Question

I’m unable to find error in this code:

-(void)downloadImageFromURL:(NSURL*)url withCompletionBlock:(RSSMessageImageDownloadCompletionBlock)completionBlock
{

    ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:url];

    __block RSSMessage *_self = self;
    request.completionBlock =
    ^{    
        __block NSData *responseData = request.responseData;

        dispatch_async( dispatch_get_main_queue(), ^{
            _self.image = responseData;            
            [[[UIApplication sharedApplication] delegate] saveContext];
            if(completionBlock != nil)
            {
                completionBlock();
            }

        });
    };

    [request startAsynchronous];
}

In this form I’ve got a memory leak from instruments. I was assuming it is because I’ve lacked the __block keyword before: ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:url];

But when I’ve added this keyword to above line I’ve got error like:

* -[NSConcreteMutableData isNSData__]: message sent to deallocated instance 0xdeab380

I do not know how to retain the request data and not leak memory.

Answer 1

from the docs:

- (IBAction)grabURLInBackground:(id)sender
{
   NSURL *url = [NSURL URLWithString:@"http://allseeing-i.com"];
   __block ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:url];
   [request setCompletionBlock:^{
      // Use when fetching text data
      NSString *responseString = [request responseString];

      // Use when fetching binary data
      NSData *responseData = [request responseData];
   }];
   [request setFailedBlock:^{
      NSError *error = [request error];
   }];
   [request startAsynchronous];
}

seems like the request itself needs to be marked with __block

---

Note, that the original author of ASIHTTPRequest isnt supporting it anymore. He explains his reasons very well and give links and suggestions for alternative projects. I am happy with AFNetworking, that has a great block based interface.