Re: problem with Socket.Available

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Droopy <droopytoonnospam@xxxxxxxxxxx> wrote in
news:Xns96BCB21CFAA95droopytoonnospamhotm@xxxxxxxxxxxxxx:

> OK no help here ;-(
>
> I removed all calls to "Available".
> I wonder now if I should call "Poll" ?
> I mean for better performance.

I forgot to mention that I am sending a lot (about 50/sec) of short
(average 16 bytes, up to 256 bytes) messages.

Who can help me ?

> I used both "Available" and "Poll" to prevent blocking calls to
> "Receive" but as I am using separate threads ...
>
> What is best ?
>
> Thanks in advance for your help
>
> Droopy <droopytoonnospam@xxxxxxxxxxx> wrote in
> news:Xns96BBA9F069261droopytoonnospamhotm@xxxxxxxxxxxxxx:
>
>> Hi,
>>
>> I try to implement a reusable socket class to send and receive data.
>> It seems to work but I have 2 problems :
>>
>> 1) I rely on Socket.Available to detect that the connection is closed
>> (no more data to expect). Sometimes, Socket.Available returns 0 but
>> the other end of the connection did not close it !
>>
>> 2) This class will be used by many other classes so I have to use the
>> minimum system resource. I just found that the first parameter for
>> Socket.Poll is in microseconds ! I thought it was milliseconds.
>>
>> How can I improve/correct this class ?
>>
>> Thanks in advance.
>>
>>
>> Here below, you will find the code for this class (TcpHelper).
>> It is used as following :
>>
>> TcpHelper transport = new TcpHelper;
>> transport.OnConnectionFailed += new EventHandler (...);
>> transport.CallbackReceivedData += new EventHandler (...);
>>
>> transport.Open (existingSocket, caller);
>> or
>> transport.Open (hostname, port);
>>
>> transport.StartReading ();
>>
>>
>> the code :
>>
>>
>> using System;
>> using System.Net;
>> using System.Net.Sockets;
>> using System.Threading;
>>
>> namespace IprRouting
>> {
>> public class TcpEventData : System.EventArgs
>> {
>> private byte [] _header;
>> private byte [] _data;
>>
>> public TcpEventData (byte [] header, byte [] data)
>> {
>> _header = header;
>> _data = data;
>> }
>>
>> public byte [] Header
>> {
>> get { return _header; }
>> }
>>
>> public byte [] Data
>> {
>> get { return _data; }
>> }
>> }
>>
>> public class TcpHelper
>> {
>> private Socket _socket = null;
>> private bool _mustRun = true;
>> private string _hostName = string.Empty;
>> private IPAddress _ipAddress = IPAddress.IPv6None;
>> private string _caller = string.Empty;
>>
>> private const int PollTimeout = 100;
>>
>> public event EventHandler CallbackReceivedData;
>> public event EventHandler OnConnectionFailed;
>>
>> private static string localHostname = string.Empty;
>> private static IPAddress [] localIpAddresses = null;
>>
>> public TcpHelper ()
>> {
>> }
>>
>> #region Properties
>>
>> public string HostName
>> {
>> get { return _hostName; }
>> }
>>
>> public IPAddress IPAddress
>> {
>> get { return _ipAddress; }
>> }
>>
>> public string RemoteEndPoint
>> {
>> get
>> {
>> if (_socket == null)
>> return "Not connected";
>> else
>> {
>> if (! _socket.Connected)
>> return "Not connected";
>> else
>> return _socket.RemoteEndPoint.ToString
>> ();
>> }
>> }
>> }
>>
>> #endregion // Properties
>>
>> // remove domain part in host name (i.e. in "xxx.yyy.zzz",
>> // remove ".yyy.zzz"
