Internal NullReferenceException in OwinHttpListener.cs on .Net(Core) 5

I am porting a .NET Framework 4.7 application to .NET 5 which uses Microsoft.AspNet.WebApi.OwinSelfHost 5.2.7 (which depends on Microsoft.Owin.Host.HttpListener).

When running my app in VisualStudio I can see NullReferenceExceptions logged in DEBUG outputs. When using decompile feature I can see the source from accessing the 2 static fields:

https://github.com/aspnet/AspNetKatana/blob/1fba52940ccfa74470c75c627699baca13aadfa4/src/Microsoft.Owin.Host.HttpListener/OwinHttpListener.cs#L30-L31

They depend on reflection of non-public fields.

The NRE itself happens at line 226 when accessing text = (((string)CookedPathField.GetValue(request)) ?? string.Empty);. For mono there seems to be another approach used.

Can you please review the reflection based access to the 2 fields using .NET 5?

[Tratcher]

Unlike ASP.NET 4.x, ASP.NET Core fully supports self-host scenarios. Much of ASP.NET Core was derived from these Microsoft.Owin libraries.

This: https://github.com/MediaPortal/MediaPortal-2/blob/8234fb872b2f1b59338468cbd57d2127edff0388/MediaPortal/Source/Core/UPnP/Infrastructure/Dv/UPnPServer.cs#L185

Becomes something like: https://github.com/dotnet/aspnetcore/blob/b143a974a5574b9fccedbbe2389aabbfd48fdb6f/src/Hosting/samples/GenericWebHost/Program.cs#L14-L28 but change RunAsync to StartAsync since it looks like you want to start multiple servers.

[morpheusxx]

https://github.com/aspnet/AspNetKatana/blob/1fba52940ccfa74470c75c627699baca13aadfa4/src/Microsoft.Owin.Host.HttpListener/OwinHttpListener.cs#L289 I changed this code line to: if (IsMono || CookedPathField == null) and it fixed my issue. I didn’t find other issues yet.