C#:异步NamedPipeServerStream管道正在关闭异常

Question

我之前关于同一主题的问题:C#:异步NamedPipeServerStream理解 现在我有下一个:

private void StartListeningPipes()
{
    try
    {
        isPipeWorking = true;
                namedPipeServerStream = new NamedPipeServerStream(PIPENAME, PipeDirection.InOut, 1, PipeTransmissionMode.Byte, PipeOptions.Asynchronous, BUFFERSIZE, BUFFERSIZE);
                Console.Write("Waiting for client connection...");
                while(isPipeWorking)
                {
            IAsyncResult asyncResult = namedPipeServerStream.BeginWaitForConnection(this.WaitForConnectionAsyncCallback, null);
                        Thread.Sleep(3*1000);
                }
        }
        //// Catch the IOException that is raised if the pipe is broken or disconnected.
        catch (IOException e)
        {
        Console.WriteLine("IOException: {0}. Restart pipe server...", e.Message);
                StopListeningPipes();
                StartListeningPipes();
        }
        //// Catch ObjectDisposedException if server was stopped. Then do nothing.
        catch (ObjectDisposedException)
        {
        }
}

private void WaitForConnectionAsyncCallback(IAsyncResult result)
{
    try
    {
        namedPipeServerStream.EndWaitForConnection(result);
        Console.WriteLine("Client connected.");
        namedPipeServerStream.WaitForPipeDrain();
                byte[] buff = new byte[BUFFERSIZE];
                namedPipeServerStream.Read(buff, 0, BUFFERSIZE);
                string recStr = TrimNulls(buff);
                Array.Clear(buff, 0, buff.Length);
                Console.WriteLine();
                Console.WriteLine("'"+recStr+"'");
    }
    catch (Exception e)
    {
        Console.WriteLine("Error: " + e.Message);            
        }
}

但我得到了

The pipe is being closed Exception 每次我收到客户的消息

为什么？

我的客户:

 using (NamedPipeClientStream pipeStream = new NamedPipeClientStream(General.PIPENAME))
{
    try
        {
        byte[] bytes = General.Iso88591Encoding.GetBytes(sendingMessage);
                pipeStream.Write(bytes, 0, bytes.Length);
                pipeStream.Flush();
                pipeStream.WaitForPipeDrain();
        }
        catch (TimeoutException)
        {
        Console.WriteLine("Timeout error!");
        }
    catch (Exception e)
        {
        Console.WriteLine(string.Format("Error! ", e.Message));
        }
}

---

目前的最终代码是:

/// <summary>
        /// Create new NamedPipeServerStream for listening to pipe client connection
        /// </summary>
        private void ListenForPipeClients()
        {
            if (!this.isListeningToClients)
                return;

            try
            {
                PipeSecurity ps = new PipeSecurity();
                PipeAccessRule par = new PipeAccessRule("Everyone", PipeAccessRights.ReadWrite, System.Security.AccessControl.AccessControlType.Allow);
                ps.AddAccessRule(par);
                pipeClientConnection = new NamedPipeServerStream(General.PIPENAME, PipeDirection.InOut, 1, PipeTransmissionMode.Byte, PipeOptions.Asynchronous, General.BUFFERSIZE, General.BUFFERSIZE, ps);
                Console.Write("Waiting for client connection...");
                /*namedPipeServerStream.WaitForConnection();
                OnPipeConnected(namedPipeServerStream);*/
                IAsyncResult result = pipeClientConnection.BeginWaitForConnection(OnPipeConnected, pipeClientConnection);
            }
            catch (ObjectDisposedException)
            {
                //// Catch ObjectDisposedException if server was stopped. Then do nothing.
            }
            catch (Exception e)
            {
                Console.WriteLine("Error occures: {0}. Restart pipe server...", e.Message);
                this.logger.Add(LogLevel.Warning, string.Format("Error occures: {0}. Restart pipe server...", e.Message));
                ListenForPipeClients();
            }
        }

