IAP的實(shí)現(xiàn)的流程

IAP流程

• app端通過產(chǎn)品Id發(fā)送創(chuàng)建SKProductsRequest請(qǐng)求獲取產(chǎn)品
• 獲取到產(chǎn)品后創(chuàng)建SKPayment發(fā)起支付請(qǐng)求
• 監(jiān)聽支付回調(diào)
• 支付成功獲取支付憑證
• 通過支付憑證，向服務(wù)端發(fā)起請(qǐng)求，校驗(yàn)憑證的正確性，創(chuàng)建訂單
• app端接收校驗(yàn)后的服務(wù)器響應(yīng)，接收數(shù)據(jù)回調(diào)

IAP自動(dòng)續(xù)期訂閱代碼實(shí)戰(zhàn)

• 以設(shè)計(jì)一個(gè)IAPService模塊舉例說明

IAPService的對(duì)外接口

• 直接購買
• 注意：怎么才叫購買成功：Apple端支付成功，自己的服務(wù)端校驗(yàn)成功，訂單生產(chǎn)成功，才算完成了購買，所以SKPaymentQueue.default().finishTransaction(lastTansation)要在這些流程都跑通之后，才去調(diào)用，如果不調(diào)這個(gè)finish方法，則可以從 SKPaymentQueue.default().transactions獲取到這相關(guān)的交易，喚醒操作校驗(yàn)未完成的訂單或者訂閱續(xù)費(fèi)成功之后，都可以在這個(gè)transactions中獲取到，但是有可能有延遲，所以要在每次app啟動(dòng)的時(shí)候，執(zhí)行一個(gè)喚醒操作

func buyProduct(_ productId: String) {
        if SKPaymentQueue.canMakePayments() {
            let prefetched = prefetchProducts[productId]
            let lastTansation = SKPaymentQueue.default().transactions.filter { $0.payment.productIdentifier == productId }.first
            if let lastTansation = lastTansation, lastTansation.transactionState == .purchased { /// 購買成功過，直接去校驗(yàn)
                let productId = lastTansation.payment.productIdentifier
                let isFirstBuy = lastTansation.original == nil
                verifyBuySession(productId, isFirstBuy: isFirstBuy) {
                    SKPaymentQueue.default().finishTransaction(lastTansation)
                }
            } else if let prefetched = prefetched {
                let payment = SKPayment(product: prefetched)
                SKPaymentQueue.default().add(payment)
            } else {
                var products = Set<String>()
                products.insert(productId)
                let request = SKProductsRequest(productIdentifiers: products)
                request.delegate = self
                request.start()
            }
        } else {
            buyFailure.call(nil)
            NotificationCenter.default.post(name: NSNotification.Name.iapBuyFailure, object: nil)
        }
    }

 func productsRequest(_ request: SKProductsRequest, didReceive response: SKProductsResponse) {
        if response.products.isEmpty {
            return
        }
        if request == preFetchRequest {
            /// 注意線程安全
            lock.lock()
            response.products.forEach { product in
                prefetchProducts[product.productIdentifier] = product
            }
            lock.unlock()
            return
        }
        
        if let product = response.products.first {
            let payment = SKPayment(product: product)
            SKPaymentQueue.default().add(payment)
        } else {
            buyFailure.call(nil)
            NotificationCenter.default.post(name: NSNotification.Name.iapBuyFailure, object: nil)
        }
    }

 func paymentQueue(_ queue: SKPaymentQueue, updatedTransactions transactions: [SKPaymentTransaction]) {
        transactions.forEach { (transation) in
            switch transation.transactionState {
            /// 購買成功
            case .purchased:
                let productId = transation.payment.productIdentifier
                let isFirstBuy = transation.original == nil
                verifyBuySession(productId, isFirstBuy: isFirstBuy) {
                    SKPaymentQueue.default().finishTransaction(transation)
                }
            case .failed:
                handleFailed(transation)
            case .restored:
                handleRestored(transation)
            case .purchasing:
                break
            case .deferred:
                break
            @unknown default:
                debugPrint("IAPService - @unknown default")
            }
        }
    }

