SoapCore WCF C# program using XmlSerializer doesn't create the WSDL with async methods with CancellationToken

Question

I have an issue in async WCF service using SoapCore in .Net 6 using a cancellation token and XmlSerializer serializer.

The detailed WCF application is as follows:

• WCF service in C# .Net Core 6 using SoapCore NuGet package using SoapSerializer.XmlSerializer serializer
• I created an async method that has the [OperationContract] attribute with a CancellationToken parameter
• I try to get the WSDL using the URL https://localhost:7026/Services.svc?WSDL and it fails because of the CancellationToken with the exception ArgumentException: .NET type CancellationToken cannot be resolved into XML schema type (CancellationToken has namespace starting with System (System.Threading.CancellationToken), is a structure (value type), and is categorized by SoapCore code as very similar to bool, int, long, ... and tries to generate an XML for it and it fails)
• I tried adding the [XmlIgnore] attribute to the parameter CancellationToken of the method having the [OperationContract] attribute and it doesn't work
• [MessageContract(IsWrapped = false)] cannot be added to parameters of methods

Note: This works with SoapCore with SoapSerializer.DataContractSerializer serializer, but the generated WSDL is bigger enumerating many basic types that I don't use and I want to use SoapSerializer.XmlSerializer if possible.

Program.cs code:

using Microsoft.Extensions.DependencyInjection.Extensions;
using SoapCore;

namespace TestSoapCore;

public static class Program
{
    public static void Main(string[] args)
    {
        var builder = WebApplication.CreateBuilder(args);
        builder.Services.AddSoapCore();
        builder.Services.TryAddSingleton<MyService>();
        builder.Services.AddMvc();

        var app = builder.Build();
        app.UseRouting();
        app.UseEndpoints(endpoints =>
        {
            endpoints.UseSoapEndpoint<MyService>(
                "/Services.svc",
                new SoapEncoderOptions(),
                SoapSerializer.XmlSerializer
                // This works with SoapSerializer.DataContractSerializer but I prefer SoapSerializer.XmlSerializer if possible
            );
        });
        app.Run();
    }
}

Contract.cs code:

using System.Runtime.Serialization;

namespace TestSoapCore;

[DataContract]
public class Contract {
    [DataMember]
    public string? TestProperty { get; set; }
}

MyService.cs code:

using System.ServiceModel;
using System.Xml.Serialization;

namespace TestSoapCore;

[ServiceContract]
public class MyService
{
    [OperationContract]
    public async Task<string> Test(
        Contract contract,
        // [MessageContract(IsWrapped = false)] cannot be added to parameters
        [XmlIgnore] // This doesn't work
        CancellationToken cancellationToken)
    {
        cancellationToken.ThrowIfCancellationRequested();

        return contract?.TestProperty + "2";
    }
}

Full exception while getting the WSDL at https://localhost:7026/Services.svc?WSDL when SoapSerializer.XmlSerializer serializer is used:

How the WSDL works with SoapSerializer.XmlSerializer serializer without any CancellationToken (but I want the CancellationToken for async methods, it is better to have it):

How the WSDL is bloated and has many basic types I don't use when SoapSerializer.DataContractSerializer serializer is used (that's why I still prefer SoapSerializer.XmlSerializer if possible):

• Part 1:
• Part 2:
• Part 3:
• Part 4:

Answer 1

Because the CancellationToken is not working very well with WCF using SoapCore (SoapSerializer.XmlSerializer serializer doesn't generate the WSDL because of CancellationToken and SoapSerializer.DataContractSerializer serializer puts the CancellationToken as an object that needs to be sent with many properties and their types) I ended up removing the CancellationToken entirely and I used the SoapSerializer.XmlSerializer to have less data (WSDL not bloated with all the unused types, many pages of useless data).

PS: This is how the CancellationToken looks with SoapCore and SoapSerializer.DataContractSerializer serializer (not very nice..):

Answer 2

If You want to get SoapCore working with cancellation token there is another approach. SoapCore allows us to define ServiceOperationTuner which can read the cancellationToken from HttpContext and than assign it to service. The example bellow explains the idea of sollution

Define service operation tuner

public class ServiceOperationTuner : IServiceOperationTuner
{
    public void Tune(HttpContext httpContext, object serviceInstance, OperationDescription operation)
    {
        if (serviceInstance != null && serviceInstance is MyService)
        {
            MyService service = serviceInstance as MyService;
            service.SetCancellationToken(httpContext.RequestAborted);
        }
    }
}

Add service operation tuner in Program

builder.Services.AddSoapServiceOperationTuner(new ServiceOperationTuner());

Modify MyService in order to get cancellationToken

public class MyService
{
    
    CancellationToken _cancellationToken;
        
    public void SetCancellationToken(CancellationToken cancellationToken)
    {
        _cancellationToken = cancellationToken;
    }

Answer 3

Like Aleksander Ch response, but mixed with the example of official page

Interface

[ServiceContract]
public interface IService
{
    public void SetCancellationToken(CancellationToken cancellationToken);

    [OperationContract]
    public Task<int> CheckStatus();
}

Service (Very important ThreadLocal variable)

public sealed class Service : IService
{
    private readonly ThreadLocal<CancellationToken> _threadCancellationToken = new();

    Task<int> ILectoService.CheckStatus()
    {
        if (_threadCancellationToken.IsValueCreated)
            _threadCancellationToken.Value.ThrowIfCancellationRequested();
        ........
    }

    void ILectoService.SetCancellationToken(CancellationToken cancellationToken)
    {
        _threadCancellationToken.Value = cancellationToken;
    }
}

ServiceOperationTuner

internal sealed class ServiceOperationTuner : IServiceOperationTuner
{
    public void Tune(HttpContext httpContext, object serviceInstance, SoapCore.ServiceModel.OperationDescription operation)
    {
        if (serviceInstance is IService service)
        {
            service.SetCancellationToken(httpContext.RequestAborted);
        }
    }
}

Add service operation tuner in Program

builder.Services.AddSoapServiceOperationTuner(new ServiceOperationTuner());