I'm looking to implement the new Auto Renewable subscriptions using In App purchase but I am unsure how or when to check if the user is currently subscribed. My understanding is that when the user initially subscribes the app can use the purchase date along with the subscription date to calculate how long their subscription would last. What happens after this date has passed? How do we check if the user has auto renewed or cancelled?
If I use restoreCompletedTransactions to get a transaction and receipt for each renewal the user will be prompted to enter their iTunes password. Does this mean that if they have bought a 7 day subscription they will have to enter their password every 7 days when the app checks if the subscription is still valid?
IF you want to check on it from a web server, you ping their API and it returns the status of the auto-renewable subscription and info about the last payment. link
If you are on the device then you probably have to call restoreCompletedTransactions which I guess asks for the password.
I don't see any other method. I suppose from the device you could verify the subscription by contacting the same web service used on the server side? I don't know how the pros and cons of that.