Restart application gives HttpSysException The prefix is already registered

[rgroenewoudt]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

I would like to start and stop our application on demand, without exiting the process. Code would be similar like:

 var builder = WebApplication.CreateBuilder(args);

 builder.WebHost.UseHttpSys();
 builder.Services.AddControllers();

 var app = builder.Build();

 await app.StartAsync();
 await app.StopAsync();

// Something here

 await app.StartAsync();

However, with http.sys this gives an exception: Microsoft.AspNetCore.Server.HttpSys.HttpSysException: 'The prefix 'http://localhost:5074/' is already registered.'.

Minimum testcase: WebApplication2.zip

Is there any way to restart the app or a workaround to make this work?

Expected Behavior

No response

Steps To Reproduce

No response

Exceptions (if any)

No response

.NET Version

9.0.102

Anything else?

No response

[rgroenewoudt]

HttpSysListener registers the url prefixes on start.

HttpSysListener.Start() is called in MessagePump.StartAsync() but HttpSysListener.Stop() is not called in MessagePump.StopAsync(). The url prefixes are not unregistered when stopping the application, only when disposed.

[rgroenewoudt]

A workaround is to add after app.StopAsync():

var httpSysListener = instance.GetType().GetProperty("Listener", BindingFlags.NonPublic | BindingFlags.Instance)!.GetValue(instance)!;
httpSysListener.GetType().GetMethod("Stop", BindingFlags.NonPublic | BindingFlags.Instance)!.Invoke(httpSysListener, null);