內(nèi)購介紹

IAP 是一套商品交易系統(tǒng)，而非簡單的支付系統(tǒng)，每一個購買項目都需要在開發(fā)者后臺的Itunes Connect后臺為 App 創(chuàng)建一個對應(yīng)的商品，提交給蘋果審核通過后，購買項目才會生效。內(nèi)購商品有四種類型：

• 消耗型項目：只可使用一次的產(chǎn)品，使用之后即失效，必須再次購買，如：游戲幣、一次性虛擬道具等
• 非消耗型項目：只需購買一次，不會過期或隨著使用而減少的產(chǎn)品。如：電子書
• 自動續(xù)期訂閱：允許用戶在固定時間段內(nèi)購買動態(tài)內(nèi)容的產(chǎn)品。除非用戶選擇取消，否則此類訂閱會自動續(xù)期，如：Apple Music這類按月訂閱的商品（有些雞賊的開發(fā)者以此收割對IAP商品不熟悉的用戶，參考App Store“流氓”軟件)
• 非續(xù)期訂閱：允許用戶購買有時限性服務(wù)的產(chǎn)品，此 App 內(nèi)購買項目的內(nèi)容可以是靜態(tài)的。此類訂閱不會自動續(xù)期

物料準備：

• App Store connect后臺填寫銀行賬戶信息，簽署內(nèi)購協(xié)議
• 配置商品信息，包括產(chǎn)品ID，產(chǎn)品價格等
• 配置用于測試IAP支付功能的沙箱賬戶

Xcode capablities 打開IAP開關(guān)

圖片

IAP 支付流程：

1.客戶端向Appstore請求購買產(chǎn)品，Appstore驗證產(chǎn)品成功后，從客戶端的Apple賬戶中扣費。

2.Appstore向客戶端返回一段receipt-data（票據(jù)），里面記錄了本次交易的證書和簽名信息。

3.客戶端向我們可以信任的服務(wù)器（后臺）提供receipt-data

4.服務(wù)器對receipt-data進行一次base64編碼

5.把編碼后的receipt-data發(fā)往itunes.appstore進行驗證

6.itunes.appstore返回驗證結(jié)果給服務(wù)器

7.服務(wù)器對商品購買狀態(tài)以及商品類型，向客戶端發(fā)放相應(yīng)的道具與推送數(shù)據(jù)更新通知

支付結(jié)束后有兩種驗證方式：
IAP built-in Model(本地驗證)：此種方式跳過來3-7步，在第2步中拿到票據(jù)直接向itunes.appstore請求驗證票據(jù)，根據(jù)票據(jù)的結(jié)果來修改數(shù)據(jù)。有一些單機游戲因為不涉及后臺服務(wù)器會采取此種方式，但由此單來的不安全也很明顯，比如一些越獄的手機會很容易對此進行一些數(shù)據(jù)操作

IAP Server Model(服務(wù)器驗證)：如果把數(shù)據(jù)放在服務(wù)器做校驗（如實走完1-7的流程），就不用擔(dān)心客戶端出現(xiàn)偽造票據(jù)等問題。但如果得到票據(jù)說明蘋果已經(jīng)扣款成功，就在這時向服務(wù)器發(fā)送票據(jù)驗證的時候出現(xiàn)來異常，這個時候可能網(wǎng)絡(luò)突然斷了，未把票據(jù)發(fā)送的服務(wù)器驗證，導(dǎo)致明明已經(jīng)扣了款，卻沒有收到相應(yīng)的內(nèi)購產(chǎn)品，出現(xiàn)了漏單問題。

