Requesting push notification channel on a background task throws COMException

[Diegorro98]

Describe the bug

I'm trying to create a flow where a background task updates the push notification channel when the app is updated. The background task runs fine, but when the task calls to CreateChannelAsync, it produces the following exception:

'System.Runtime.InteropServices.COMException' at WinRT.Runtime.dll
WinRT Info: Unspecified Error

Steps to reproduce the bug

In a project with a background task, in the background task project:

1. Install WindowsAppSDK NuGet
2. Set the content of the Run method to the following:

public async void Run(IBackgroundTaskInstance taskInstance)
{
        var deferral = taskInstance.GetDeferral();
        try
        {
            if (PushNotificationManager.IsSupported())
            {
                var remote_id = "7edfab6c-25ae-4678-b406-d1848f97919a";  // Replace this with your own Azure ObjectId
                var channelOperation = PushNotificationManager.Default.CreateChannelAsync(new(remote_id));
                channelOperation.Progress = (sender, args) =>
                {
                    if (args.status == PushNotificationChannelStatus.InProgress)
                    {
                        Debug.WriteLine($"Channel request is in progress.");
                    }
                    else if (args.status == PushNotificationChannelStatus.InProgressRetry)
                    {
                        Debug.WriteLine($"The channel request is in back-off retry mode because of a retryable error");
                    }
                };
                var requestTask = channelOperation.AsTask();
                var completedTask = await Task.WhenAny(requestTask, Task.Delay(300000));
                if (completedTask != requestTask)
                {
                    Debug.WriteLine($"Channel request timeout.");
                    return null;
                }
                var result = channelOperation.GetResults();
                if (result.Status == PushNotificationChannelStatus.CompletedSuccess)
                {
                    return result.Channel;
                }
                else if (result.Status == PushNotificationChannelStatus.CompletedFailure)
                {
                    Debug.WriteLine($"Critical non-retryable error with channel request!");
                    return null;
                }
                else
                {
                    Debug.WriteLine($"Some failure occurred while requesting push channel.");
                    return null;
                }
            }
        }
        catch (Exception)
        {
        }
        finally
        {
            deferral.Complete(); 
        }
}

Expected behavior

It should get the channel URI when the background task is executed so that when the app is updated, because the channel is expired, the channel can be updated automatically.
It should get it just like it does with the same instructions at the main app project, which works fine and creates a channel that allows me to send push notifications by following the instructions from this resource: Quickstart: Push notifications in the Windows App SDK

NuGet package version

Windows App SDK 1.3.2: 1.3.230602002

Packaging type

Packaged (MSIX)

Windows version

Insider Build (10.0.22631)

IDE

Visual Studio 2022

Additional context

I also tried with PushNotificationChannelManager:

await PushNotificationChannelManager.CreatePushNotificationChannelForApplicationAsync();

and

await PushNotificationChannelManager.CreatePushNotificationChannelForApplicationAsync(remote_id);

The first option was able to return an URI, but when trying to send the notification, it returned a 403 HTTP error. The second raised the following exception:

'System.Runtime.InteropServices.COMException' at System.Private.CoreLib.dll
Element not found. (0x80070490)

I got the idea to update the push notification channel when the update task is triggered from this resource: Run background task when your UWP app is updated

[Diegorro98]

@bpulliam Any updates on this? I need a way to update the channel whenever the app updates (so the update background task is launched).
Another idea I had was to use Launcher.LaunchUriAsync to open the app and update the registration, but it raises an InvalidOperationException...

[Diegorro98]

Btw, inspecting a little bit deeper the stack trace, I realized that the exception is launched when using PushNotificationManager.Default (So Default getter is called).
Stacktrace:

at WinRT.ExceptionHelpers.< ThrowExceptionForHR>g_Throw|39_0(Int32 hr)
at WinRT.ExceptionHelpers.ThrowExceptionForHR(Int32hr)
at ABI.Microsoft.Windows.PushNotifications.IPushNotificationManagerStaticsMethods.get_Default(IObjectReference _obj)
at Microsoft.Windows.PushNotifications.PushNotificationManager.get_Default()
at App.BackgroundTasks.BackgroundTask.Run(IBackgroundTaskInstance taskInstance)

[Diegorro98]

Does not work neither with the added way of creating and registering background tasks at 1.7-experimental1

Also, for context, it does work when it is run inside a background task registered with Windows.ApplicationModel.Background.BackgroundTaskBuilder, when the background task is registered using Microsoft.Windows.ApplicationModel.Background.BackgroundTaskBuilder, then the push channel request does not work because the COMException is raised

[mominshaikhdevs]

@godlytalias

[godlytalias]

@Diegorro98 I will have a look into this and get back, Whether it means SetTaskEntryPointClsid of both namespace are behaving differently? Ideally that should not happen because the execution happens on another instance of the app process in both cases and the job of background task framework is to just initiate the process when trigger occurs. Is there a sample to figure out what you're trying?

[Diegorro98]

Sorry for the delay, it's been a busy week.
I did a little bit of more testing, at it seems the problem was originated in another place.

Then with the new task builder at 1.7 I can request a push channel in all task, which is cool because the use case for this is to keep updated the push channel and avoid a case where the devices does not longer receive updates

[godlytalias]

Thanks @Diegorro98 for the update

cc: @sharath2727