Asynchronous URL GET Request with Response

NSURL *url=[NSURL URLWithString:[NSString stringWithFormat:@"%@webservice.php?param1=%@&param2=%@",kServerName, param1, param2]];
NSURLRequest *request=[NSURLRequest requestWithURL:url];
NSOperationQueue *queue = [[[NSOperationQueue alloc] init] autorelease];
[NSURLConnection sendAsynchronousRequest:request queue:queue completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
if ([data length] >0 && error == nil)
{
// if response is a string
NSString *responseString=[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
// if response is JSON Array
NSMutableArray *array=[NSMutableArray arrayWithArray:[NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers error:nil]];
// if response is JSON Object
NSMutableDictionary *dictionary=[NSMutableDictionary dictionaryWithDictionary:[NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers error:nil]];
}
else if ([data length] == 0 && error == nil)
{
NSLog(@"Nothing was downloaded.");
}
else if (error != nil)
{
NSLog(@"Error happened = %@", error);
}
}];