• 冷啟動(dòng)校驗(yàn)（喚醒操作）
  • 如果有在蘋果服務(wù)器購買成功，但是在自己的服務(wù)器都沒有創(chuàng)建好訂單，則冷啟動(dòng)重新校驗(yàn)未完成的訂單
  • 如果沒有未完成的訂單，則獲取一下當(dāng)前憑證的最新信息，保持信息的同步，比如訂閱過期了，app端有可能沒有接收到回調(diào)信息，這樣就會(huì)導(dǎo)致APP端一直處于訂閱狀態(tài)，當(dāng)然注冊(cè)了交易狀態(tài)的監(jiān)聽也可以知道，但是信息有可能會(huì)延遲，這樣做，相當(dāng)于一個(gè)保險(xiǎn)操作
  • 喚醒操作的目的：1.初始化IAPService單例，注冊(cè)監(jiān)聽，2.校驗(yàn)續(xù)費(fèi)或者已經(jīng)在Apple購買成功，但是沒有在自己服務(wù)端生成訂單的交易

    /// 冷啟動(dòng)校驗(yàn)未完成的訂單
    func wakeUp() {
        guard SKPaymentQueue.canMakePayments() else {
            return
        }
        guard let lastTansition = SKPaymentQueue.default().transactions.filter({ $0.transactionState == .purchased}).first  else {
            return
        }
        let productId = lastTansition.payment.productIdentifier
        let isFirstBuy = lastTansition.original == nil
        verifyBuySession(productId, isFirstBuy: isFirstBuy) {
            SKPaymentQueue.default().finishTransaction(lastTansition)
        }
    }

• 恢復(fù)購買
  • 發(fā)起回復(fù)購買
  • paymentQueueRestoreCompletedTransactionsFinished中接收回調(diào)的結(jié)果
  • 如果憑證有效,直接調(diào)取服務(wù)端校驗(yàn)接口，返回IAP數(shù)據(jù)信息
  • 如果憑證無效, 發(fā)起刷新憑證請(qǐng)求, 監(jiān)聽請(qǐng)求回調(diào)結(jié)果
  • 再次嘗試判斷憑證是否為空，若不為空，則進(jìn)行憑證校驗(yàn)，返回IAP數(shù)據(jù)信息

 func restore() {
        guard SKPaymentQueue.canMakePayments() else {
            return
        }
        SKPaymentQueue.default().restoreCompletedTransactions()
    }

 func paymentQueueRestoreCompletedTransactionsFinished(_ queue: SKPaymentQueue) {
        /// 憑證無效則刷新一下
        if reciepString == nil {
            let refresh = SKReceiptRefreshRequest()
            refresh.delegate = self
            refresh.start()
        } else {
            verifyRestoreSession()
        }
    }
    
  func paymentQueue(_ queue: SKPaymentQueue, restoreCompletedTransactionsFailedWithError error: Error) {
        restoreFailure.call(error)
        NotificationCenter.default.post(name: NSNotification.Name.iapRestoreFailure, object: nil)
    }

 func requestDidFinish(_ request: SKRequest) {
        /// 如果是恢復(fù)購買時(shí)刷新憑證的request
        if request is SKReceiptRefreshRequest {
            if reciepString == nil {
                restoreFailure.call(AppError(message: "error.SKReceiptRefreshRequest", code: ErrorCode(rawValue: -100) ?? .none))
                NotificationCenter.default.post(name: NSNotification.Name.iapRestoreFailure, object: nil)
            } else {
                verifyRestoreSession()
            }
        }
        if request == preFetchRequest {
            preFetchRequest = nil
        }
    }