        /// <summary>
        /// Async callback on client connected action
        /// </summary>
        /// <param name="asyncResult">Async result</param>
        private void OnPipeConnected(IAsyncResult asyncResult)
        {
            using (var conn = (NamedPipeServerStream)asyncResult.AsyncState)
            {
                try
                {
                    conn.EndWaitForConnection(asyncResult);
                    Console.WriteLine("Client connected.");
                    PipeClientConnection clientConnection = new PipeClientConnection(conn, notifierSenderCache, defaultStorageTime);
                }
                catch (Exception e)
                {
                    Console.WriteLine(e.Message);
                    this.logger.Add(LogLevel.Warning, e.Message);
                }
            }

            ListenForPipeClients();
        }

Answer 1

您似乎需要NamedPipeServerStream为每个客户单独分配.(请注意,我不是那个发现它的人,请参阅其他答案.)我认为工作服务器端看起来像这样(草稿代码):

while(this.isServerRunning)
{
     var pipeClientConnection = new NamedPipeServerStream(...);

     try
     {
         pipeClientConnection.WaitForConnection();
     }
     catch(...)
     {
         ...
         continue;
     }

     ThreadPool.QueueUserWorkItem(state =>
          {
               // we need a separate variable here, so as not to make the lambda capture the pipeClientConnection variable, which is not recommended in multi-threaded scenarios
               using(var pipeClientConn = (NamedPipeServerStream)state)
               {
                    // do stuff
                    ...
               }
          }, pipeClientConnection);
}

作为旁注,正如在你的问题的评论中指出的那样,你浪费内存通过BeginWaitForConnection循环调用每隔3秒启动一次新的异步调用(唯一不会浪费内存的情况是新的连接的间隔时间小于3秒,但我怀疑你是否可以确定这一点.您可以看到,无论最后一个是否仍处于待处理状态或已完成,您基本上每3秒钟就会启动一次新的异步调用.此外,它 - 再次 - 没有考虑到NamedPipeServerStream每个客户需要一个单独的.

要解决此问题,您需要消除循环,并使用回调方法"链接"BeginWaitForConnection调用.这是一种类似的模式,在使用.NET时,您会经常在异步I/O中看到这种模式.代码草案:

private void StartListeningPipes()
{
    if(!this.isServerRunning)
    {
        return;
    }

    var pipeClientConnection = new NamedPipeServerStream(...);

    try
    {
        pipeClientConnection.BeginWaitForConnection(asyncResult =>
            {
                // note that the body of the lambda is not part of the outer try... catch block!
                using(var conn = (NamedPipeServerStream)asyncResult.AsyncState)
                {
                    try
                    {
                        conn.EndWaitForConnection(asyncResult);
                    }
                    catch(...)
                    {
                        ...
                    }

                    // we have a connection established, time to wait for new ones while this thread does its business with the client
                    // this may look like a recursive call, but it is not: remember, we're in a lambda expression
                    // if this bothers you, just export the lambda into a named private method, like you did in your question
                    StartListeningPipes();

                    // do business with the client
                    conn.WaitForPipeDrain();
                    ...
                }
            }, pipeClientConnection);
    }
    catch(...)
    {
        ...
    }
}

控制流程将是这样的:

• [主线程] StartListeningPipes():创建NamedPipeServerStream,启动BeginWaitForConnection()
• [threadpool thread 1] client#1 connected,BeginWaitForConnection()callback:EndWaitForConnection()then StartListeningPipes()
• [threadpool thread 1] StartListeningPipes():创建新的NamedPipeServerStream,BeginWaitForConnection()调用
• [threadpool thread 1]回到BeginWaitForConnection()回调:与连接的客户端开始业务(#1)
• [threadpool thread 2]客户端#2连接,BeginWaitForConnection()回调:...
• ...

我认为这比使用阻塞I/O困难得多 - 事实上,我不太确定我做对了,如果你看到任何错误请指出 - 而且它也更加令人困惑.

要在任一示例中暂停服务器,您显然会将this.isServerRunning标志设置为false.