Where should I store data that needs to persist for a given appleID?

Question

The answer to this question may be iCloud storage, but I am using this for a very light-weight piece of data and think it may be extreme to use iCloud for this one purpose. We have an in-app subscription app. Before we provided the app for free but would not deliver any content to it until the user subscribed to content through the in-app subscription.

Some reviews indicate people think that we are trying to trick them by saying free and then saying they have to subscribe. We want the app to be listed as the price of the subscription to avoid this misunderstanding but after the first year has elapsed offer them the in-app subscription to continue. We plan to store the initial launch date in persistent storage so that we can determine when to begin requiring a subscription receipt.

1) We wanted to use the keychain storage since this information will persist even if a user removes the app from his/her device and then re-installs. The problem is if the user gets a new device and does not restore it from an encrypted backup, then the initialized value will be lost.

2) If we use our servers to store this value for them, then there seems to be no way to tie it to that appleID; so that is ruled out as a possibility.

3) Back to iCloud, it just seems like a lot to add iCloud support just for this, and I believe the user still has to have iCloud enabled for this to work.

Does anyone know the solution to this data persistence problem? Help is appreciated!

Answer 1

Yes, nsubiquitouskeyvaluestore is the way to get it synched with new devices. Using this in conjunction with both keychain for storing on a device after app as been removed and nsuserdefaults for quick and easy unconstrained access is the way to go. Apple also has a way to read receipts for the actual app purchase now, but it only works for iOS 7. Solutions should conditionally rely on receipt data from nsbundle.mainbundle url if it is available.