對漏單的情況處理：
1：得到票據(jù)，立即保存本地，并向服務(wù)器驗證

2：驗證成功，刪除本地保存數(shù)據(jù)。若未成功，再次驗證重試。

3：APP重啟時，如有本地票據(jù)則與服務(wù)器進行認證，若認證成功則刪除票據(jù)。

4：若以上流程還未能解決漏單問題，則可在APP增加類似找回按鈕，依據(jù)本地保存票據(jù)進行找回（流程三）。

注：服務(wù)器需建立表單記錄票據(jù)數(shù)據(jù)，避免多次增加內(nèi)購產(chǎn)品。

代碼實現(xiàn)：

1.向蘋果后臺發(fā)起商品數(shù)據(jù)請求

// 每次發(fā)起新的購買請求之前，先處理上次是否有未完成的交易
- (void)finishLastPurchasedTransaction {
    NSArray *transactions = [SKPaymentQueue defaultQueue].transactions;
    if (transactions.count > 0) {
        SKPaymentTransaction* transaction = [transactions firstObject];
        if (transaction.transactionState == SKPaymentTransactionStatePurchased) {
            [[SKPaymentQueue defaultQueue] finishTransaction:transaction];
        }
    }
}

//    檢查設(shè)備是否支持內(nèi)購
if ([SKPaymentQueue canMakePayments]) {
    self.orderId = orderId;
    self.productId = productId;
    self.completion = completion;
    NSArray *product = @[self.productId];
    NSSet *set = [NSSet setWithArray:product];
    //開始請求
    self.request = [[SKProductsRequest alloc] initWithProductIdentifiers:set];
    self.request.delegate = self;
    [self.request start];
}

2.在SKProductsRequestDelegate中處理請求到的商品數(shù)據(jù),發(fā)起購買并監(jiān)聽購買過程

// 請求失敗
- (void)request:(SKRequest *)request didFailWithError:(NSError *)error {
    if (self.completion) {
        self.completion(kInAppPurchaseStatusFailed, nil);
    }
}

// 請求成功
- (void)requestDidFinish:(SKRequest *)request {

}

- (void)productsRequest:(nonnull SKProductsRequest *)request didReceiveResponse:(nonnull SKProductsResponse *)response {
    NSArray *products = response.products;
    if([products count] == 0) {
        if (self.completion) {
            self.completion(kInAppPurchaseStatusIAPProductsError, nil);
        }
        return;
    }
    
    //在所有商品中，找到當(dāng)前請求的商品
    SKProduct *targetProduct = nil;
    for (SKProduct *product in products) {
        if([product.productIdentifier isEqualToString:self.productId]) {
            targetProduct = product;
            break;
        }
    }
    
    if (!targetProduct) {
        if (self.completion) {
            self.completion(kInAppPurchaseStatusProductIDError, nil);
        }
        return;
    }
    [self showStatus:@"發(fā)起購買請求..."];
    SKPayment *payment = [SKPayment paymentWithProduct:targetProduct];
    [[SKPaymentQueue defaultQueue] addPayment:payment];
}

3.實現(xiàn)SKPaymentTransactionObserver代理，監(jiān)聽商品購買狀態(tài)

- (void)paymentQueue:(nonnull SKPaymentQueue *)queue updatedTransactions:(nonnull NSArray<SKPaymentTransaction *> *)transactions {
    for(SKPaymentTransaction *transaction in queue.transactions){
        self.transaction = transaction;
        switch (transaction.transactionState) {
            case SKPaymentTransactionStatePurchasing:
                [self showStatus:@"正在交易..."];
                break;
            case SKPaymentTransactionStatePurchased:
                if (self.completion) {
                    self.completion(kInAppPurchaseStatusSuccess, transaction.transactionIdentifier);
                }
                break;
            case SKPaymentTransactionStateRestored:
                if (self.completion) {
                    self.completion(kInAppPurchaseStatusIAPProductsRestored, nil);
                }
                [self finishTransaction];
                break;
            case SKPaymentTransactionStateFailed:
                if (transaction.error.code == SKErrorPaymentCancelled) {
                    if (self.completion) {
                        self.completion(kInAppPurchaseStatusCancel, nil);
                    }
                } else {
                    if (self.completion) {
                        self.completion(kInAppPurchaseStatusFailed, nil);
                    }
                }
                [self finishTransaction];
                break;
            default:
                break;
        }
    }
}

