NSNetService delegates not being called

Question

I'm trying to resolve a NSNetService (named "My_Mac") to an IP in a background app with this code:

NSNetService *service = [[NSNetService alloc] initWithDomain:@"local." type:@"_daap._tcp" name:@"My_Mac"];
[service setDelegate:self];
[service resolveWithTimeout:5];

And in the same class, I have these delegate methods defined:

- (void)netServiceDidResolveAddress:(NSNetService *)sender
- (void)netService:(NSNetService *)sender didNotResolve:(NSDictionary *)errorDict

Here's the strange part: neither delegate methods get called unless I run a NSAlert after "[service resolveWithTimeout:5];". Any ideas?

Answer 1

I'm not sure, but it looks like the request is not actually scheduled in a run loop for some reason. Maybe try something like this to schedule it?

NSNetService *service = [[[NSNetService alloc] initWithDomain:@"local." type:@"_daap._tcp." name:@"My_Mac"] autorelease];
[service setDelegate:self];
[service scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:@"PrivateMyMacServiceMode"];
[service resolveWithTimeout:8.0];

Stupid question, but are you explicitly implementing NSServiceDelegate protocol or just have the methods?

EDIT: I had another thought that this might be some kind of race condition (a more likely scenario). Delegates are usually weak references. If your object is dropping out of scope and being autoreleased, the system would end up with a nil handle and be firing the messages to nil. In the case where you show an NSAlert (or do other work) your object might be hanging around just long enough for it to get the messages fired back to it. Could you confirm your object sticks around for the full 8 seconds?

Answer 2

Thank you, I never cease to be amazed at how often Stack Overflow has the -exact- question I'm having at the moment - for me, an explicit retain did it!

Thanks!