Integrating Reachability with ReactiveCocoa?

Question

I'm working on the development of an app using ReactiveCocoa and the time has came to integrate Reachability to handle Network Events.

I'm not sure about the work I've done as some of RAC design guidelines advice against it. But from what I've been researching I couldn't find a proper way to manage this (or more likely, I dind't understand how).

Our idea is to have a unique signal that sends events upon Reachability's notifications. Each of our viewcontrollers would subscribe to that signal and react each one in its specific way (ie alertview, do nothing, etc).

The thing is that we only need our visible viewcontroller to react, so we are using RACDisposable. This way, when a viewcontroller appears it subscribes to the signal, and when it dissapears we dispose it.

From the Design Guidelines of RAC the use of RACDisposable should be avoided, but I can't manage to handle this subscribe/unsubscribe cycle in any other way.

Is this approach correct for this kind of "infinite" signals?

An alternative we though of is using a signal that removes its previous subscribers when a new one joins. Does such a thing exist?

Thanks in advance for any light you can point in my direction.

---

From this SO post I got to trying takeUntil:[self rac_willDeallocSignal]which seems useful in theory but doesn't really work for me. As this behaviour is encapsulated within a Manager, and it's not supposed to be deallocated, I don't know how this can work in my favour.

An option that crossed my mind is takeUntila new signal fires whenever a method to stop is called; but it seems pretty much just so we don't use RACDisposable.

Answer 1

From this SO post I got to trying takeUntil:[self rac_willDeallocSignal]which seems useful in theory but doesn't really work for me. As this behaviour is encapsulated within a Manager, and it's not supposed to be deallocated, I don't know how this can work in my favour.

Your view controller can do something like this:

- (void)viewWillAppear
{
    RACSignal *disappear = [self rac_signalForSelector:@selector(viewWillDisappear)];
    [[self.manager.reachabilitySignal takeUntil:disappear] subscribeNext:^(id status) {

        // do whatever needs doing with reachability status here

    }];
}

and your Manager's reachabilitySignal can be implemented to register/de-register for reachability status changes as needed depending on whether there are any subscribers.