- (void)finishTransaction {
    if (self.transaction) {
        [[SKPaymentQueue defaultQueue] finishTransaction:self.transaction];
        self.transaction = nil;
    } else {
        [self finishLastPurchasedTransaction];
    }
    dispatch_async(dispatch_get_main_queue(), ^{
        [WLInAppPurchaseDefine dismiss];
    });
}

4.漏單情況處理

// 購買成功后：SKPaymentTransactionStatePurchased 本地存儲訂單號和transactionIdentifier

- (void)cacheCurrentOrderId:(NSString *)orderId andTransactionId:(NSString *)transactionId {
    if (orderId <= 0 || transactionId.length <= 0) {
        return;
    }
    NSDictionary *cacheDict = [[NSUserDefaults standardUserDefaults] objectForKey:kWLInAppPurchaseOrderCacheKey];
    NSMutableDictionary *tempDict = [NSMutableDictionary dictionaryWithDictionary:cacheDict];
    [tempDict setObject:transactionId forKey:orderId];
    [[NSUserDefaults standardUserDefaults] setObject:tempDict.copy forKey:kWLInAppPurchaseOrderCacheKey];
    [[NSUserDefaults standardUserDefaults] synchronize];
}

// 每次APP啟動檢查本地是否有未校驗的訂單號
- (void)checkCacheOrder:(NSString *)transactionId {
    NSDictionary *cacheDict = [[NSUserDefaults standardUserDefaults] objectForKey:kWLInAppPurchaseOrderCacheKey];
    if (cacheDict.allKeys.count > 0) {
        __weak typeof(self) weakSelf = self;
        [cacheDict enumerateKeysAndObjectsUsingBlock:^(id  _Nonnull key, id  _Nonnull obj, BOOL * _Nonnull stop) {
            __strong typeof(self) strongSelf = weakSelf;
            if ([obj isEqualToString:transactionId]) {
                strongSelf.orderId = key;
                strongSelf.transactionId = transactionId;
                [strongSelf verifyTransactionId:obj];
                *stop = YES;
            }
        }];
    } else {
        [self.IAPRequest finishTransaction];
    }
}

// 漏單校驗
- (void)verifyTransactionId:(NSString *)transactionId {
    //  服務(wù)器校驗憑據(jù)
    NSData *receiptData = [NSData dataWithContentsOfURL:[[NSBundle mainBundle] appStoreReceiptURL]];
    NSString *receipt = [receiptData base64EncodedStringWithOptions:0];
    if ([self.delegate respondsToSelector:@selector(verifyReceiptWithOrderId:transactionId:receipt:completion:)]) {
        __weak typeof(self) weakSelf = self;
        [self.delegate verifyReceiptWithOrderId:self.orderId transactionId:transactionId receipt:receipt completion:^(NSError * _Nonnull error, id  _Nonnull data) {
            __strong typeof(self) strongSelf = weakSelf;
            if (!strongSelf) return;
            if (!error) {
//                NSLog(@"校驗未完成的訂單成功");
                [strongSelf removeCacheOrder:strongSelf.orderId];
            } else {
                [strongSelf showToast:error.localizedDescription];
                [self retryVerifyCurrentOrder];
            }
            [strongSelf.IAPRequest finishTransaction];
            strongSelf.isProcessing = NO;
        }];
    }
}

// 服務(wù)器校驗成功后刪除存儲數(shù)據(jù)
- (void)removeCacheOrder:(NSString *)orderId {
    if (orderId <= 0) {
        return;
    }
    NSDictionary *cacheDict = [[NSUserDefaults standardUserDefaults] objectForKey:kWLInAppPurchaseOrderCacheKey];
    NSMutableDictionary *tempDict = [NSMutableDictionary dictionaryWithDictionary:cacheDict];
    if ([tempDict.allKeys containsObject:orderId]) {
        [tempDict removeObjectForKey:orderId];
        [[NSUserDefaults standardUserDefaults] setObject:tempDict.copy forKey:kWLInAppPurchaseOrderCacheKey];
        [[NSUserDefaults standardUserDefaults] synchronize];
    }
}