Websocket hangs on certain proxies

[ste-art]

Websocket can hang if used with some proxies.
After calling WebSocket.Open no events (OnWsClosed, OnWsOpened, OnWsError) are raised and some internal thread starts to generate high CPU usage.

More info: ProxyConnectorBase.AsyncEventArgsCompleted receives an empty buffer - SocketAsyncEventArgs.Buffer is filled with zeros, Offset and BytesTransferred are 0. It calls HttpConnectProxy.ProcessReceive where e.Buffer.SearchMark returns -1 and executes this code:

            if (result < 0)
            {
                int total = e.Offset + e.BytesTransferred;

                if(total >= m_ReceiveBufferSize)
                {
                    OnException("receive buffer size has been exceeded");
                    return;
                }

                e.SetBuffer(total, m_ReceiveBufferSize - total);
                StartReceive(context.Socket, e);
                return;
            }

total becomes 0 too, then StartReceive is called, that raises ProxyConnectorBase.AsyncEventArgsCompleted with empty buffer again and this loop continues infinitely.

I suggest a fix:

                if (e.BytesTransferred == 0)
                {
                    OnException("receive buffer is empty");
                    return;
                }

But I'm not sure could BytesTransferred be zero in other healthy TCP connections.

Proxies to debug the issue with (there are plenty of them in varios online free proxies lists): 111.13.136.46:80 139.162.182.113:80 202.43.147.226:1080

[kerryjiang]

The situation "e.BytesTransferred == 0" means the connection was closed.

[bogdandanielb]

I'm experiencing the same CPU intensive processing threads left behind on non-working proxies even though the WebSocket is properly disposed. Was this issue addressed in the latest release?

Thanks, Daniel