[BUG] CreateAppleTemplateRegistrationAsync throws an exception on .NET Maui (.NET 8)

[juniorsaraviao]

Describe the bug
I'm currently migration a .NET Maui app from .NET 7 to .NET 8. I'm currently using Microsoft.Azure.NotificationHubs v4.2.0 but the app crashes while using CreateAppleTemplateRegistrationAsync

Exception or Stack Trace

[17:22:34 ERR] Error in line 1 position 1029. 'Element' 'DeviceToken' from namespace 'http://schemas.microsoft.com/netservices/2010/10/servicebus/connect' is not expected. Expecting element 'PushVariables'.

To Reproduce

• Create a .NET Maui app (.NET 8)
• Follow the steps to create a template registration (link)

Code Snippet

string APNTemplateBody = "{\"aps\":{\"alert\":{\"title\":\"$(title)\",\"body\":\"$(message)\"}}}";

if (string.IsNullOrEmpty(DeviceTokenForiOS))
{
    return;
}

var registrationId = Preferences.Get(registration_id, string.Empty);
if (!string.IsNullOrEmpty(registrationId))
{
    await hub.DeleteRegistrationAsync(registrationId);
}

var tags = new string[] { tag + userId };
var newRegistration = await hub.CreateAppleTemplateRegistrationAsync(DeviceTokenForiOS, EnvironmentConstants.APNTemplateBody, tags);
Preferences.Set(registration_id, newRegistration.RegistrationId);

Expected behavior
The CreateAppleTemplateRegistrationAsync should register the template without any issues. Using the same code in .NET Maui (.NET 7) works as expected.

Setup (please complete the following information):

• OS: Mac book Pro - MacOS (Sonoma 14.5)
• IDE : Visual Studio for Mac 17.6.13
• Version of the Library used: Microsoft.Azure.NotificationHubs v4.2.0

Information Checklist
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• [yes] Bug Description Added
• [yes] Repro Steps Added
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[Hamata6]

I have the same issue. It suddenly happened. One week ago, my code worked, and last Thursday/Friday I did not change any code and I get this error message.
It has something to do with the response that the package receives from Azure, because the registration (in my case) IS made. So the call is successful, but the NuGet Package can't parse the response (I think).
EDIT: Can't guarantee my above statement is true, may be an already existing registration.

@TAbbott117 I saw you replying on an other issue, so I tag you, because now the whole package is not working
@aimankhan I found you as a contributor specialized in Notification Hub, so tagged you too.

BTW, the calls for Android stuff are working fine, no exceptions on those method calls. Only the Apple calls are returning this exceptions

[alexgavru]

I have the exactly the same issue, it started happening after the pipeline workloads automatically updated some sdks (with red are the new values):

[alexgavru]

I found a shady workaround for this issue. I integrated the NotificationHubs project directly into my solution and modified the AppleRegistrationDescription at runtime. I added the PushVariables element before the DeviceToken element:

Steps:

1. Integrate this repo directly into your project and remove the nuget dependencies.
2. Update all the nuggets in the project to latest versions
3. In NotificationHubClient.cs in methods ReadEntitiesAsync(Stream source) and ReadEntityAsync(Stream source). Basically read the stream, parse the xml and detect if PushVariables is not there and add it, then pass a new stream based on the modification you just made.

I didn't investigate to see why the error is there, at first sight it seems that something is not working right in the System.Serialization or XMLSerializer, because it doesn't take into account that PushVariables element is optional/not required. Hence the fix to add an empty PushVariables element if it doesn't exist.

[Hamata6]

It doesn't seem like we are getting a response here. I just checked and it still crashes. What to do? Submit the bug elsewhere? But where?
@TAbbott117 @aimankhan @pmngo @jessHuh

[juniorsaraviao]

any updates on this issue?

[alexgavru]

Good news, with the latest workloads, it started working again. I reverted my workaround.

[nacho-herrera-appspace]

Hi!
I just tried the latest workload and got the following exception.

• iOS workload version: 17.5.8020
• Microsoft.Azure.NotificationHubs library version: 4.2.0

System.Runtime.Serialization.SerializationException: ErrorInLine, 1, 1098 UnexpectedElementExpectingElements, Element, DeviceToken, http://schemas.microsoft.com/netservices/2010/10/servicebus/connect, PushVariables

[alexgavru]

I did a complete cleanup of my environment. Deleted dotnet folder, installed 8.0.401 .NET SDK, and ran command: "sudo dotnet workload install maui". Workaround was not needed anymore for me.
For now it seems to work, I can let you know later this month once we release this to production if it went well or not. :)

[Toine-db]

Same issue here

RegisteredForRemoteNotifications Exception: System.Runtime.Serialization.SerializationException: Error in line 1 position 1009. 'Element' 'DeviceToken' from namespace 'http://schemas.microsoft.com/netservices/2010/10/servicebus/connect' is not expected. Expecting element 'PushVariables'.

Reinstalled dotnet 8.0.402 (version newer) and did dotnet workload install maui... > resulting in MAUI 8.0.82/8.0.100
Besides that I work with

• XCode 16.0
• Microsoft.Azure.NotificationHubs 4.2.0

[Toine-db]

I found a workaround, for my use case....but there are still issue in this repo when 'PushVariables' or 'Tags' aren't used.

var appleRegistration = new AppleRegistrationDescription(token, tags);
appleRegistration.PushVariables = new Dictionary<string, string>()
{
     { "azure_notificationhubs_dotnet_issue", "missing PushVariables fix" }
};
var registration = await hub.CreateRegistrationAsync(appleRegistration);

Currently im always re-creating a registration, instead of retrieving an old one. Because methods like GetRegistrationsByChannelAsync do get the same errors, and by removing old registrations and re-creating new, it won't get the errors.