iPhone NSURLConnection - delegates not working

Question

Hello- I am trying to get an NSURLConnection to work in my app. I have followed apple's code almost exactly but it doesn't seem to work. The NSURLConnection is inside of a method called, downloadSave. This method runs properly through the end, and my log indicates, "Connection Exists" - however nothing happens after that as if none of the delegate methods get called.

NSAutoreleasePool* pool = [[NSAutoreleasePool alloc] init];

    NSString *tempString = [[NSString alloc]initWithFormat:@"http://www.myWebsite.com/%@.jpg",chartFileName];
    NSURLRequest *theRequest=[NSURLRequest requestWithURL:[NSURL URLWithString:tempString]
                                              cachePolicy:NSURLRequestUseProtocolCachePolicy
                                          timeoutInterval:10.0];


    NSURLConnection *theConnection=[[NSURLConnection alloc] initWithRequest:theRequest delegate:self];
    if (theConnection) {


        mutableData = [[NSMutableData data] retain];
        self.image = nil;
        NSLog(@"connection exists");


    } else {
        UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"Connection Error" message:@"There was an error contacting the servers. Please try again." delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
        [alert show];
        [alert release];
        [activityIndicator stopAnimating];


    }

    [pool drain];
    [pool release];
}

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{

    NSLog(@"got to connection did receive response");
    [mutableData setLength:0];
}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{

    [mutableData appendData:data];
    NSLog(@"got some data were at %i",mutableData.length);
}


- (void)connection:(NSURLConnection *)connection
  didFailWithError:(NSError *)error
{

    [connection release];
    // receivedData is declared as a method instance elsewhere
    self.mutableData = nil;

    NSLog(@"Connection failed! Error - %@ %@",
          [error localizedDescription],
          [[error userInfo] objectForKey:NSErrorFailingURLStringKey]);
}


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

    NSLog(@"Succeeded! Received %d bytes of data",[mutableData length]);

//more code follows to display the downloaded image

}

The only thing that appears in the log is: "Connection Exists"

Answer 1

I can only guess by your code that downloadSave in called in a separate thread as you have an NSAutoReleasePool (not saying thats what your doing but its likely). NSURLConnection can only respond to the delegate methods in the main thread when it is initialised in the main thread.

As NSURLConnection already is a threaded delegate call you shouldn't need to create it in thread. If you need to thread it for some reason you should be able to use

NSError *error;
NSURLResponse *response;
NSData *connectionData = [NSURLConnection sendSynchronousRequest:theRequest returningResponse:&response error:&error];

And that should return the data to the child thread.