>> private string StandardizeHostname (string hostname)
>> {
>> int dotIndex = hostname.IndexOf ('.');
>>
>> if (dotIndex != -1)
>> {
>> return hostname.Substring (0, dotIndex).ToUpper
>> ();
>> }
>> else
>> return hostname;
>> }
>>
>> public void StartReading ()
>> {
>> Thread handleTcp = new Thread (new ThreadStart
>> (ReadTcp));
>>
>> if (_caller.Length > 0)
>> {
>> if (_hostName.Equals ("localhost"))
>> handleTcp.Name = "TcpHelper " + _caller;
>> else
>> handleTcp.Name = String.Format ("TcpHelper
>> {0}
>> {1}", _caller, _hostName);
>> }
>> else
>> handleTcp.Name = String.Format ("TcpHelper {0}",
>> _hostName);
>>
>> if (Log.Current.IsInfoEnabled)
>> Log.Current.Info ("TcpHelper::StartReading " +
>> handleTcp.Name);
>>
>> handleTcp.Priority = ThreadPriority.Normal;
>> handleTcp.IsBackground = true; // thread will be
>> closed
>> when application exits
>> handleTcp.Start ();
>> }
>>
>> private void CloseIfActive ()
>> {
>> if (_socket != null)
>> {
>> if (Log.Current.IsErrorEnabled)
>> Log.Current.Error ("TcpHelper::CloseIfActive
>> closing existing socket " +
>> RemoteEndPoint);
>> Close (false);
>> }
>> }
>>
>> public void Open (Socket socket, string caller)
>> {
>> IPEndPoint ipEndPoint = (IPEndPoint)
>> socket.RemoteEndPoint;
>> _ipAddress = ipEndPoint.Address;
>>
>> IPHostEntry hostInfo = TcpHelper.GetHostByAddress
>> (_ipAddress);
>> if (hostInfo != null)
>> _hostName = StandardizeHostname
>> (hostInfo.HostName);
>> else
>> _hostName = _ipAddress.ToString ();
>>
>> _caller = caller;
>>
>> CloseIfActive ();
>>
>> _socket = socket;
>> }
>>
>> public short Open (string hostName, int port)
>> {
>> short returnCode = 0;
>>
>> _hostName = hostName;
>>
>> returnCode = Open (port);
>>
>> return returnCode;
>> }
>>
>> private short Open (int port)
>> {
>> if (Log.Current.IsInfoEnabled)
>> Log.Current.Info ("TcpHelper::Open open " +
>> _hostName);
>>
>> if (_hostName.Length <= 0)
>> {
>> if (Log.Current.IsErrorEnabled)
>> Log.Current.Error ("TcpHelper::Open invalid
>> host name " + _hostName);
>> return 4;
>> }
>>
>> CloseIfActive ();
>>
>> IPHostEntry hostInfo = TcpHelper.GetHostInfo
>> (_hostName);
>>
>> if (hostInfo == null)
>> {
>> if (Log.Current.IsErrorEnabled)
>> Log.Current.Error ("TcpHelper::Open cannot
>> get
>> host info " + _hostName);
>> return 5;
>> }
>> else
>> {
>> _hostName = StandardizeHostname
>> (hostInfo.HostName);
>> _ipAddress = hostInfo.AddressList [0];
>> }
>>
>> if (TcpHelper.IsLocalHost (hostInfo.AddressList))
>> {
>> if (Log.Current.IsInfoEnabled)
>> Log.Current.Info ("TcpHelper::Open skip local
>> host " + _hostName);
>> return 6;
>> }
>>
>> if (Log.Current.IsInfoEnabled)
>> Log.Current.Info ("TcpHelper::Open opening " +
>> _hostName +
>> ", IP address " + _ipAddress + " port #" +
>> port.ToString ());
>>
>> IPEndPoint endPoint = new IPEndPoint (_ipAddress,
>> port); _socket = new Socket
>> (AddressFamily.InterNetwork,
>> SocketType.Stream, ProtocolType.Tcp);
>> _socket.SetSocketOption (SocketOptionLevel.Socket,
>> SocketOptionName.SendTimeout, TcpServer.TcpSendTimeout);
>> _socket.SetSocketOption (SocketOptionLevel.Socket,
>> SocketOptionName.ReceiveTimeout, TcpServer.TcpReceiveTimeout);
>> _socket.SetSocketOption (SocketOptionLevel.Socket,
>> SocketOptionName.KeepAlive, 1);
>> _socket.Connect (endPoint);
>>
>> return 0;
>> }
>>