• 預(yù)先拉取商品

  func prefetchProducts(_ productIds: Set<String>) {
        guard SKPaymentQueue.canMakePayments() else { return }
        preFetchRequest = SKProductsRequest(productIdentifiers: productIds)
        preFetchRequest?.delegate = self
        preFetchRequest?.start()
    }

• 信息回調(diào)（通知的形式）

內(nèi)部接口

• 在IAPService模塊創(chuàng)建時(shí)添加支付狀態(tài)的監(jiān)聽

 private override init() {
        super.init()
        SKPaymentQueue.default().add(self)
    }

• 處理產(chǎn)品請(qǐng)求，交易狀態(tài)更新的回調(diào)

extension IAPService: SKProductsRequestDelegate {
    func productsRequest(_ request: SKProductsRequest, didReceive response: SKProductsResponse) {
        if response.products.isEmpty {
            return
        }
        if request == preFetchRequest {
            /// 注意線程安全
            lock.lock()
            response.products.forEach { product in
                prefetchProducts[product.productIdentifier] = product
            }
            lock.unlock()
            return
        }
        
        if let product = response.products.first {
            let payment = SKPayment(product: product)
            SKPaymentQueue.default().add(payment)
        } else {
            buyFailure.call(nil)
            NotificationCenter.default.post(name: NSNotification.Name.iapBuyFailure, object: nil)
        }
    }
    
    func request(_ request: SKRequest, didFailWithError error: Error) {
        buyFailure.call(error)
        NotificationCenter.default.post(name: NSNotification.Name.iapBuyFailure, object: nil)
    }
    
    func requestDidFinish(_ request: SKRequest) {
        /// 如果是恢復(fù)購買時(shí)刷新憑證的request
        if request is SKReceiptRefreshRequest {
            if reciepString == nil {
                restoreFailure.call(AppError(message: "error.SKReceiptRefreshRequest", code: ErrorCode(rawValue: -100) ?? .none))
                NotificationCenter.default.post(name: NSNotification.Name.iapRestoreFailure, object: nil)
            } else {
                verifyRestoreSession()
            }
        }
        if request == preFetchRequest {
            preFetchRequest = nil
        }
    }
}

extension IAPService: SKPaymentTransactionObserver {
    func paymentQueue(_ queue: SKPaymentQueue, updatedTransactions transactions: [SKPaymentTransaction]) {
        transactions.forEach { (transation) in
            switch transation.transactionState {
            /// 購買成功
            case .purchased:
                let productId = transation.payment.productIdentifier
                let isFirstBuy = transation.original == nil
                verifyBuySession(productId, isFirstBuy: isFirstBuy) {
                    SKPaymentQueue.default().finishTransaction(transation)
                }
            case .failed:
                handleFailed(transation)
            case .restored:
                handleRestored(transation)
            case .purchasing:
                break
            case .deferred:
                break
            @unknown default:
                debugPrint("IAPService - @unknown default")
            }
        }
    }
    
    func paymentQueueRestoreCompletedTransactionsFinished(_ queue: SKPaymentQueue) {
        /// 憑證無效則刷新一下
        if reciepString == nil {
            let refresh = SKReceiptRefreshRequest()
            refresh.delegate = self
            refresh.start()
        } else {
            verifyRestoreSession()
        }
    }
    
    func paymentQueue(_ queue: SKPaymentQueue, restoreCompletedTransactionsFailedWithError error: Error) {
        restoreFailure.call(error)
        NotificationCenter.default.post(name: NSNotification.Name.iapRestoreFailure, object: nil)
    }
}

