Disposing Microsoft.Owin.Hosting.WebApp throws 'System.ObjectDisposedException'

After exploring the Katana source code, I found a reason for this problem. It is the Microsoft.Owin.Host.HttpListener.OwinHttpListener.ProcessRequestsAsync() method. It starts while-loop containing _listener.GetContextAsync() call of a private HttpListener instance in try-catch section.

Also class implements IDisposable and contains a Dispose() method. This method disposes the private HttpListener instance.

When you call WebApp.Start() it returns an instance of IDisposable, that only has Dispose() method, that disposes OwinHttpListener.

So, when you dispose it, you call its Dispose() method of OwinHttpListener, which disposes the private HttpListener.

But at the same time ProcessRequestsAsync() calls _listener.GetContextAsync(), but _listener is already disposed and throws ObjectDisposedException. catch block log the exception and returns from ProcessRequestsAsync().

I think, that double check lock in ProcessRequestsAsync() may be a good option.

private async void ProcessRequestsAsync(){    while (_listener.IsListening && CanAcceptMoreRequests)    {        Interlocked.Increment(ref _currentOutstandingAccepts);        HttpListenerContext context;        try        {            context = await _listener.GetContextAsync();        }        (SOME_OTHER_CATCHES)        catch (ObjectDisposedException ode)        {            // These happen if HttpListener has been disposed            Interlocked.Decrement(ref _currentOutstandingAccepts);            LogHelper.LogException(_logger, "Accept", ode);            return;        }        (SOME_OTHER_CODE)    }}public void Dispose(){    if (_listener.IsListening)    {        _listener.Stop();    }    ((IDisposable)_listener).Dispose();}