objective c - NSURLConnection didReceiveData not called

Question

I've read through tons of messages saying the same thing all over again : when you use a NSURLConnection, delegate methods are not called. I understand that Apple's doc are incomplete and reference deprecated methods, which is a shame, but I can't seem to find a solution.

Code for the request is there :

// Create request
NSURL *urlObj = [NSURL URLWithString:url];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:urlObj cachePolicy:NSURLRequestReloadIgnoringCacheData timeoutInterval:30];
[request setValue:@"gzip" forHTTPHeaderField:@"Accept-Encoding"];

if (![NSURLConnection canHandleRequest:request]) {
    NSLog(@"Can't handle request...");
    return;
}

// Start connection
dispatch_async(dispatch_get_main_queue(), ^{
    self.connection = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:YES]; // Edited
});

...and code for the delegate methods is here :

- (void) connection:(NSURLConnection *)_connection didReceiveResponse:(NSURLResponse *)response {
    NSLog(@"Receiving response: %@, status %d", [(NSHTTPURLResponse*)response allHeaderFields], [(NSHTTPURLResponse*) response statusCode]);
    self.data = [NSMutableData data];
}

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

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

- (void)connectionDidFinishDownloading:(NSURLConnection *)_connection destinationURL:(NSURL *) destinationURL {
    NSLog(@"Connection done!");
    [self _finish];
}

There's not a lot of error checking here, but I've made sure of a few things :

• Whatever happens, didReceiveData is never called, so I don't get any data
• ...but the data is transfered (I checked using tcpdump)
• ...and the other methods are called successfully.
• If I use the NSURLConnectionDownloadDelegate instead of NSURLConnectionDataDelegate, everything works but I can't get a hold on the downloaded file (this is a known bug)
• The request is not deallocated before completion by bad memory management
• Nothing changes if I use a standard HTML page somewhere on the internet as my URL
• The request is kicked off from the main queue

I don't want to use a third-party library, as, ultimately, these requests are to be included in a library of my own, and I'd like to minimize the dependencies. If I have to, I'll use CFNetwork directly, but it will be a huge pain in the you-know-what.

If you have any idea, it would help greatly. Thanks!

Answer 1

I ran into the same problem. Very annoying, but it seems that if you implement this method:

- (void)connectionDidFinishDownloading:(NSURLConnection *)connection destinationURL:(NSURL *)destinationURL

Then connection:didReceiveData: will never be called. You have to use connectionDidFinishLoading: instead... Yes, the docs say it is deprecated, but I think thats only because this method moved from NSURLConnectionDelegate into NSURLConnectionDataDelegate.