• 校驗(yàn)憑證，生成訂單，獲取當(dāng)前憑證的最新信息

  /// 校驗(yàn)購買時(shí)使用
    fileprivate func verifyBuySession(_ productId: String? = nil, isFirstBuy: Bool, success: (() -> Void)? = nil) {
        let provider = MoyaProvider<IAPNetWorkTarget>()
        guard let reciepString = reciepString else {
            return
        }
        
        func paraseReponse(_ response: Result<Response, MoyaError>, success: (() -> Void)? = nil) {
            switch response {
            case .success(let res):
                guard let resModel = try? res.model(IAPResponse.self) else {
                    return
                }
                if let data = resModel.data {
                    self.buySuccess.call(data)
                    NotificationCenter.default.post(name: NSNotification.Name.iapBuySuccess, object: data)
                    success?()
                } else {
                    let error = AppError(message: resModel.message ?? "", code: ErrorCode(rawValue: resModel.status) ?? .none)
                    self.buyFailure.call(error)
                    NotificationCenter.default.post(name: NSNotification.Name.iapBuyFailure, object: nil)
                }
            case .failure(let error):
                self.buyFailure.call(AppError(message: error.localizedDescription, code: ErrorCode(rawValue: -100) ?? .none))
                NotificationCenter.default.post(name: NSNotification.Name.iapBuyFailure, object: nil)
            }
        }
        if isFirstBuy, let productId = productId { /// 訂閱
            provider.request(.purchase(productId, reciepString)) { response in
                paraseReponse(response, success: success)
            }
        } else { /// 續(xù)費(fèi)
            provider.request(.checkReceipt(reciepString)) { response in
                paraseReponse(response, success: success)
            }
        }
    }
    
    /// 校驗(yàn)恢復(fù)時(shí)使用
    fileprivate func verifyRestoreSession(_ success: (() -> Void)? = nil) {
        let provider = MoyaProvider<IAPNetWorkTarget>()
        guard let reciepString = reciepString else {
            return
        }
        provider.request(.checkReceipt(reciepString)) { response in
            switch response {
            case .success(let res):
                guard let resModel = try? res.model(IAPResponse.self) else {
                    return
                }
                if let data = resModel.data {
                    self.restoreSuccess.call(data)
                    NotificationCenter.default.post(name: NSNotification.Name.iapRestoreSuccess, object: data)
                    success?()
                } else {
                    let error = AppError(message: resModel.message ?? "", code: ErrorCode(rawValue: resModel.status) ?? .none)
                    self.restoreFailure.call(error)
                    NotificationCenter.default.post(name: NSNotification.Name.iapRestoreFailure, object: nil)
                }
            case .failure(let error):
                self.restoreFailure.call(AppError(message: error.localizedDescription, code: ErrorCode(rawValue: -100) ?? .none))
                NotificationCenter.default.post(name: NSNotification.Name.iapRestoreFailure, object: nil)
            }
        }
    }
    
    ///獲取當(dāng)前憑證的最新信息：比如訂閱過期，Apple知道訂閱過期了，但是app端有可能不知道，所以需要主動(dòng)獲取一次
    fileprivate func checkCurrentReciept() {
        let provider = MoyaProvider<IAPNetWorkTarget>()
        guard let reciepString = reciepString else {
            return
        }
        provider.request(.checkReceipt(reciepString)) { response in
            switch response {
            case .success(let res):
                guard let resModel = try? res.model(IAPResponse.self) else {
                    return
                }
                if let data = resModel.data {
                    NotificationCenter.default.post(name: NSNotification.Name.iapInfoUpdated, object: data)
                }
            case .failure:
                break
            }
        }
    }

如何防止憑證被偽造?(面試經(jīng)常問)

• app端采用的是將憑證發(fā)送給我們自己的服務(wù)器，通過自己的服務(wù)器再向蘋果驗(yàn)證，蘋果返回的信息會(huì)決定這個(gè)憑證是否有效，如果無效則自己的服務(wù)器則返回錯(cuò)誤給客戶端。即把驗(yàn)證憑證這個(gè)操作，交由我們自己的服務(wù)器，我們和自己的服務(wù)器交互

• 自己服務(wù)器的數(shù)據(jù)安全由Https（對(duì)稱加密和非對(duì)稱加密）和一些自己約定的通信方式來保證（對(duì)稱加密）

• 完整代碼傳送門