这是我如何在应用内购买库RMStore中解决此问题的演练。我将说明如何验证交易，包括验证整个收据。
乍看上去
获取收据并验证交易。如果失败，请刷新收据，然后重试。这使得验证过程是异步的，因为刷新收据是异步的。
从RMStoreAppReceiptVerifier：
RMAppReceipt *receipt = [RMAppReceipt bundleReceipt];
const BOOL verified = [self verifyTransaction:transaction inReceipt:receipt success:successBlock failure:nil]; // failureBlock is nil intentionally. See below.
if (verified) return;
// Apple recommends to refresh the receipt if validation fails on iOS
[[RMStore defaultStore] refreshReceiptOnSuccess:^{
RMAppReceipt *receipt = [RMAppReceipt bundleReceipt];
[self verifyTransaction:transaction inReceipt:receipt success:successBlock failure:failureBlock];
} failure:^(NSError *error) {
[self failWithBlock:failureBlock error:error];
}];
获取收据数据
收据在里面[[NSBundle mainBundle] appStoreReceiptURL]，实际上是PCKS7容器。我很喜欢加密技术，所以我用OpenSSL打开了这个容器。其他人显然只是通过系统框架来做到这一点。
向您的项目添加OpenSSL并非易事。该RMStore维基应该有所帮助。
如果选择使用OpenSSL打开PKCS7容器，则代码可能如下所示。从RMAppReceipt：
+ (NSData*)dataFromPKCS7Path:(NSString*)path
{
const char *cpath = [[path stringByStandardizingPath] fileSystemRepresentation];
FILE *fp = fopen(cpath, "rb");
if (!fp) return nil;
PKCS7 *p7 = d2i_PKCS7_fp(fp, NULL);
fclose(fp);
if (!p7) return nil;
NSData *data;
NSURL *certificateURL = [[NSBundle mainBundle] URLForResource:@"AppleIncRootCertificate" withExtension:@"cer"];
NSData *certificateData = [NSData dataWithContentsOfURL:certificateURL];
if ([self verifyPKCS7:p7 withCertificateData:certificateData])
{
struct pkcs7_st *contents = p7->d.sign->contents;
if (PKCS7_type_is_data(contents))
{
ASN1_OCTET_STRING *octets = contents->d.data;
data = [NSData dataWithBytes:octets->data length:octets->length];
}
}
PKCS7_free(p7);
return data;
}
稍后我们将详细介绍验证。
获取收据字段
收据以ASN1格式表示。它包含一般信息，一些用于验证目的的字段（我们将在后面介绍）以及每种适用的应用内购买的特定信息。
同样，在读取ASN1时，OpenSSL可以提供帮助。在RMAppReceipt中，使用一些辅助方法：
NSMutableArray *purchases = [NSMutableArray array];
[RMAppReceipt enumerateASN1Attributes:asn1Data.bytes length:asn1Data.length usingBlock:^(NSData *data, int type) {
const uint8_t *s = data.bytes;
const NSUInteger length = data.length;
switch (type)
{
case RMAppReceiptASN1TypeBundleIdentifier:
_bundleIdentifierData = data;
_bundleIdentifier = RMASN1ReadUTF8String(&s, length);
break;
case RMAppReceiptASN1TypeAppVersion:
_appVersion = RMASN1ReadUTF8String(&s, length);
break;
case RMAppReceiptASN1TypeOpaqueValue:
_opaqueValue = data;
break;
case RMAppReceiptASN1TypeHash:
_hash = data;
break;
case RMAppReceiptASN1TypeInAppPurchaseReceipt:
{
RMAppReceiptIAP *purchase = [[RMAppReceiptIAP alloc] initWithASN1Data:data];
[purchases addObject:purchase];
break;
}
case RMAppReceiptASN1TypeOriginalAppVersion:
_originalAppVersion = RMASN1ReadUTF8String(&s, length);
break;
case RMAppReceiptASN1TypeExpirationDate:
{
NSString *string = RMASN1ReadIA5SString(&s, length);
_expirationDate = [RMAppReceipt formatRFC3339String:string];
break;
}
}
}];
_inAppPurchases = purchases;
获取应用内购买
每次应用内购买都在ASN1中。解析它与解析常规收据信息非常相似。
在RMAppReceipt中，使用相同的帮助器方法：
[RMAppReceipt enumerateASN1Attributes:asn1Data.bytes length:asn1Data.length usingBlock:^(NSData *data, int type) {
const uint8_t *p = data.bytes;
const NSUInteger length = data.length;
switch (type)
{
case RMAppReceiptASN1TypeQuantity:
_quantity = RMASN1ReadInteger(&p, length);
break;
case RMAppReceiptASN1TypeProductIdentifier:
_productIdentifier = RMASN1ReadUTF8String(&p, length);
break;
case RMAppReceiptASN1TypeTransactionIdentifier:
_transactionIdentifier = RMASN1ReadUTF8String(&p, length);
break;
case RMAppReceiptASN1TypePurchaseDate:
{
NSString *string = RMASN1ReadIA5SString(&p, length);
_purchaseDate = [RMAppReceipt formatRFC3339String:string];
break;
}
case RMAppReceiptASN1TypeOriginalTransactionIdentifier:
_originalTransactionIdentifier = RMASN1ReadUTF8String(&p, length);
break;
case RMAppReceiptASN1TypeOriginalPurchaseDate:
{
NSString *string = RMASN1ReadIA5SString(&p, length);
_originalPurchaseDate = [RMAppReceipt formatRFC3339String:string];
break;
}
case RMAppReceiptASN1TypeSubscriptionExpirationDate:
{
NSString *string = RMASN1ReadIA5SString(&p, length);
_subscriptionExpirationDate = [RMAppReceipt formatRFC3339String:string];
break;
}
case RMAppReceiptASN1TypeWebOrderLineItemID:
_webOrderLineItemID = RMASN1ReadInteger(&p, length);
break;
case RMAppReceiptASN1TypeCancellationDate:
{
NSString *string = RMASN1ReadIA5SString(&p, length);
_cancellationDate = [RMAppReceipt formatRFC3339String:string];
break;
}
}
}];
应该注意的是，某些应用程序内购买（例如消耗品和不可续订的订阅）在收据中只会出现一次。您应该在购买后立即验证这些内容（再次，RMStore会帮助您完成此操作）。
验证一目了然
现在，我们从收据及其所有应用内购买中获取所有字段。首先，我们验证收据本身，然后简单地检查收据中是否包含交易产品。
下面是我们一开始就调用的方法。从RMStoreAppReceiptVerificator：
- (BOOL)verifyTransaction:(SKPaymentTransaction*)transaction
inReceipt:(RMAppReceipt*)receipt
success:(void (^)())successBlock
failure:(void (^)(NSError *error))failureBlock
{
const BOOL receiptVerified = [self verifyAppReceipt:receipt];
if (!receiptVerified)
{
[self failWithBlock:failureBlock message:NSLocalizedString(@"The app receipt failed verification", @"")];
return NO;
}
SKPayment *payment = transaction.payment;
const BOOL transactionVerified = [receipt containsInAppPurchaseOfProductIdentifier:payment.productIdentifier];
if (!transactionVerified)
{
[self failWithBlock:failureBlock message:NSLocalizedString(@"The app receipt doest not contain the given product", @"")];
return NO;
}
if (successBlock)
{
successBlock();
}
return YES;
}
验证收据
验证收据本身可以归结为：
- 检查收据是否有效PKCS7和ASN1。我们已经隐式地做到了这一点。
- 验证收据是否由Apple签名。这是在解析收据之前完成的，下面将详细介绍。
