VoIP with PushKit

Hi,

Pushkit Notifications should not be used for long running background work.

Also they only should be used by VOIP apps(others will be declined).

If you have a VOIP app which can use pushkit there is a simple solution:

The notification should create a background task which downloads the file see https://developer.apple.com/library/ios/documentation/iPhone/Conceptual/iPhoneOSProgrammingGuide/BackgroundExecution/BackgroundExecution.html

If you don't have a VOIP app you have to work around that problem with silent notifications which are not guaranteed to arrive(also Pushkit is also not guaranteed with iOS 8).

So without VOIP priviliges you have to work around this problem to get the user to open the app so you can create a background task.

It is a VoIP application so it is authorized to use PushKit.

There is no problem to start a long background task.

However the background transfer service should work also. But this download method is supposed to be optimized for grouping download to save battery.

However when I tried PushKit, I faced many issues.

Especially the didReceiveIncomingPushWithPayload is not called any more after some times.

(Sometimes after many days working well)

Did it work for you ?

What I figured out is that not every voip push notification that has been sent by the server will be received by the iOS device. Sometimes it seems, that they got lost.

My app won't be put into the app store, so it is ok, that the app is marked to be a voip app without being a normal voip app.

I'm using the voip feature to be able to receive push notifications in all app states - including the suspended state. The notifications will be received even on the lock screen. But this worked sometimes and sometimes not, I cannot figured out why this happens. I found the following posting in the iOS dev forum archives (https://devforums.apple.com/thread/257354?start=0&tstart=0), but I haven't tested this solution yet. I agree with you, I faced many issues as well using PushKit.

My problem is still starting a background task, when a voip push notification arrives, the app is suspended and the lock screen is in front. In this case I register a new background task to download a file from a remote server. Therefore I'm using the NSUrlSessionDownloadDelegate - this works perfectly if the app is suspended and the device is unlocked. In locked mode the download starts but ended immeditely with the error "lost connection to background transfer service". I cannot find a solution for this error.

Pushkit seems to be buggy, a lot of developers are reporting that it stops working after some time so you should not use it yet.

Argh, ok, it seems you're right.

I'm wondering why apple publishes such a buggy library.

Anyway, I'll will use the "old" approach using SetKeepAliveTimeout.

Thanks!

The old approach requires you to have a server maintaining a connection if you want to be notified immediately.

Additionnaly the app won't be restarted if it has been killed.