>> private static bool IsLocalHost (IPAddress [] ipAddresses)
>> {
>> if (localIpAddresses == null)
>> {
>> localHostname = Dns.GetHostName ();
>> localIpAddresses = Dns.GetHostByName
>> (localHostname).AddressList;
>> }
>>
>> foreach (IPAddress ipaddr in ipAddresses)
>> {
>> foreach (IPAddress ipaddrLocal in
>> localIpAddresses) {
>> if (ipaddrLocal.Equals (ipaddr))
>> return true;
>> }
>> }
>>
>> return false;
>> }
>>
>>
>> private IPHostEntry GetHostByName (string hostname)
>> {
>> IPHostEntry hostInfo = null;
>>
>> // try
>> // {
>> hostInfo = Dns.GetHostByName (_hostName);
>> /* }
>> catch (Exception ex)
>> {
>> Util.TraceError ("Util::GetHostByName exception
>> catched " + ex);
>> }
>> */
>> return hostInfo;
>> }
>>
>> private static IPHostEntry GetHostInfo (string host)
>> {
>> IPHostEntry hostInfo = null;
>>
>> try
>> {
>> hostInfo = Dns.Resolve (host);
>> }
>> catch (Exception ex)
>> {
>> if (Log.Current.IsErrorEnabled)
>> Log.Current.Error
>> (String.Format ("TcpHelper::GetHostInfo
>> {0} exception catched {1}",
>> host, ex.ToString ()));
>> }
>>
>> return hostInfo;
>> }
>>
>> public static IPHostEntry GetHostByAddress (IPAddress
>> ipAddress)
>> {
>> IPHostEntry hostInfo = null;
>>
>> try
>> {
>> hostInfo = Dns.GetHostByAddress (ipAddress);
>> }
>> catch (Exception ex)
>> {
>> if (Log.Current.IsErrorEnabled)
>> Log.Current.Error
>> ("TcpHelper::GetHostByAddress exception catched " + ex);
>> }
>>
>> return hostInfo;
>> }
>>
>> public void ReadTcp ()
>> {
>> if (Log.Current.IsInfoEnabled)
>> Log.Current.Info
>> (String.Format
>> ("TcpHelper::ReadTcp thread started for socket
>> {0}",
>> RemoteEndPoint));
>>
>> int bytesRead = 0;
>> _mustRun = true;
>> bool stopReading = false;
>>
>> try
>> {
>> byte [] header = new byte
>> [IprProtocol.HeaderSize];
>>
>> while ((_mustRun) && (! stopReading))
>> { // read header
>> if (_socket.Poll (PollTimeout,
>> SelectMode.SelectRead))
>> {
>> if (_socket.Available == 0)
>> {
>> if (Log.Current.IsInfoEnabled)
>> Log.Current.Info
>> ("TcpHelper::ReadTcp header no available bytes to read, probably
>> connection closed by peer");
>> stopReading = true;
>> break;
>> }
>>
>> if (_socket.Available >=
>> IprProtocol.HeaderSize)
>> {
>> bytesRead = _socket.Receive
>> (header, IprProtocol.HeaderSize, 0);
>>
>> if (Log.Current.IsInfoEnabled)
>> {
>> Log.Current.Info
>> ("TcpHelper::ReadTcp header " +
>> bytesRead.ToString () +
>> " bytes received");
>> Log.Current.Info
>> (String.Format ("header 0
>> = {0} 1 = {1}",
>> header [0].ToString
>> ("X2"), header [1].ToString ("X2")));
>> }
>>
>> if (bytesRead > 0)
>> { // read command
>>
>> if (bytesRead !=
>> IprProtocol.HeaderSize)
>> {
>> if
>> (Log.Current.IsErrorEnabled)
>> Log.Current.Error
>>
>> ("TcpHelper::ReadTcp: invalid header, " + bytesRead + " bytes
>> received");
>> stopReading = true;
>> break ;
>> }
>>
>> uint commandSize = header [1];
>>
>> if (commandSize <= 0)
>> {
>> if
>> (Log.Current.IsErrorEnabled)
>> Log.Current.Error
>> ("TcpHelper::ReadTcp invalid header, commandSize = " + commandSize);
>> stopReading = true;
>> break;
>> }
>> else
>> {
>> //
>> byte [] command = new byte [commandSize + 1];
>> //
>> command [0] = header [0]; // keep SES
>> command
>> in command buffer
>> byte [] command = new
>> byte [commandSize];
>> bytesRead = 0;
>>
>> while ((_mustRun) && (!
