How to handle not finished iOS in-app purchase of consumable?

I check & process IAP receipts (of consumables) on server side, and only call [[SKPaymentQueue defaultQueue] finishTransaction:transaction] on the app when it gets an okay back.

When the server does not return this okay (for whatever reason), the app correctly won't finish the transaction.

My question now is: Is there anything the app needs to do to receive the receipt again for a retry, or does iOS take care of this by invoking - (void)paymentQueue:(SKPaymentQueue*)queue updatedTransactions:(NSArray*)transactions`? When I reran my app, the item was re-submitted; but a user should not need to restart the app.

Related question: When I tried to buy a still pending item again (on the sandbox), I got an iOS alert saying that I bought it earlier but was not downloaded. Why is this? I would expect (and have actually seen) this for non-consumables. I could buy another consumable, with this previous one still pending.

Solution

Once you finish the transaction of CONSUMABLE IN-APP the following method will fire there add this statement "[[SKPaymentQueue defaultQueue] finishTransaction:transaction]" to remove the purchased product.Using this statement you can avoid the alert message(I bought it earlier but was not downloaded).

-(void)paymentQueue:(SKPaymentQueue *)queue updatedTransactions:(NSArray *)transactions
{
 for (SKPaymentTransaction *transaction in transactions)
 {        
    switch (transaction.transactionState) {
        case SKPaymentTransactionStatePurchased:
            if (transaction.downloads)
            {
                [[SKPaymentQueue defaultQueue]
                 startDownloads:transaction.downloads];
            } else {
                //Add the following line to remove purchased observer
                [[SKPaymentQueue defaultQueue] finishTransaction:transaction];                    
            }
            break;

        case SKPaymentTransactionStateFailed:
            [[SKPaymentQueue defaultQueue]
             finishTransaction:transaction];

            break;

    }
}
}