示例命名管道具有读/写超时的IPC

Question

我正在努力寻找实现具有强大超时管理的命名管道IPC的最佳方法.我并不是指建立连接时超时,而是读/写流超时.

我发现的所有示例都没有超时实现.

有人可以给我一个工作实例和/或指向一个显示这个的例子吗？

Answer 1

NamedPipeClientStream.BeginRead您可能需要做的是使用and进行异步读写NamedPipeClientStream.BeginWrite；然后将使用计时器来检测何时一段时间内没有发送或接收数据。

每当发送或接收数据时，DateTime都会将一个字段设置为DateTime.Now，并且每次执行计时器都会检查该字段以确定是否发生超时。如果发生这种情况，NamedPipeClientStream可以关闭 ，并且可以捕获NamedPipeClientStream.EndRead和中的异常。NamedPipeClientStream.EndWrite

我还没有准备好一个工作示例，但如果您需要的话，我会开始编写一个。希望这能同时帮助您。

这是一些非常粗糙的示例代码。还需要做更多的事情，例如实现IDisposable和添加写入方法。不过，这应该有助于说明这个想法。最好使用此代码作为模型，而不是直接使用它。我已经测试了代码，看看它是否可读。

//this is a very rough model of how to do it. a lot more would need to be implemented
//i'm assuming you plan to continuously read from it. i can think up another example if you're not
//also not thread safe
public class MyPipeClient
{
    NamedPipeClientStream PipeClient = new NamedPipeClientStream("testpipe1");
    Timer TimeoutTimer;
    DateTime LastRead;
    const int TimeoutSeconds = 120; //2 mins

    //will connect and start receiving
    public void Connect()
    {
        PipeClient.Connect();
        LastRead = DateTime.Now;

        TimeoutTimer = new Timer(TimeoutCheck, this, 0, 1000); //check every second

        Read(this);
    }

    public void Disconnect()
    {
        PipeClient.Close(); PipeClient = null;
        TimeoutTimer.Dispose(); TimeoutTimer = null;
    }

    static void Read(MyPipeClient client)
    {
        PipeState state = new PipeState(client);

        try
        {
            client.PipeClient.BeginRead(state.Buffer, 0, state.Buffer.Length, ReadCallback, state);
        }
        catch (InvalidOperationException) //disconnected/disposed
        {
            return;
        }
    }

    static void ReadCallback(IAsyncResult ar)
    {
        PipeState state = (PipeState)ar.AsyncState;
        MyPipeClient client = state.Client;

        client.LastRead = DateTime.Now;

        int bytesRead;

        try
        {
            bytesRead = client.PipeClient.EndRead(ar);
        }
        catch (IOException) //closed
        {
            return;
        }

        if (bytesRead > 0)
        {
            byte[] data = state.Buffer;

            //TODO: something
        }
        else //i've never used pipes, so i'm assuming this behavior exists with them
        {
            client.Disconnect();
            return;
        }

        Read(client);
    }

    static void TimeoutCheck(object state)
    {
        MyPipeClient client = (MyPipeClient)state;

        TimeSpan timeSinceLastRead = DateTime.Now - client.LastRead;

        if (timeSinceLastRead.TotalSeconds > TimeoutSeconds)
        {
            client.Disconnect();
        }
    }
}

class PipeState
{
    public byte[] Buffer = new byte[4096];
    public MyPipeClient Client;

    public PipeState(MyPipeClient client)
    {
        Client = client;
    }
}