nsurlsessionconfiguration

I have a test app setup and it successfully downloads content from the network even if the user switches apps while a download is in progress. Great, now I have background downloads in place. Now I want to add caching. There is no point to me downloading images more than once, b/c of system design, given an image URL I can tell you the content behind that URL will never change. So, now I want to cache the results of my download using apple's built in in-memory/on-disk cache that I've read so much about (as opposed to me saving the file manually in NSCachesDirectory and then checking there

I want to display file download progress (how many bytes are received) of particular file. It works fine with the NSURLSessionDownloadTask .My question is I want to achieve the same with the NSURLSessionDataTask. Here is the code which receives file into NSData and writes to document folder: NSURLSessionConfiguration *defaultConfigObject = [NSURLSessionConfiguration defaultSessionConfiguration]; NSURLSession *defaultSession = [NSURLSession sessionWithConfiguration: defaultConfigObject delegate: self delegateQueue: [NSOperationQueue mainQueue]]; NSURLSessionDataTask * dataTask = [defaultSession

Looking over the documentation of NSURLSession and NSURLSessionConfiguration , I was under the impression I should configure it with a dictionary like the following: // Create a dictionary to describe the proxy NSDictionary *proxyDict = @{ (NSString *)kCFProxyHostNameKey : @"myProxyHost.com", (NSString *)kCFProxyPortNumberKey : @"12345", (NSString *)kCFProxyTypeKey : (NSString*)kCFProxyTypeHTTP }; // Create a configuration that uses the dictionary NSURLSessionConfiguration *configuration = [NSURLSessionConfiguration defaultSessionConfiguration]; [configuration setConnectionProxyDictionary