on my server and purchases song X? Now, when A_myapp logs out, but is still logged in as A_apple, am I allowed to deny access to the content? And what if A_apple now logs in on a different device and tries to restore their songs, but they're not logged in as A_myapp? Can I disallow access (and possibly give a warning about them not being logged in with the right account)?
One possible option is using consumable purchases. I would love to do this as it would give me more flexibility with the In-App purchases, and it would completely resolve the above issue as I would just keep track of the purchases using my own system. The In-App purchases would just be virtual currency. I'm worried that my app will get rejected if I use this.
Hope to get some answers from people with experience and/or references.