Question

I’m making an NSURLConnection to my server but responseData ends up being null in connectionDidFinishLoading and I can’t figure out why. Here’s the code for the connection:

NSMutableData *responseData;

- (void)myFunction:(id)sender {

  NSString *url = @"http://www.example.com/";

  NSURL *URL = [NSURL URLWithString:url];

  NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:URL cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:30.0];

  NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];

  [connection start];
}


// NSURLConnection Delegates
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
  [responseData setLength:0];
}


- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
  [responseData appendData:data];
}


- (void)connectionDidFinishLoading:(NSURLConnection *)connection {

} // end connectionDidFinishLoading

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
  NSLog(@"Connection error: %@",[error description]);
}

Answer 1

Typical! Just as I finished posting the question the answer dawned on me. I never initialized responseData. So in viewDidLoad I added the line below:

- (void)viewDidLoad
{

  [super viewDidLoad];

  responseData = [NSMutableData data];

}