NSNetService doesn't contain any addresses - ios

Question

I'm hosting a service in a Mac application and connecting with an iOS app. While the iOS app will find the service, the service doesn't contain any addresses, so I can't connect a socket.
This is my hosting code on the Mac:
- (void)start {
queue = dispatch_queue_create("KeyboardServer", DISPATCH_QUEUE_CONCURRENT);
socket = [[GCDAsyncSocket alloc] initWithDelegate:self delegateQueue:queue];
NSError *error = nil;
if ([socket acceptOnPort:0 error:&error]) {
service = [[NSNetService alloc] initWithDomain:#"local." type:#"_probonjore._tcp." name:#"TestServer" port:[socket localPort]];
service.delegate = self;
[service publish];
} else {
NSLog(#"Unable to create server");
}
}
This is the connecting code on iOS:
- (BOOL)connectToServer:(NSNetService *)service {
NSArray *addresses = service.addresses;
socket = [[GCDAsyncSocket alloc] initWithDelegate:self delegateQueue:queue];
for (NSData *address in addresses) {
NSError *error;
if ([socket connectToAddress:address error:&error]) {
NSLog(#"Socket connected!");
return true;
}
}
return false;
}
The problem is, service.addresses is always empty and the loop instantly exits.

Answer 1

For anyone curious, I searched around and found a solution.
In the
- (void)netServiceBrowser:(NSNetServiceBrowser *)browser didFindService:(NSNetService *)service moreComing:(BOOL)moreComing
function, you need to:
Add the service to an array to stop the object being deallocated as soon as it goes out of scope
Set the delegate on the object so that you can respond to its address resolution
Call the function to make it resolve
Which looks like this:
- (void)netServiceBrowser:(NSNetServiceBrowser *)browser didFindService:(NSNetService *)service moreComing:(BOOL)moreComing {
NSLog(#"Found Service %#", [service name]);
[services addObject:service];
[service setDelegate:self];
[service resolveWithTimeout:5.0f];
}
You then want to implement
- (void)netService:(NSNetService *)sender didNotResolve:(NSDictionary *)errorDict
and
- (void)netServiceDidResolveAddress:(NSNetService *)service
To catch when the address either resolves or doesn't resolve.