- 检查收据中包含的捆绑包标识符是否与您的捆绑包标识符相对应。您应该对捆绑包标识符进行硬编码，因为修改应用捆绑包和使用其他收据似乎并不困难。
- 检查收据中包含的应用程序版本是否与您的应用程序版本标识符相对应。出于上述相同的原因，您应该对应用程序版本进行硬编码。
- 检查收据哈希以确保收据与当前设备相对应。
从RMStoreAppReceiptVerificator进行的5个高级代码步骤：
- (BOOL)verifyAppReceipt:(RMAppReceipt*)receipt
{
// Steps 1 & 2 were done while parsing the receipt
if (!receipt) return NO;
// Step 3
if (![receipt.bundleIdentifier isEqualToString:self.bundleIdentifier]) return NO;
// Step 4
if (![receipt.appVersion isEqualToString:self.bundleVersion]) return NO;
// Step 5
if (![receipt verifyReceiptHash]) return NO;
return YES;
}
让我们深入到步骤2和5。
验证收据签名
返回当我们提取数据时，我们浏览了收据签名验证。收据上带有Apple Inc.根证书，可以从Apple根证书颁发机构下载。以下代码将PKCS7容器和根证书作为数据，并检查它们是否匹配：
+ (BOOL)verifyPKCS7:(PKCS7*)container withCertificateData:(NSData*)certificateData
{ // Based on: https://developer.apple.com/library/content/releasenotes/General/ValidateAppStoreReceipt/Chapters/ValidateLocally.html#//apple_ref/doc/uid/TP40010573-CH1-SW17
static int verified = 1;
int result = 0;
OpenSSL_add_all_digests(); // Required for PKCS7_verify to work
X509_STORE *store = X509_STORE_new();
if (store)
{
const uint8_t *certificateBytes = (uint8_t *)(certificateData.bytes);
X509 *certificate = d2i_X509(NULL, &certificateBytes, (long)certificateData.length);
if (certificate)
{
X509_STORE_add_cert(store, certificate);
BIO *payload = BIO_new(BIO_s_mem());
result = PKCS7_verify(container, NULL, store, NULL, payload, 0);
BIO_free(payload);
X509_free(certificate);
}
}
X509_STORE_free(store);
EVP_cleanup(); // Balances OpenSSL_add_all_digests (), per http://www.openssl.org/docs/crypto/OpenSSL_add_all_algorithms.html
return result == verified;
}
在解析收据之前，这是从一开始就完成的。
验证收据哈希
收据中包含的哈希值是设备ID的SHA1，收据中包含的一些不透明值和捆绑包ID。
这是在iOS上验证收据哈希的方法。从RMAppReceipt：
- (BOOL)verifyReceiptHash
{
// TODO: Getting the uuid in Mac is different. See: https://developer.apple.com/library/content/releasenotes/General/ValidateAppStoreReceipt/Chapters/ValidateLocally.html#//apple_ref/doc/uid/TP40010573-CH1-SW5
NSUUID *uuid = [[UIDevice currentDevice] identifierForVendor];
unsigned char uuidBytes[16];
[uuid getUUIDBytes:uuidBytes];
// Order taken from: https://developer.apple.com/library/content/releasenotes/General/ValidateAppStoreReceipt/Chapters/ValidateLocally.html#//apple_ref/doc/uid/TP40010573-CH1-SW5
NSMutableData *data = [NSMutableData data];
[data appendBytes:uuidBytes length:sizeof(uuidBytes)];
[data appendData:self.opaqueValue];
[data appendData:self.bundleIdentifierData];
NSMutableData *expectedHash = [NSMutableData dataWithLength:SHA_DIGEST_LENGTH];
SHA1(data.bytes, data.length, expectedHash.mutableBytes);
return [expectedHash isEqualToData:self.hash];
}
这就是要点。我可能在这里或那里缺少任何东西，因此我可能稍后再回到这篇文章。无论如何，我建议浏览完整的代码以获取更多详细信息。