MKStoreKit.m

#import "MKStoreManager.h"

@interface MKStoreManager (PrivateMethods)

- (void) requestProductData;
- (BOOL) canCurrentDeviceUseFeature: (NSString*) featureID;
- (BOOL) verifyReceipt:(NSData*) receiptData;
- (void) enableContentForThisSession: (NSString*) productIdentifier;

@end

@implementation MKStoreManager

@synthesize catalog = _catalog;
@synthesize purchasableObjects = _purchasableObjects;
@synthesize storeObserver = _storeObserver;

static NSString *ownServer = nil;

static __weak id<MKStoreKitDelegate> _delegate;
static MKStoreManager* _sharedStoreManager;


- (void)dealloc {

    [_purchasableObjects release];

    [_storeObserver release];

    [_sharedStoreManager release];

    [super dealloc];
}

#pragma mark Delegates

+ (id)delegate {

    return _delegate;
}

+ (void)setDelegate:(id)newDelegate {

    _delegate = newDelegate;
}

#pragma mark Singleton Methods

+ (MKStoreManager*)sharedManager {
    @synchronized(self) {
        if (_sharedStoreManager == nil) {
            NSLog(@"!");
            _sharedStoreManager = [[self alloc] init];
            _sharedStoreManager.purchasableObjects = [[[NSMutableArray alloc] init] autorelease];
            [_sharedStoreManager requestProductData];
            _sharedStoreManager.storeObserver = [[[MKStoreObserver alloc] init] autorelease];
            [[SKPaymentQueue defaultQueue] addTransactionObserver:_sharedStoreManager.storeObserver];
        }
    }
    return _sharedStoreManager;
}


+ (id)allocWithZone:(NSZone *)zone
{
    @synchronized(self) {

        if (_sharedStoreManager == nil) {

            _sharedStoreManager = [super allocWithZone:zone];

            return _sharedStoreManager;  // assignment and return on first allocation
        }
    }

    return nil; //on subsequent allocation attempts return nil
}


- (id)copyWithZone:(NSZone *)zone
{
    return self;
}

- (id)retain
{
    return self;
}

- (unsigned)retainCount
{
    return UINT_MAX;  //denotes an object that cannot be released
}


- (id)autorelease
{
    return self;
}

#pragma mark Internal MKStoreKit functions

- (void) restorePreviousTransactions
{
    [[SKPaymentQueue defaultQueue] restoreCompletedTransactions];
}

 - (void)connection:(NSURLConnection*)connection didReceiveData:(NSData*)data {
   [_catalog_data appendData:data];
 }

 - (void)connectionDidFinishLoading:(NSURLConnection *)connection {
   _catalog = (NSMutableDictionary*)CFPropertyListCreateFromXMLData(kCFAllocatorDefault, (CFDataRef)_catalog_data, kCFPropertyListMutableContainersAndLeaves, nil);
   [_catalog_data release];
   _catalog_data = nil;

#if TARGET_IPHONE_SIMULATOR
   if([_delegate respondsToSelector:@selector(productFetchComplete)])
     [_delegate productFetchComplete];
#else
   NSMutableSet* __ids = [NSMutableSet set];
   NSArray* __keys = [_catalog allKeys];

   for (int i = 0; i < __keys.count; i++)
     [__ids addObject:[[_catalog objectForKey:[__keys objectAtIndex:i]] objectForKey:@"ID"]];

   SKProductsRequest *request= [[SKProductsRequest alloc] initWithProductIdentifiers:__ids];
   request.delegate = self;
   [request start];
#endif
 }

-(void) requestProductData {
  if (!_catalog_data) _catalog_data = [[NSMutableData alloc] init];

    NSURL *__url = [NSURL URLWithString:catalogURL];
   [NSURLConnection connectionWithRequest:[NSURLRequest requestWithURL:__url] delegate:self];

  _catalog = [[NSMutableDictionary alloc] initWithContentsOfURL:[NSURL URLWithString:catalogURL]];

  NSMutableSet* __ids = [NSMutableSet set];
  NSArray* __keys = [_catalog allKeys];

  for (int i = 0; i < __keys.count; i++) {
    //NSString* _id = [NSString stringWithFormat:@"%@%@", baseProductId, [[_products objectAtIndex:i] objectForKey:@"ID"]];
    //NSLog(@"%@\n", [[_catalog objectForKey:[__keys objectAtIndex:i]] objectForKey:@"ID"]);
    [__ids addObject:[[_catalog objectForKey:[__keys objectAtIndex:i]] objectForKey:@"ID"]];
  }

    SKProductsRequest *request= [[SKProductsRequest alloc] initWithProductIdentifiers:__ids];
    request.delegate = self;
    [request start];
}

- (void)productsRequest:(SKProductsRequest *)request didReceiveResponse:(SKProductsResponse *)response
{
    [self.purchasableObjects addObjectsFromArray:response.products];