>> stopReading))
>> {
>> if (_socket.Poll
>> (PollTimeout, SelectMode.SelectRead))
>> {
>> if
>> (_socket.Available == 0)
>> {
>> if
>> (Log.Current.IsInfoEnabled)
>>
>> Log.Current.Info ("TcpHelper::ReadTcp command no available bytes
>> to
>> read, probably connection closed by peer");
>>
>> stopReading = true;
>> break;
>> }
>>
>> while
>> ((_mustRun) && (_socket.Available >= 0) && (bytesRead < commandSize))
>> {
>> //
>> bytesRead =
>> _socket.Receive (command, 1, commandSize, 0);
>> bytesRead
>> += _socket.Receive
>>
>> (command, bytesRead,
>>
>> (int) (commandSize - bytesRead),
>> 0);
>>
>> if
>> (Log.Current.IsInfoEnabled)
>>
>> Log.Current.Info ("TcpHelper::ReadTcp command " +
>>
>> bytesRead.ToString () + " bytes received");
>>
>> if
>> (bytesRead == 0)
>> {
>> if
>> (Log.Current.IsInfoEnabled)
>>
>> Log.Current.Info ("TcpHelper::ReadTcp command no available bytes
>> to
>> read, probably connection closed by peer");
>>
>> stopReading = true;
>>
>> break;
>> }
>>
>> if
>> (bytesRead < commandSize)
>> {
>> if
>> (Log.Current.IsInfoEnabled)
>>
>> Log.Current.Info
>>
>> ("TcpHelper::ReadTcp: not enough bytes available, " +
>> bytesRead +
>>
>> " bytes received, " + commandSize + " bytes expected");
>> }
>> }
>>
>> if (bytesRead
>> == commandSize)
>> {
>> if
>> (CallbackReceivedData != null)
>> {
>>
>> CallbackReceivedData (this, new TcpEventData (header, command));
>> }
>> else
>> {
>> if
>> (Log.Current.IsErrorEnabled)
>>
>> Log.Current.Error ("TcpHelper::ReadTcp no callback registered");
>> }
>>
>> break;
>> }
>> }
>> }
>> }
>> }
>> else
>> {
>> if (Log.Current.IsInfoEnabled)
>> Log.Current.Info
>> ("TcpHelper::ReadTcp header no more bytes to read, probably connection
>> closed by peer");
>> stopReading = true;
>> }
>> }
>> }
>> }
>> }
>> catch (Exception ex)
>> {
>> if (ex is SocketException)
>> {
>> /*
>> if (((SocketException)
>> ex).ErrorCode == (int) SocketErrorCodes.InterruptedFunctionCall)
>> Util.TraceOther
>> ("TcpHelper::ReadTcp InterruptedFunctionCall, should be a graceful
>> shutdown");
>> else
>> {
>> */
>> if (Log.Current.IsErrorEnabled)
>> Log.Current.Error ("TcpHelper::ReadTcp
>> error code = " +
>> ((SocketException) ex).ErrorCode);
>> // }
>> }
>> else
>> if (Log.Current.IsErrorEnabled)
>> Log.Current.Error ("TcpHelper::ReadTcp
>> Exception catched " + ex);
>> }
>>
>> if (_mustRun) // not graceful shutdown (not called
>> by
>> Close () )
>> {
>> CloseConnection ();
>>
>> TcpInfoEventArgs tcpInfo =
>> new TcpInfoEventArgs (_socket);
>>
>> if (OnConnectionFailed != null)
>> OnConnectionFailed (this, tcpInfo);
>> else
