.net – 处理Microsoft.Owin.Hosting.WebApp会抛出’System.ObjectDisposedException’

public void Start()
    {
        myWebApp = WebApp.Start<MyApp>(url);
    }

    private void dispose(bool isdisposing)
    {
        if (disposed) return;

        if (isdisposing)
            myWebApp.dispose();

        disposed = true;
    }

在探索了Katana源代码之后,我发现了这个问题的原因.它是Microsoft.Owin.Host.HttpListener.OwinHttpListener.ProcessRequestsAsync()方法.它启动while循环,包含在try-catch部分中的私有HttpListener实例的_listener.GetContextAsync()调用.

类也实现了Idisposable并包含dispose()方法.此方法处理私有HttpListener实例.

当你调用WebApp.Start()时,它返回一个Idisposable实例,它只有dispose()方法,它处理OwinHttpListener.

因此,当你处理它时,你调用它的OwinHttpListener的dispose()方法,它处理私有的HttpListener.

但同时ProcessRequestsAsync()调用_listener.GetContextAsync(),但_listener已经处理并抛出ObjectdisposedException. catch块记录异常并从ProcessRequestsAsync()返回.

我认为,ProcessRequestsAsync()中的双重检查锁可能是一个不错的选择.

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();
}