C＃在沒有busyTimes的情況下在tcp網絡中偵聽？

Question

我正試圖捕獲特定端口上的所有傳入事件。它工作正常，但我認爲，我的Socket被阻塞5秒，而stream.Read()正在執行。 stream.Read()忙時，如果有包裹進入，會發生什麼情況？我怎麼能避免可能的數據丟失？

public static void Main(string[] args) 
    { 

     System.Console.WriteLine("Testprogramm Connection\n"); 
     //ThreadListener tl = new ThreadListener(); 
     DateTime startTime3 = DateTime.Now; 
     DateTime startTime4 = DateTime.Now; 

     TimeSpan duration3; 
     TimeSpan duration4; 

     while (true) 
     { 
      DataPackage dp = Connection.readEvent(4002, 3000); 

      DateTime EndZeit = DateTime.Now; 
      if (dp.Ip.Equals("192.168.101.3")) 
      { 
       duration3 = EndZeit - startTime3; 
       System.Console.WriteLine("Duration to last receive: " + duration3); 
       startTime3 = DateTime.Now; 
      } 
      if (dp.Ip.Equals("192.168.101.4")) 
      { 
       duration4 = EndZeit - startTime4; 
       System.Console.WriteLine("Duration to last receive: " + duration4); 
       startTime4 = DateTime.Now; 
      } 
      System.Console.WriteLine(); 
     } 
    } 

    ...Connection.cs 
    public static DataPackage readEvent(int port, int size) 
    { 
     DataPackage dp = new DataPackage(); 
     byte[] bytes = new byte[size]; 
     String ip_client = ""; 
     IPHostEntry ipHostInfo = Dns.GetHostEntry(Dns.GetHostName()); 
     IPAddress ipAddress = ipHostInfo.AddressList[1]; 
     try 
     { 
      System.Console.Write("Wait...:"); 
      listener = new TcpListener(ipAddress, port); 
      listener.Start(); 
      tcpClient = listener.AcceptTcpClient(); 
      tcpClient.NoDelay = true; 
      tcpClient.Client.NoDelay = true; 

      ip_client = tcpClient.Client.RemoteEndPoint.ToString(); 

      stream = tcpClient.GetStream(); 
      DateTime startTime = DateTime.Now; 
      stream.Read(bytes, 0, bytes.Length); 
      DateTime endTime = DateTime.Now; 

      stream.Close(); 
      tcpClient.Close(); 
      listener.Stop(); 
      dp.Data = bytes; 
      dp.setIP(ip_client); 

      System.Console.Write("...received from " + ip_client + " busy:"); 
      TimeSpan duration = endTime - startTime; 
      System.Console.WriteLine(duration.Seconds + "s"); 
     } 
     catch (Exception e) 
     { 
      Console.WriteLine(e.Message); 
      closeAllConnections(); 
      return null; 
     } 
     return dp; 
    } 

Answer 1

我並不感到驚訝，你看到事件間的延遲。在您的readEvent方法中，您正在創建套接字，然後偵聽傳入連接，然後執行read（），然後關閉所有套接字。需要一點時間來設置您的套接字。如果您創建連接類的套接字成員，執行初始化（創建，偵聽和連接），然後在readEvent方法中檢索消息，那麼這是更好的方法。更奇特的做法可能是排隊所有的事件，以便您的連接的客戶端可以去拿起它們，但這涉及到一些異步編程。

 public class Connection : IDisposable { 
    private readonly Queue<DataPackage> messages = new Queue<DataPackage>(); 

    public object syncLock = new Object(); 
    public List<DataPackage> GetCurrentMessages() { 
     Monitor.Enter(syncLock); 
     var result = new List<DataPackage>(); 
     try { 
      foreach (var item in messages) { 
       result.Add(item); 
      } 
      messages.Clear(); 
     } finally { 
      Monitor.Exit(syncLock); 
     } 
     return result; 
    } 

    private TcpListener listener; 
    private TcpClient tcpClient; 
    private int bufferSize; 
    private bool running; 
    public void Init(int port, int size) { 
     // not real thread safe here 
     if (running) return; 
     running = true; 
     bufferSize = size; 
     IPHostEntry ipHostInfo = Dns.GetHostEntry(Dns.GetHostName()); 
     IPAddress ipAddress = ipHostInfo.AddressList[1]; 
     listener = new TcpListener(ipAddress, port); 
     listener.Start(); 
     listener.BeginAcceptSocket(ar => { 
      tcpClient = listener.AcceptTcpClient(); 
      tcpClient.NoDelay = true; 
      listener.EndAcceptTcpClient(ar); 
      var t = new Thread(readEvent); 
      t.Start(); 
     }, null); 
    } 

    private bool shouldRead = true; 
    private void readEvent() { 

     while (shouldRead) { 
      byte[] bytes = new byte[bufferSize]; 

      try { 
       Console.Write("Wait...:"); 

       var ip_client = tcpClient.Client.RemoteEndPoint.ToString(); 

       var stream = tcpClient.GetStream(); 
       DateTime startTime = DateTime.Now; 
       stream.Read(bytes, 0, bytes.Length); 
       DateTime endTime = DateTime.Now; 
       var package = new DataPackage(); // add your stuff in here 

       Monitor.Enter(syncLock); 
       try { 
        messages.Enqueue(package); 
       } finally { 
        Monitor.Exit(syncLock); 
       } 

       System.Console.Write("...received from " + ip_client + " busy:"); 
       TimeSpan duration = endTime - startTime; 
       System.Console.WriteLine(duration.Seconds + "s"); 
      } catch (Exception e) { 
       Console.WriteLine(e.Message); 
      } 
     } 

    } 

    public class DataPackage {} 

    #region IDisposable Members 
    private bool disposed; 
    void Dispose(bool disposing) { 
     if (!disposed) { 
      if (disposing) { 
       shouldRead = false; 
       tcpClient.Close(); 
       listener.Stop(); 
      } 
      //Clean up unmanaged resources 
     } 
     disposed = true; 
    } 
    public void Dispose() { 
     Dispose(true); 
    } 
    #endregion 
} 

Answer 2

你的TCP監聽器可能正在等待緩衝區填滿。

• 減小緩衝區大小;
• 用PUSH bit集發送數據包;或
• 您的客戶正在等待建立一個重要的數據包大小。

要設置緩衝區大小，請使用TcpClient.ReceiveBufferSize屬性。

爲了避免拖延而等待緩衝區填滿時，TcpClient.NoDelay屬性設置爲true。

Answer 3

使用TcpClient.Available查看是否有足夠的字節可供讀取。

http://msdn.microsoft.com/en-us/library/system.net.sockets.tcpclient.available%28v=vs.110%29.aspx

Answer 4

我估計沒有任何數據丟失。在你的大小寫塊線程中使用Read方法，直到第一筆數據量到來（甚至1字節）。理論上，如果客戶會保持「沉默」，您可以等待無限的時間。如果你想限制的等待時間，使用tcpClient.ReceiveTimeout，像這樣：

tcpClient.ReceiveTimeout = 3000; 

於是，就有了一切完全正確的代碼，問題是客戶保持沉默5秒。

PS：你爲什麼不使用IPAddress.Any？在某些情況下，此Dns.GetHostEntry(Dns.GetHostName())可能需要很長時間。

var listener = new TcpListener(IPAddress.Any, port);