>> if (Log.Current.IsErrorEnabled)
>> Log.Current.Error ("TcpHelper::ReadTcp no
>> callback defined");
>> }
>> else
>> {
>> if (Log.Current.IsInfoEnabled)
>> Log.Current.Info ("TcpHelper::ReadTcp
>> graceful
>> shutdown");
>> _mustRun = true; // reset flag for new running
>> }
>>
>> if (Log.Current.IsInfoEnabled)
>> Log.Current.Info ("TcpHelper::ReadTcp handling
>> finished host " + _hostName);
>> }
>>
>> private void CloseConnection ()
>> {
>> if (Log.Current.IsInfoEnabled)
>> {
>> if (_hostName.Length > 0)
>> Log.Current.Info
>> (String.Format
>> ("TcpHelper::CloseConnection closing
>> socket {0} on host {1}",
>> RemoteEndPoint, _hostName));
>> else
>> Log.Current.Info
>> (String.Format
>> ("TcpHelper::CloseConnection closing
>> socket {0}",
>> RemoteEndPoint));
>> }
>>
>> if (_socket != null)
>> {
>> if (_socket.Connected)
>> _socket.Shutdown (SocketShutdown.Both);
>> _socket.Close ();
>>
>> _socket = null;
>> }
>> else
>> if (Log.Current.IsErrorEnabled)
>> Log.Current.Error ("TcpHelper::CloseConnection
>> socket is null");
>> }
>>
>> public short Close (bool keepConnected)
>> {
>> if (Log.Current.IsInfoEnabled)
>> {
>> if (_hostName.Length > 0)
>> Log.Current.Info ("TcpHelper::Close closing
>> host " + _hostName);
>> else
>> Log.Current.Info ("TcpHelper::Close closing
>> host " + _socket.RemoteEndPoint);
>> }
>>
>> _mustRun = false;
>>
>> // allow reading thread to terminate
>> Thread.Sleep (PollTimeout);
>>
>> // keepConnected: typically happens after OpenCanal is
>> received,
>> // the MainCommandHandler closes but the IprSocket that
>> has been
>> // given the Tcp socket is using it => keep it opened
>>
>> if ((! keepConnected) && (_socket != null))
>> CloseConnection ();
>>
>> return 0;
>> }
>>
>> public int Send (byte [] data)
>> {
>> int bytesSent = 0;
>>
>> try
>> {
>> if (Log.Current.IsInfoEnabled)
>> Log.Current.Info ("TcpHelper::Send sending "
>> +
>> data.Length +
>> " bytes to client " + RemoteEndPoint);
>>
>> if ((_socket != null) && (_socket.Connected))
>> bytesSent = _socket.Send (data);
>> else
>> if (Log.Current.IsErrorEnabled)
>> Log.Current.Error ("TcpHelper::Send TCP
>> socket
>> not connected");
>>
>> if (bytesSent != data.Length)
>> {
>> if (Log.Current.IsErrorEnabled)
>> Log.Current.Error ("TcpHelper::Send not
>> all bytes sent, " +
>> bytesSent + " != " + data.Length);
>> return -1;
>> }
>> }
>> catch (Exception ex)
>> {
>> if (Log.Current.IsErrorEnabled)
>> Log.Current.Error ("TcpHelper::Send Exception
>> catched: " + ex);
>> return -1;
>> }
>>
>> return bytesSent;
>> }
>> }
>> }
>>
>
>

.

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