How to persist a websocket connection using ControlChannelTrigger in the background?

Anonymous

Hello, I followed https://learn.microsoft.com/en-us/windows/uwp/networking/network-communications-in-the-background#controlchanneltrigger-with-websockets and create an out-of-process background task using ControlChannelTrigger with MessageWebSocket.

Everything works fine in the foreground, however, if I close the app window, the websocket connection will be killed and no longer receive any message.

I re-opened my app but found registered BackgroundTasks didn't exist any more and I had to register them again.

How can I persist a websocket connection using ControlChannelTrigger in the background?

Thanks!

Richard Zhang-MSFT 6,936 Reputation points

2020-02-24T03:31:15.39+00:00

Hi, Can you provide a minimum runnable demo? This will help us debug and resolve your issue. In addition, maybe this official example provided by Microsoft will help you, it shows how to create a StreamSocket that can still be active outside the application life cycle. Although it is different from WebSocket, the general process is the same and can be used as a reference.
Richard Zhang-MSFT 6,936 Reputation points

2020-02-26T08:35:08.463+00:00

Hello, may you please provide further information to help us solve the problem?
Anonymous

2020-02-26T08:36:29.143+00:00

Yes.
I can provide a minimal repro, but I cannot find a suitable websocket server for now...
Richard Zhang-MSFT 6,936 Reputation points

2020-02-26T09:05:51.407+00:00

You can refer to the example of StreamSocket I provided to create another Server project to run locally.
Anonymous

2020-02-26T09:29:59.383+00:00

Here's my repro project:

https://1drv.ms/u/s!ApWNk8G_rszRgcNpQj1O05OKbTog8Q?e=ZR36Rn
Richard Zhang-MSFT 6,936 Reputation points

2020-02-27T01:55:45.767+00:00

Hi, I tested your project and there are two main issues. The first point is that the full name of WebSocketKeepAlive is Windows.Networking.Sockets.WebSocketKeepAlive, not a class created by yourself. Regarding the inability to register the BackgroundTask, it seems to be caused by the Trigger, and there may be an exception during the creation of the channel. However, there is a known issue here. If you replace WebSocketKeepAliveTask to Windows.Networking.Sockets.WebSocketKeepAlive, the project cannot be generated correctly. For details, see this issue. Our engineer teams is currently working on this issue. If there something news, I will post it here.
Anonymous

2020-02-28T02:33:35.363+00:00

Thanks for your reply. I'll try again once the issue got fixed.
Richard Zhang-MSFT 6,936 Reputation points

2020-02-28T06:30:07.31+00:00

Sure, I will follow up on the content and if there have new progress I will post
Anonymous

2020-05-10T17:23:54.973+00:00

Hi, I've verified that the issue in https://github.com/MicrosoftDocs/windows-uwp/issues/2205 has been fixed in Windows 10 SDK 19624.

However, I still cannot persist a WebSocket connection using ControlChannelTrigger in the background. Every time when I close the app, the WebSocket connection will break unexpectedly.

Here's my new repro: https://1drv.ms/u/s!ApWNk8G_rszRgcZ_0wEDZ_LbWF8w9A?e=N5WhXO