#ifndef NDEBUG
    for(int i=0;i<[self.purchasableObjects count];i++)
    {
        SKProduct *product = [self.purchasableObjects objectAtIndex:i];
        NSLog(@"Feature: %@, Cost: %f, ID: %@",[product localizedTitle],
              [[product price] doubleValue], [product productIdentifier]);
    }

    for(NSString *invalidProduct in response.invalidProductIdentifiers)
        NSLog(@"Problem in iTunes connect configuration for product: %@", invalidProduct);
#endif

    [request autorelease];

    isProductsAvailable = YES;

    if([_delegate respondsToSelector:@selector(productFetchComplete)])
        [_delegate productFetchComplete];
}


// call this function to check if the user has already purchased your feature
+ (BOOL) isFeaturePurchased:(NSString*) featureId
{
    return [[NSUserDefaults standardUserDefaults] boolForKey:featureId];
}

- (SKProduct*) getSKProductByID:(NSString*) featureId {
  for(int i=0; i < [self.purchasableObjects count]; i++) {
        SKProduct *product = [self.purchasableObjects objectAtIndex:i];
    if ([[product productIdentifier] isEqualToString:featureId]) return product;
    }
  return nil;
}

// Call this function to populate your UI
// this function automatically formats the currency based on the user's locale

- (NSMutableArray*) purchasableObjectsDescription
{
    NSMutableArray *productDescriptions = [[NSMutableArray alloc] initWithCapacity:[self.purchasableObjects count]];
    for(int i=0;i<[self.purchasableObjects count];i++)
    {
        SKProduct *product = [self.purchasableObjects objectAtIndex:i];

        NSNumberFormatter *numberFormatter = [[NSNumberFormatter alloc] init];
        [numberFormatter setFormatterBehavior:NSNumberFormatterBehavior10_4];
        [numberFormatter setNumberStyle:NSNumberFormatterCurrencyStyle];
        [numberFormatter setLocale:product.priceLocale];
        NSString *formattedString = [numberFormatter stringFromNumber:product.price];
        [numberFormatter release];

        // you might probably need to change this line to suit your UI needs
        NSString *description = [NSString stringWithFormat:@"%@ (%@)",[product localizedTitle], formattedString];

#ifndef NDEBUG
        NSLog(@"Product %d - %@", i, description);
#endif
        [productDescriptions addObject: description];
    }

    [productDescriptions autorelease];
    return productDescriptions;
}

- (void) buyFeature:(NSString*) featureId
{
    if([self canCurrentDeviceUseFeature: featureId])
    {
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:NSLocalizedString(@"Review request approved", @"")
                                                        message:NSLocalizedString(@"You can use this feature for reviewing the app.", @"")
                                                       delegate:self
                                              cancelButtonTitle:NSLocalizedString(@"Dismiss", @"")
                                              otherButtonTitles:nil];
        [alert show];
        [alert release];

        [self enableContentForThisSession:featureId];
        return;
    }

    if ([SKPaymentQueue canMakePayments])
    {
        SKPayment *payment = [SKPayment paymentWithProductIdentifier:featureId];
        [[SKPaymentQueue defaultQueue] addPayment:payment];
    }
    else
    {
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:NSLocalizedString(@"In-App Purchasing disabled", @"")
                                                        message:NSLocalizedString(@"Check your parental control settings and try again later", @"")
                                                       delegate:self
                                              cancelButtonTitle:NSLocalizedString(@"Dismiss", @"")
                                              otherButtonTitles: nil];
        [alert show];
        [alert release];
    }
}

- (BOOL) canConsumeProduct:(NSString*) productIdentifier
{
    int count = [[NSUserDefaults standardUserDefaults] integerForKey:productIdentifier];

    return (count > 0);

}

- (BOOL) canConsumeProduct:(NSString*) productIdentifier quantity:(int) quantity
{
    int count = [[NSUserDefaults standardUserDefaults] integerForKey:productIdentifier];
    return (count >= quantity);
}

- (BOOL) consumeProduct:(NSString*) productIdentifier quantity:(int) quantity
{
    int count = [[NSUserDefaults standardUserDefaults] integerForKey:productIdentifier];
    if(count < quantity)
    {
        return NO;
    }
    else
    {
        count -= quantity;
        [[NSUserDefaults standardUserDefaults] setInteger:count forKey:productIdentifier];
        return YES;
    }

}

-(void) enableContentForThisSession: (NSString*) productIdentifier
{
    if([_delegate respondsToSelector:@selector(productPurchased:)])
        [_delegate productPurchased:productIdentifier];
}


#pragma mark In-App purchases callbacks
// In most cases you don't have to touch these methods
-(void) provideContent: (NSString*) productIdentifier
           forReceipt:(NSData*) receiptData
{
    if(ownServer != nil && SERVER_PRODUCT_MODEL)
    {
        // ping server and get response before serializing the product
        // this is a blocking call to post receipt data to your server
        // it should normally take a couple of seconds on a good 3G connection
        if(![self verifyReceipt:receiptData]) return;
    }

