SignalR closes the connection within ReplayKit (RPBroadcastSampleHandler)

[wgcarvajal]

SignalR closes the connection within ReplayKit (RPBroadcastSampleHandler) when the application goes into the background, and this doesn't happen using others libraries like WebSocket or WebRTC. I was wondering if there's a way to do this with SignalR, or is it definitely not compatible with ReplayKit?

Thank you very much. I'll be waiting.

[moozzyk]

I have not used ReplayKit so I don't know the specifics but I don't think it is a ReplayKit compatibility issue. In general, when an application is sent to background it has very limited abilities to maintain network connections (or perform almost any task) unless it's an audio or VOIP application. Here are a couple posts with more details:

https://apple.stackexchange.com/questions/252239/do-ios-apps-run-in-the-background
https://developer.apple.com/forums/thread/685525/

I am not sure how ReplayKit can keep a WebSocket connection alive when the application is backgrounded. My understanding is that limiting network activity for backgrounded applications is an intended OS behavior. If ReplayKit can do it for WebSockets in general, it should be able to do this for this client as it is using WebSockets (the URLSessionWebSocketTask API) under the hood.

The client itself doesn't do anything that would force stopping the connection when the application is sent to background.

[wgcarvajal]

Thank you very much for responding.

First, let's clarify that ReplayKit is the only way to share the screen of an iOS device. It's widely used for video game streaming. We currently use the API for remote viewing iOS devices with WebSocket (specifically, URLSessionWebSocketTask). It works well for us. We've done proofs of concept with WebRTC, and it's also viable. However, we've encountered this issue with SignalR on iOS. The other two technologies don't close the connection when the app is minimized, as they run within ReplayKit's RPBroadcastSampleHandler, which runs in a separate thread from the app thread. This is the correct way to do it. We believe this use case is important for you to review, as ReplayKit is an option available on iOS. We're very interested in achieving this with SignalR and using this technology within our solution.

I forgot to share the device screen in general (not just the view of our application, but that of the entire device) the application would normally be in the background.

Thank you very much...

[moozzyk]

Please provide logs collected at the debug level and a repro I could use to reproduce the problem.