cocoa touch - Is it possible to prevent an NSURLRequest from caching data or remove cached data following a request?

Question

On iPhone, I perform a HTTP request using NSURLRequest for a chunk of data. Object allocation spikes and I assign the data accordingly. When I finish with the data, I free it up accordingly - however instruments doesn't show any data to have been freed!

My theory is that by default HTTP requests are cached, however - I don't want my iPhone app to cache this data.

Is there a way to clear this cache after a request or prevent any data from being cached in the first place?

I've tried using all the cache policies documented a little like below:

NSMutableURLRequest *theRequest = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:url]];
theRequest.cachePolicy = NSURLRequestReloadIgnoringLocalCacheData;

but nothing seems to free up the memory!

Answer 1

Usually it's easier to create the request like this

NSURLRequest *request = [NSURLRequest requestWithURL:url
      cachePolicy:NSURLRequestReloadIgnoringCacheData
      timeoutInterval:60.0];

Then create the connection

NSURLConnection *conn = [NSURLConnection connectionWithRequest:request
       delegate:self];

and implement the connection:willCacheResponse: method on the delegate. Just returning nil should do it.

- (NSCachedURLResponse *)connection:(NSURLConnection *)connection willCacheResponse:(NSCachedURLResponse *)cachedResponse {
  return nil;
}