Make the delegate public so it can be set.

[onato]

When a subscription already exists I get it with client.getSubscription. The returned subscription's delegate then needs to be set. In order to do this, the delegate needs to be public.

[FZambia]

@onato hello, thanks!

Just want to clarify a use case. So you want to modify delegate behaviour for the existing subscription? Can't you just put the required logic into original delegate implementation passed during Subscription creation time?

[onato]

In my case, not really. I recreate the delegate regularly. This means the delegate is nil when I call getSubscription.

I use the subscription on a detail screen that subscribes to different channels based on its ID. I don't want to keep subscriptions for screens that are no longer around, so I removeSubscription them when I deinit the screen. It shouldn't, given my use-case, but I have seen newSubscription throw a CentrifugeError.duplicateSub. I am using getSubscription to recover. This could be caused by a UISplitViewController keeping a view controller around that is not onscreen. When I reopen that screen I briefly have two screens open that want to be subscribed to the same channel.

I am a little unclear as to how things are intended to be architected so I might be swimming upstream a little. Re-setting the delegate does seem to get things working as I expect.

[FZambia]

I think re-setting delegate without full understanding of the underlying problem isn't a good thing to do. This can cause some scary bugs if not accurately used, and I suppose modifying it should be synchronised with internal code that tries to access delegate methods.

If you call removeSubscription and later newSubscription then I believe library should not throw duplicateSub exceptions since removeSubscription removes Subscription from internal registry – and does this under lock.

So hoping on your help here to find out the reason why this happens in your application, with a simple example that reproduces a problem will be much easier to reason about the right fix 🙏

[onato]

I haven't been able to reliably reproduce my problem. I call client?.removeSubscription(subscription) when the app receives either of…

• UIApplication.didEnterBackgroundNotification
• UIApplication.willTerminateNotification

This should mean the subscription is always removed from the internal registry and it generally works as expected. Occasionally, I am getting duplicateSub errors though, so in the catch block, I'm then getting the existing subscription with getSubscription.

[onato]

I found the issue. I was subscribing on didBecomeActive instead of willEnterForeground which doesn't balance with didBecomeActive