    NSRange range = [productIdentifier rangeOfString:baseProductId];
    NSString *countText = [productIdentifier substringFromIndex:range.location+[baseProductId length]];

    int quantityPurchased = [countText intValue];
    if(quantityPurchased != 0)
    {

        int oldCount = [[NSUserDefaults standardUserDefaults] integerForKey:productIdentifier];
        oldCount += quantityPurchased;

        [[NSUserDefaults standardUserDefaults] setInteger:oldCount forKey:productIdentifier];
    }
    else
    {
        [[NSUserDefaults standardUserDefaults] setBool:YES forKey:productIdentifier];
    }

    [[NSUserDefaults standardUserDefaults] synchronize];

    if([_delegate respondsToSelector:@selector(productPurchased:)])
        [_delegate productPurchased:productIdentifier];
}

- (void) transactionCanceled: (SKPaymentTransaction *)transaction
{

#ifndef NDEBUG
    NSLog(@"User cancelled transaction: %@", [transaction description]);
#endif

    if([_delegate respondsToSelector:@selector(transactionCanceled)])
        [_delegate transactionCanceled];
}

- (void) failedTransaction: (SKPaymentTransaction *)transaction
{
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:[transaction.error localizedFailureReason]
                                                    message:[transaction.error localizedRecoverySuggestion]
                                                   delegate:self
                                          cancelButtonTitle:NSLocalizedString(@"Dismiss", @"")
                                          otherButtonTitles: nil];
    [alert show];
    [alert release];
}



#pragma mark In-App purchases promo codes support
// This function is only used if you want to enable in-app purchases for free for reviewers
// Read my blog post http://mk.sg/31
- (BOOL) canCurrentDeviceUseFeature: (NSString*) featureID
{
    NSString *uniqueID = [[[UIDevice currentDevice] identifierForVendor]UUIDString];
    // check udid and featureid with developer's server

    if(ownServer == nil) return NO; // sanity check

    NSURL *url = [NSURL URLWithString:[NSString stringWithFormat:@"%@/%@", ownServer, @"featureCheck.php"]];

    NSMutableURLRequest *theRequest = [NSMutableURLRequest requestWithURL:url
                                                              cachePolicy:NSURLRequestReloadIgnoringCacheData
                                                          timeoutInterval:60];

    [theRequest setHTTPMethod:@"POST"];
    [theRequest setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];

    NSString *postData = [NSString stringWithFormat:@"productid=%@&udid=%@", featureID, uniqueID];

    NSString *length = [NSString stringWithFormat:@"%d", [postData length]];
    [theRequest setValue:length forHTTPHeaderField:@"Content-Length"];

    [theRequest setHTTPBody:[postData dataUsingEncoding:NSASCIIStringEncoding]];

    NSHTTPURLResponse* urlResponse = nil;
    NSError *error = [[[NSError alloc] init] autorelease];

    NSData *responseData = [NSURLConnection sendSynchronousRequest:theRequest
                                                 returningResponse:&urlResponse
                                                             error:&error];

    NSString *responseString = [[NSString alloc] initWithData:responseData encoding:NSASCIIStringEncoding];

    BOOL retVal = NO;
    if([responseString isEqualToString:@"YES"])
    {
        retVal = YES;
    }

    [responseString release];
    return retVal;
}

// This function is only used if you want to enable in-app purchases for free for reviewers
// Read my blog post http://mk.sg/

-(BOOL) verifyReceipt:(NSData*) receiptData
{
    if(ownServer == nil) return NO; // sanity check

    NSURL *url = [NSURL URLWithString:[NSString stringWithFormat:@"%@/%@", ownServer, @"verifyProduct.php"]];

    NSMutableURLRequest *theRequest = [NSMutableURLRequest requestWithURL:url
                                                              cachePolicy:NSURLRequestReloadIgnoringCacheData
                                                          timeoutInterval:60];

    [theRequest setHTTPMethod:@"POST"];
    [theRequest setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];

    NSString *receiptDataString = [[NSString alloc] initWithData:receiptData encoding:NSASCIIStringEncoding];
    NSString *postData = [NSString stringWithFormat:@"receiptdata=%@", receiptDataString];
    [receiptDataString release];

    NSString *length = [NSString stringWithFormat:@"%d", [postData length]];
    [theRequest setValue:length forHTTPHeaderField:@"Content-Length"];

    [theRequest setHTTPBody:[postData dataUsingEncoding:NSASCIIStringEncoding]];

    NSHTTPURLResponse* urlResponse = nil;
    NSError *error = [[[NSError alloc] init] autorelease];

    NSData *responseData = [NSURLConnection sendSynchronousRequest:theRequest
                                                 returningResponse:&urlResponse
                                                             error:&error];

    NSString *responseString = [[NSString alloc] initWithData:responseData encoding:NSASCIIStringEncoding];

    BOOL retVal = NO;
    if([responseString isEqualToString:@"YES"])
    {
        retVal = YES;
    }

    [responseString release];
    return retVal;
}
@end