将 IAP 存储在 UserDefaults 中，这样用户就不需要在每次按下 "purchasable" 按钮时都恢复购买

Question

背景：我的应用程序提供了来自一组数组的大量提示。 'packs' 确定可以打开哪些提示。您从默认包开始，然后可以购买三个额外的包（packA、packB 和 packC）作为非消耗性 IAP。

我的目标是让用户支付一次，然后就可以在 he/she 喜欢的任何时候访问包；然而，一旦沙盒用户创建了 IAP，弹出窗口会显示 "You've already purchased this. Would you like to get it again for free?"。我显然不希望每次用户选择一个包时弹出这个。有没有办法让购买永久使用而不需要经常恢复购买？

以下是我当前的代码（匿名并简化为仅包含基本组件）：

import UIKit
import QuartzCore
import StoreKit

class ViewController: UIViewController, SKPaymentTransactionObserver {


    //MAIN SETUP SECTION XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

    let productID = "com.domain.appName.additionalPackages" 
    let defaults = UserDefaults.standard

    //I'm just putting "Various" here as a placeholder for my multiple buttons
    @IBOutlet weak var (Various): UIButton!

    override func viewDidLoad() {
        super.viewDidLoad()


        SKPaymentQueue.default().add(self) 

        //I don’t know if this actually does anything        
        func cleanUp() {
            for transaction in SKPaymentQueue.default().transactions {
                SKPaymentQueue.default().finishTransaction(transaction)
            }
        }

    }




    //PACK SELECTION SECTION XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

    var packA = 2
    var packB = 2
    var packC = 2
    var packsUnlocked = false

    @IBAction func selectPackA(_ sender: UIButton) {
        if packsUnlocked == false {
            print("It's locked, ‘Pack A’ not enabled")
        } else if packCounterA % 2 == 0 {
            if SKPaymentQueue.canMakePayments() { // In App Purchase
            let paymentRequest = SKMutablePayment()
            paymentRequest.productIdentifier = productID
            SKPaymentQueue.default().add(paymentRequest)
            print("Initiating Transaction")
        } else {
            print("No Purchased")
        }
        promptProvider.includeA.toggle()
            packCounterA += 1
        } else {
            promptProvider.includeA.toggle()
            packCounterA += 1
        }
    }

    @IBAction func selectPackB(_ sender: UIButton) {
        if packsUnlocked == false {
            print("It's locked, ‘Pack B’ not enabled")
        } else if packCounterB % 2 == 0 {
            if SKPaymentQueue.canMakePayments() { // In App Purchase
            let paymentRequest = SKMutablePayment()
            paymentRequest.productIdentifier = productID
            SKPaymentQueue.default().add(paymentRequest)
            print("Initiating Transaction")
        } else {
            print("No Purchased")
        }
            promptProvider.includeB.toggle()
            packCounterB += 1
        } else {
            promptProvider.includeB.toggle()
            packCounterB += 1
        }
    }

    @IBAction func selectPackC(_ sender: UIButton) {
        if packsUnlocked == false {
            print("It's locked, ‘Pack C' not enabled")
        } else if packCounterC % 2 == 0 {
            if SKPaymentQueue.canMakePayments() { // In App Purchase
            let paymentRequest = SKMutablePayment()
            paymentRequest.productIdentifier = productID
            SKPaymentQueue.default().add(paymentRequest)
            print("Initiating Transaction")
        } else {
            print("No Purchased")
        }
            promptProvider.includeC.toggle()
            packCounterC += 1
        } else {
            promptProvider.includeC.toggle()
            packCounterC += 1
        }
    }




    //TRANSACTION FINALIZATION SECTION XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

    func paymentQueue(_ queue: SKPaymentQueue, updatedTransactions transactions: [SKPaymentTransaction]) { 
        for transaction in transactions {
            guard
                transaction.transactionState != .purchasing,
                transaction.transactionState != .deferred
            else {
                //Optionally provide user feedback for pending or processing transactions
                continue
            }

            if transaction.transactionState == .purchased || transaction.transactionState == .restored {
                print("Transaction Successful")
                packsUnlocked = true
                //new
                defaults.set(true, forKey: "Purchase Pack") 
                UserDefaults.standard.synchronize() 
            } else if transaction.transactionState == .failed {
                print("Transaction Failed with error")
            }

            //Transaction can now be safely finished
            queue.finishTransaction(transaction)
        }
    }



}

这是我的第一个应用程序，但我认为问题在于将购买保存到 UserDefaults。我对此很陌生，所以非常感谢任何帮助。

谢谢

Answer 1

基础知识

购买完成后，您可以在 Bundle.main.appStoreReceiptURL 处查看收据。您可以使用该收据并根据 App Store 对其进行验证，以防止有人使用假收据。

验证响应会告诉您收据是合法的并且没有被退款。它还会告诉您订阅仍然有效以及何时到期。

您可以在客户端执行所有这些操作，但最佳做法是将收据存储在服务器上，这样您就可以在您的终端对其进行验证，而不是将其留给客户端进行潜在的操作。

Do not call the App Store server verifyReceipt endpoint from your app. You can't build a trusted connection between a user’s device and the App Store directly, because you don’t control either end of that connection, which makes it susceptible to a man-in-the-middle attack.

您可以在 docs. In addition you can set up hooks 中找到包括代码示例在内的更多信息，以便在订阅状态更改时主动通知您的服务器。

PoC

如果您不关心上述安全隐患而只想做一个概念验证，您可以在应用程序中执行此操作并检查用户是否已经购买：

从Bundle.main.appStoreReceiptURL?.path
按照所述 here 使用 App Store 服务器验证收据；请注意，沙盒和生产应用商店有不同的验证 URL
从验证响应中获取 product_id 和 expires_date 以了解已购买的产品以及是否已过期

请记住，如果用户卸载并重新安装应用程序，收据不会存储在设备上。然后用户必须恢复购买，应用程序从 App Store 服务器下载收据。这就是当您按下您可能在其他应用程序中熟悉的 "Restore Purchase" 按钮时发生的情况。恢复只需使用 SKReceiptRefreshRequest.

将 IAP 存储在 UserDefaults 中，这样用户就不需要在每次按下 "purchasable" 按钮时都恢复购买

Storing IAP in UserDefaults so the user doesn't need to restore the purchase every time a "purchasable" button is pressed

ios

swift

xcode

app-store-connect

基础知识

PoC