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- //
- // Client.cs
- //
- // Author:
- // Di MERCURIO Sébastien <dimercur@insa-toulouse.fr>
- //
- // Copyright (c) 2018 INSA - DGEI
- //
- // This program is free software: you can redistribute it and/or modify
- // it under the terms of the GNU General Public License as published by
- // the Free Software Foundation, either version 3 of the License, or
- // (at your option) any later version.
- //
- // This program is distributed in the hope that it will be useful,
- // but WITHOUT ANY WARRANTY; without even the implied warranty of
- // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- // GNU General Public License for more details.
- //
- // You should have received a copy of the GNU General Public License
- // along with this program. If not, see <http://www.gnu.org/licenses/>.
-
- using System;
- using System.Net.Sockets;
- using System.Text;
-
- namespace monitor
- {
- /// <summary>
- /// Static class for TCP client
- /// </summary>
- public static class Client
- {
- /// <summary>
- /// Default server name
- /// </summary>
- public const string defaultIP = "localhost";
-
- /// <summary>
- /// Default server port number
- /// </summary>
- public const int defaultPort = 5544;
-
- /// <summary>
- /// Tcp client object
- /// </summary>
- private static TcpClient client = null;
-
- /// <summary>
- /// Stream object used for communication
- /// </summary>
- private static NetworkStream stream = null;
-
- /// <summary>
- /// Size of internal buffer used when reading data from server
- /// </summary>
- private const int BufferMaxSize = 512;
-
- /// <summary>
- /// Internal buffer used when reading data from server
- /// </summary>
- private static byte[] buffer = new byte[BufferMaxSize];
-
- /// <summary>
- /// buffer containing received message from TCP server
- /// Used to concatenate internal buffers into one
- /// </summary>
- private static byte[] receiveBuffer;
-
- private static int initialReceiveBufferIndex = 0;
-
- /// <summary>
- /// String containing received message from tcp server
- /// </summary>
- private static StringBuilder message = new StringBuilder();
- private static int newLength = 1;
- private static int packetCounter = 0;
-
- /// <summary>
- /// Callback to send received message to upper level
- /// </summary>
- public delegate void ReadEvent(string msg, byte[] buffer);
- public static ReadEvent readEvent = null;
-
- /// <summary>
- /// Open connection to server "host", on default port number.
- /// </summary>
- /// <returns>true if connection succeded, false otherwise</returns>
- /// <param name="host">Hostname to connect to</param>
- public static bool Open(string host)
- {
- return Client.Open(host, defaultPort);
- }
-
- /// <summary>
- /// Open connection to server "host", with port number "port"
- /// </summary>
- /// <returns>true if connection succeded, false otherwise</returns>
- /// <param name="host">Hostname to connect to</param>
- /// <param name="port">Port number for connection</param>
- public static bool Open(string host, int port)
- {
- bool status = true;
-
- try
- {
- client = new TcpClient(host, port);
-
- stream = client.GetStream();
-
- // Start reading tcp stream and call "ReadCallback" method when newLength data
- // will be received
- // initially, "newLength" is equal to 1, so first call to ReadCallback
- // will be done after reception of 1 byte.
-
- // received data are stored in buffer
- // Next reading will be done in ReadCallback method
- stream.BeginRead(buffer, 0, newLength, new AsyncCallback(ReadCallback), message);
- }
- catch (ArgumentNullException e)
- {
- Console.WriteLine("ArgumentNullException: " + e);
- status = false;
- }
- catch (SocketException e)
- {
- Console.WriteLine("SocketException: " + e.ToString());
- status = false;
- }
- catch (Exception e)
- {
- Console.WriteLine("Unknown Exception: " + e.ToString());
- status = false;
- }
-
- return status;
- }
-
- /// <summary>
- /// Close connection to server
- /// </summary>
- public static void Close()
- {
- if (stream != null) stream.Close();
- if (client != null) client.Close();
- }
-
- /// <summary>
- /// Callback call by stream.BeginRead after reception of newLength data
- /// </summary>
- /// <param name="ar">Not sure of what is it, but needed for terminate reading</param>
- private static void ReadCallback(IAsyncResult ar)
- {
- if (client.Connected)
- {
- int bytesRead;
-
- try
- {
- // Termintae read operation, and get number of byte stored in buffer
- bytesRead = stream.EndRead(ar);
- }
- catch (ObjectDisposedException e)
- {
- Console.WriteLine("Connection to server dropped: " + e.ToString());
- return;
- }
-
- newLength = 1;
-
- // if number of byte read is not 0, concatenate string and buffer
- if (bytesRead > 0)
- {
- packetCounter++;
-
- if (packetCounter >= 3)
- {
- //Console.WriteLine("Supplementary packet " + packetCounter);
- }
-
- // Append new data to current string (expecting data are ascii)
- message.Append(Encoding.ASCII.GetString(buffer, 0, bytesRead));
-
- // Similarly, append received bytes to current buffer
- if (receiveBuffer == null) receiveBuffer = new byte[bytesRead];
- else Array.Resize<byte>(ref receiveBuffer, initialReceiveBufferIndex + bytesRead); // resize currrent buffer
-
- System.Buffer.BlockCopy(buffer, 0, receiveBuffer, initialReceiveBufferIndex, bytesRead); // and add received data
- initialReceiveBufferIndex = receiveBuffer.Length; // move last index of current buffer
- }
-
- // if it remains received data, prepare for a new reading (get another buffer to append to current one)
- if (client.Available > 0)
- {
- newLength = client.Available;
- if (newLength > BufferMaxSize) newLength = BufferMaxSize;
- else newLength = client.Available;
- }
- else
- {
- // no more data to read, buffer and string can be send to upper level
- readEvent?.Invoke(message.ToString(), receiveBuffer);
-
- message.Clear();
- receiveBuffer = null;
- initialReceiveBufferIndex = 0;
- packetCounter = 0;
- }
-
- // Prepare for reading new data
- if (newLength> BufferMaxSize) newLength = BufferMaxSize;
- if (newLength <= 0) newLength = 1;
- stream.BeginRead(buffer, 0, newLength, new AsyncCallback(ReadCallback), message);
- }
- }
-
- /// <summary>
- /// Write a string to server
- /// </summary>
- /// <returns>Nothing</returns>
- /// <param name="mes">Message to send to server</param>
- public static void Write(string mes)
- {
- if (client.Connected)
- {
- byte[] writeBuffer = Encoding.UTF8.GetBytes(mes);
-
- stream.Write(writeBuffer, 0, mes.Length);
- }
- }
- }
- }
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