Restoring Purchased Products

Users restore transactions to maintain access to content they’ve already purchased. For example, when they upgrade to a new phone, they don’t lose all of the items they purchased on the old phone. Include some mechanism in your app to let the user restore their purchases, such as a Restore Purchases button. Restoring purchases prompts for the user’s App Store credentials, which interrupts the flow of your app: because of this, don’t automatically restore purchases, especially not every time your app is launched.

In most cases, all your app needs to do is refresh its receipt and deliver the products in its receipt. The refreshed receipt contains a record of the user’s purchases in this app, on this device or any other device. However, some apps need to take an alternate approach for one of the following reasons:

Refreshing the receipt asks the App Store for the latest copy of the receipt. Refreshing a receipt does not create any new transactions. Although you should avoid refreshing multiple times in a row, this action would have same result as refreshing it just once.

Restoring completed transactions creates a new transaction for every completed transaction the user made, essentially replaying history for your transaction queue observer. While transactions are being restored, your app maintains its own state to keep track of why it’s restoring completed transactions and how it needs to handle them. Restoring multiple times creates multiple restored transactions for each completed transaction.

Give the user an appropriate level of control over what content is redownloaded. For example, don’t download three years worth of daily newpapers or hundreds of megabytes worth of game levels all at once.

Refreshing the App Receipt

Create a receipt refresh request, set a delegate, and start the request. The request supports optional properties for obtaining receipts in various states during testing such as expired receipts—for details, see the values for the initWithReceiptProperties: method of SKReceiptRefreshRequest.

request = [[SKReceiptRefreshRequest alloc] init];
request.delegate = self;
[request start];

After the receipt is refreshed, examine it and deliver any products that were added.

Restoring Completed Transactions

Your app starts the process by calling the restoreCompletedTransactions method of SKPaymentQueue. This sends a request to the App Store to restore all of your app’s completed transactions. If your app sets a value for the applicationUsername property of its payment requests, as described in “Detecting Irregular Activity,” use the restoreCompletedTransactionsWithApplicationUsername: method to provide the same information when restoring transactions.

The App Store generates a new transaction for each transaction that was previously completed. The restored transaction has a reference to the original transaction: instances of SKPaymentTransaction have a originalTransaction property, and the entries in the receipt have an Original Transaction Identifier field.

Your transaction queue observer is called with a status of SKPaymentTransactionStateRestored for each restored transaction, as described in “Waiting for the App Store to Process Transactions.” The action you take at this point depends on the design of your app.