NSStream and Sockets, NSStreamDelegate methods not being called

Question

I\'ve followed the guide Setting Up Socket Streams and have effectively duplicated that code in my class. No matter what I try the delegate methods just don\'t seem to get c

Answer 1

In the lines like this:

[inputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];

Instead of using [NSRunLoop currentRunLoop] I changed it to [NSRunLoop mainRunLoop].

EDIT 2011-05-30:

The reason this did not work is because I was setting up the sockets in a background thread via +[NSThread detachNewThreadSelector:toTarget:withObject:].

Doing it that way created a new run loop, which after reading the run loop developer documentation I discovered that you need to tell the NSRunLoop to run manually.

Running it in the same run loop as the main thread was fine on performance, though I was able to squeeze a bit more performance out by writing a wrapper class and running all network I/O on a background thread.

Answer 2

That solution will work if & only if you don't have blocking work on thread 0. This is often OK, but a better solution is to create a new thread (i.e. using a class method to create the thread on demand) and then enqueue on that thread. i.e.

+ (NSThread *)networkThread {
    static NSThread *networkThread = nil;
    static dispatch_once_t oncePredicate;

    dispatch_once(&oncePredicate, ^{
        networkThread =
             [[NSThread alloc] initWithTarget:self
                                     selector:@selector(networkThreadMain:)
                                       object:nil];
        [networkThread start];
    });

    return networkThread;
}

+ (void)networkThreadMain:(id)unused {
    do {
        @autoreleasepool {
            [[NSRunLoop currentRunLoop] run];
        }
    } while (YES);
}

- (void)scheduleInCurrentThread
{
    [inputstream scheduleInRunLoop:[NSRunLoop currentRunLoop]
                           forMode:NSRunLoopCommonModes];
}

With this, you can schedule the input stream using:

[self performSelector:@selector(scheduleInCurrentThread)
             onThread:[[self class] networkThread]
           withObject:nil
        waitUntilDone:YES];

This will allow you to run your network operations without worrying about deadlocks anymore.