Example integration of FBStackableURLCache

QuickStart-FBStackableURLCache.m

// Note: Not pictured here: logic specific to the system that nukes the UICache.db  if we know the content is probably out of date

  /**
   * Make our base URL cache to the similar details as the standard default sharedURLCache in case someone is using it.
	 * From Apple Docs for NSURLCache:
	 * <li>Memory capacity: 4 megabytes (4 * 1024 * 1024 bytes)
	 * <li>Disk capacity: 20 megabytes (20 * 1024 * 1024 bytes)
	 * <li>Disk path: <nobr>(user home directory)/Library/Caches/(current application name)</nobr>
	 * <br>where:
	 * <br>user home directory is determined by calling
	 * <tt>NSHomeDirectory()</tt>
	 * <br>current application name is determined by calling
	 * <tt>[[NSProcessInfo processInfo] processName]</tt>
	 * </ul>
	 */
	
	FBStackableURLCache * baseCache = [[FBStackableURLCache alloc] initWithMemoryCapacity: (2 * 1024 * 1024)
																			 diskCapacity: (10 * 1024 * 1024)
																				 diskPath: @"Cache.db"];
	[FBStackableURLCache setSharedURLCacheStack:baseCache];

	WebviewAssetCache = [[NSURLCache alloc] initWithMemoryCapacity: (2 * 1024 * 1024)
															diskCapacity: (20 * 1024 * 1024)
																diskPath: @"UICache.db"];
	
	ImageAssetCache = [[NSURLCache alloc] initWithMemoryCapacity: (2 * 1024 * 1024) //No Point in making this bigger because NSURLCache won't keep files in memory if they're over 50kb
														  diskCapacity: (30 * 1024 * 1024)
															  diskPath: @"ImageCache.db"];



	// Webview UI Cache
	[baseCache registerCacheInclusionFilter:^BOOL(NSURLRequest *request) {
		return [request.URL.host hasPrefix: [MBWebUIViewController webviewHost]];
	} lookup:^NSCachedURLResponse *(NSURLRequest *request) {
		return [WebviewAssetCache cachedResponseForRequest:request];
	} storage:^(NSCachedURLResponse *response, NSURLRequest *request) {
		[WebviewAssetCache storeCachedResponse:response forRequest:request];
	}];


	// Facebook Image Cache (caches the redirect to the fb image, while modifying what really gets stored)
	NSRegularExpression *facebookRegex = [NSRegularExpression regularExpressionWithPattern:@"(graph.facebook.com/*/picture)+"
																				   options:0
																					 error:&error];
	[baseCache registerCacheInclusionFilter:^BOOL(NSURLRequest *request) {
		NSString *tmp;
		NSRange fbRange = [facebookRegex rangeOfFirstMatchInString:(tmp = request.URL.absoluteString) options:0 range:NSMakeRange(0, tmp.length)];
		return fbRange.location != NSNotFound;
	} lookup:^NSCachedURLResponse *(NSURLRequest *request) {
		NSCachedURLResponse * cachedResponse = [ImageAssetCache cachedResponseForRequest:request];
		NSDate * dateSaved = cachedResponse.userInfo[kFBSURLCacheDateSavedKey];
		
		if (![dateSaved isToday]) {
			dispatch_async(CONCURRENT_QUEUE, ^{
				NSURL * newURL = request.URL;
				if ([newURL.absoluteString hasSuffix:@"/picture"]) {
					// Lets falsify the facebook base URL, and instead fetch a 500x500 image :D
					newURL = [NSURL URLWithString:[NSString stringWithFormat:@"%@?width=500&height=500",newURL.absoluteString]];
					AssetCacheLog(@"Faking the Facebook Profile Image Lookup %@",newURL.absoluteString);
				}
				
				// By using this request format, we skip the cache normally
				NSURLRequest * cacheUpdateRequest = [NSURLRequest requestWithURL:newURL
																	 cachePolicy:NSURLRequestReloadIgnoringLocalCacheData
																 timeoutInterval:30];
				NSError * error;
				NSURLResponse * cacheUpdateResponse;
				NSData * theData = [NSURLConnection sendSynchronousRequest: cacheUpdateRequest
														 returningResponse: &cacheUpdateResponse
																	 error: &error];
				if (error){
					return;
				}
				NSCachedURLResponse * cacheable = [[NSCachedURLResponse alloc] initWithResponse: cacheUpdateResponse
																						   data: theData
																					   userInfo: @{ kFBSURLCacheDateSavedKey : [NSDate date] }
																				  storagePolicy: NSURLCacheStorageAllowed];
				[ImageAssetCache storeCachedResponse:cacheable forRequest:request];
			});
		}
		return cachedResponse;
	} storage:^(NSCachedURLResponse *response, NSURLRequest *request) {
		// Don't store this through the normal channels
		// This lets us more easily falsify the redirect so the smaller points at the larger FB image :D
	}];




	// Profile Image Cache
	__block NSError * error;
	NSRegularExpression *avatarRegex = [NSRegularExpression regularExpressionWithPattern:@"(/system/badges/icons/|/system/users/photos/|profile.*.fbcdn.net)+"
																				 options:0
																				   error:&error];
	[baseCache registerCacheInclusionFilter:^BOOL(NSURLRequest *request) {
		NSString *tmp;
		NSRange avatarRange = [avatarRegex rangeOfFirstMatchInString:(tmp = request.URL.absoluteString) options:0 range:NSMakeRange(0, tmp.length)];
		return avatarRange.location != NSNotFound;
	} lookup:^NSCachedURLResponse *(NSURLRequest *request) {
		NSCachedURLResponse * cachedResponse = [ImageAssetCache cachedResponseForRequest:request];
		NSDate * dateSaved = cachedResponse.userInfo[kFBSURLCacheDateSavedKey];
		
		if (cachedResponse && ![dateSaved isToday]) {
			// If we have a response in the cache, but it's not from today lets blindly update it :D
			dispatch_async(CONCURRENT_QUEUE, ^{
				AssetCacheLog(@"Updating cache for %@",request.URL.absoluteString);
				
				NSURLRequest * cacheUpdateRequest = [NSURLRequest requestWithURL:request.URL
																	 cachePolicy:NSURLRequestReloadIgnoringLocalCacheData
																 timeoutInterval:30];
				NSError * error;
				NSURLResponse * cacheUpdateResponse;
				NSData * theData = [NSURLConnection sendSynchronousRequest: cacheUpdateRequest
														 returningResponse: &cacheUpdateResponse
																	 error: &error];
				if (error){
					return;
				}
				NSCachedURLResponse * cacheable = [[NSCachedURLResponse alloc] initWithResponse: cacheUpdateResponse
																						   data: theData
																					   userInfo: @{ kFBSURLCacheDateSavedKey : [NSDate date] }
																				  storagePolicy: NSURLCacheStorageAllowed];
				[ImageAssetCache storeCachedResponse:cacheable forRequest:request];
			});
		}
		
		return cachedResponse;
	} storage:^(NSCachedURLResponse *response, NSURLRequest *request) {
		[ImageAssetCache storeCachedResponse:response forRequest:request];
  }];