Periodically getting this exception about nowin

[Bobris]

It should never happen ... Can you create simple repro? Or you can enable detailed logging ...
What version of Nowin, what framework, OS version?

[SHWotever]

Hi ! I reproduce it using nowin + nancyFx, I think it happens when chrome aborts requests. (I only reproduce it when loading it pressing f5 like a mad)

Hi - nowin 0.19.0, .net 4.5, windows 7 Pro SP1

The following is a test that reproduces quickly (within the first or second run).

using System;
using System.Text;
using System.Net.Sockets;
using System.Net;

namespace NowinCancelTest
{
class Program
{
static void Main(string[] args)
{
byte[] bytes = Encoding.ASCII.GetBytes(string.Format("OPTIONS /api/v1/sessions/1/ixnetwork/topology/deviceGroup/ethernet/dhcp4client HTTP/1.1{0}Connection: keepalive{1}Cache-Control: no-cache{2}{3}",
Environment.NewLine,
Environment.NewLine,
Environment.NewLine,
Environment.NewLine));

        for (int i = 0; i < 10; i++)
            Request(bytes, false);

        for (int i = 0; i < 2; i++)
            Request(bytes, true);

        for (int i = 0; i < 20; i++)
            Request(bytes, false);

        for (int i = 0; i < 2; i++)
            Request(bytes, true);
    }

    static void Request(byte[] bytes, bool receive)
    { 
        try
        {
            Socket socket = new Socket(SocketType.Stream, ProtocolType.Tcp);
            socket.Connect(IPAddress.Loopback, 12345);

            if (receive)
            {
                socket.Send(bytes);
                byte[] recvBytes = new byte[32767];
                int count = socket.Receive(recvBytes);
                System.Diagnostics.Debug.WriteLine(Encoding.ASCII.GetString(recvBytes, 0, count));
            }
            else
            {
                socket.BeginSend(bytes, 0, bytes.Length, SocketFlags.None, null, null);
            }

            socket.Shutdown(SocketShutdown.Both);
            socket.Close();
            socket = null;
        }
        catch(Exception e)
        {
            System.Diagnostics.Debug.WriteLine(e.ToString());
        }
    }
}

}

[Bobris]

Thanks for repro, will try to investigate tomorrow...

[adamburgess]

Also happening for me (I'm using Heroku, running on the latest mono release)

2015-11-03T02:13:11.148046+00:00 heroku[router]: at=info method=POST path="/" host=blender-cycles-sharing.herokuapp.com request_id=eda1a912-9e12-4e78-9855-e4764fb2929d fwd="54.235.201.241" dyno=web.1 connect=1ms service=112ms status=200 bytes=164
2015-11-03T02:13:11.159933+00:00 app[web.1]:
2015-11-03T02:13:11.159937+00:00 app[web.1]: Unhandled Exception:
2015-11-03T02:13:11.159939+00:00 app[web.1]: System.InvalidOperationException: Already receiving or accepting
2015-11-03T02:13:11.159940+00:00 app[web.1]:   at Nowin.SaeaLayerCallback.StartAccept (System.Byte[] buffer, Int32 offset, Int32 length) <0x4175b8c0 + 0x00189> in <filename unknown>:0
2015-11-03T02:13:11.159941+00:00 app[web.1]:   at Nowin.Transport2HttpHandler.RealPrepareAccept () <0x4175b870 + 0x0003d> in <filename unknown>:0
2015-11-03T02:13:11.159941+00:00 app[web.1]:   at Nowin.Transport2HttpHandler.PrepareAccept () <0x4175b6b0 + 0x00064> in <filename unknown>:0
2015-11-03T02:13:11.159942+00:00 app[web.1]:   at Nowin.SaeaLayerCallback.ProcessDisconnect () <0x41762480 + 0x00138> in <filename unknown>:0
2015-11-03T02:13:11.159943+00:00 app[web.1]:   at Nowin.SaeaLayerCallback.IoCompleted (System.Object sender, System.Net.Sockets.SocketAsyncEventArgs e) <0x4175e940 + 0x000ec> in <filename unknown>:0
2015-11-03T02:13:11.159948+00:00 app[web.1]:   at System.Net.Sockets.SocketAsyncEventArgs.OnCompleted (System.Net.Sockets.SocketAsyncEventArgs e) <0x4175e900 + 0x0002e> in <filename unknown>:0
2015-11-03T02:13:11.159949+00:00 app[web.1]:   at System.Net.Sockets.SocketAsyncEventArgs.Complete () <0x4175e8e0 + 0x00013> in <filename unknown>:0
2015-11-03T02:13:11.159949+00:00 app[web.1]:   at System.Net.Sockets.Socket.<DisconnectAsyncCallback>m__5 (IAsyncResult ares) <0x41762150 + 0x001ee> in <filename unknown>:0
2015-11-03T02:13:11.159961+00:00 app[web.1]:   at System.Net.Sockets.SocketAsyncResult+<Complete>c__AnonStorey0.<>m__0 (System.Object _) <0x416d8620 + 0x0001d> in <filename unknown>:0
2015-11-03T02:13:11.159961+00:00 app[web.1]:   at System.Threading.QueueUserWorkItemCallback.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem () <0x7f88da099eb0 + 0x0002f> in <filename unknown>:0
2015-11-03T02:13:11.159962+00:00 app[web.1]:   at System.Threading.ThreadPoolWorkQueue.Dispatch () <0x7f88da098460 + 0x001d6> in <filename unknown>:0
2015-11-03T02:13:11.159963+00:00 app[web.1]:   at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback () <0x7f88da099d30 + 0x00008> in <filename unknown>:0
2015-11-03T02:13:11.943222+00:00 heroku[web.1]: Process exited with status 255
2015-11-03T02:13:11.955972+00:00 heroku[web.1]: State changed from up to crashed

[Bobris]

I can reproduce it and working on fix ... It is very complex to synchronize all these async operations happening in parallel in multiple threads... Actually I have code which does not show problem, but it regressed one test (only in release, not in debug :-( )

[Bobris]

Published in nuget as 0.20.0. I cannot reproduce problem anymore even after 10 minutes of run of provided test. Also all tests passing repeatedly without problems.