Monitor
Client.cs
Go to the documentation of this file.
1 //
2 // Client.cs
3 //
4 // Author:
5 // Di MERCURIO Sébastien <dimercur@insa-toulouse.fr>
6 //
7 // Copyright (c) 2018 INSA - DGEI
8 //
9 // This program is free software: you can redistribute it and/or modify
10 // it under the terms of the GNU General Public License as published by
11 // the Free Software Foundation, either version 3 of the License, or
12 // (at your option) any later version.
13 //
14 // This program is distributed in the hope that it will be useful,
15 // but WITHOUT ANY WARRANTY; without even the implied warranty of
16 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 // GNU General Public License for more details.
18 //
19 // You should have received a copy of the GNU General Public License
20 // along with this program. If not, see <http://www.gnu.org/licenses/>.
21 
22 using System;
23 using System.Net.Sockets;
24 using System.Text;
25 
26 namespace monitor
27 {
31  public static class Client
32  {
36  public const string defaultIP = "localhost";
37 
41  public const int defaultPort = 4500;
42 
46  private static TcpClient client = null;
47 
51  private static NetworkStream stream = null;
52 
56  private const int BufferMaxSize = 512;
57 
61  private static byte[] buffer = new byte[BufferMaxSize];
62 
67  private static byte[] receiveBuffer;
68 
69  private static int initialReceiveBufferIndex = 0;
70 
74  private static StringBuilder message = new StringBuilder();
75  private static int newLength = 1;
76  private static int packetCounter = 0;
77 
81  public delegate void ReadEvent(string msg, byte[] buffer);
82  public static ReadEvent readEvent = null;
83 
89  public static bool Open(string host)
90  {
91  return Client.Open(host, defaultPort);
92  }
93 
100  public static bool Open(string host, int port)
101  {
102  bool status = true;
103 
104  try
105  {
106  client = new TcpClient(host, port);
107 
108  stream = client.GetStream();
109 
110  // Start reading tcp stream and call "ReadCallback" method when newLength data
111  // will be received
112  // initially, "newLength" is equal to 1, so first call to ReadCallback
113  // will be done after reception of 1 byte.
114 
115  // received data are stored in buffer
116  // Next reading will be done in ReadCallback method
117  stream.BeginRead(buffer, 0, newLength, new AsyncCallback(ReadCallback), message);
118  }
119  catch (ArgumentNullException e)
120  {
121  Console.WriteLine("ArgumentNullException: " + e);
122  status = false;
123  }
124  catch (SocketException e)
125  {
126  Console.WriteLine("SocketException: " + e.ToString());
127  status = false;
128  }
129  catch (Exception e)
130  {
131  Console.WriteLine("Unknown Exception: " + e.ToString());
132  status = false;
133  }
134 
135  return status;
136  }
137 
141  public static void Close()
142  {
143  if (stream != null) stream.Close();
144  if (client != null) client.Close();
145  }
146 
151  private static void ReadCallback(IAsyncResult ar)
152  {
153  if (client.Connected)
154  {
155  int bytesRead;
156 
157  try
158  {
159  // Termintae read operation, and get number of byte stored in buffer
160  bytesRead = stream.EndRead(ar);
161  }
162  catch (ObjectDisposedException e)
163  {
164  Console.WriteLine("Connection to server dropped: " + e.ToString());
165  return;
166  }
167 
168  newLength = 1;
169 
170  // if number of byte read is not 0, concatenate string and buffer
171  if (bytesRead > 0)
172  {
173  packetCounter++;
174 
175  if (packetCounter >= 3)
176  {
177  //Console.WriteLine("Supplementary packet " + packetCounter);
178  }
179 
180  // Append new data to current string (expecting data are ascii)
181  message.Append(Encoding.ASCII.GetString(buffer, 0, bytesRead));
182 
183  // Similarly, append received bytes to current buffer
184  if (receiveBuffer == null) receiveBuffer = new byte[bytesRead];
185  else Array.Resize<byte>(ref receiveBuffer, initialReceiveBufferIndex + bytesRead); // resize currrent buffer
186 
187  System.Buffer.BlockCopy(buffer, 0, receiveBuffer, initialReceiveBufferIndex, bytesRead); // and add received data
188  initialReceiveBufferIndex = receiveBuffer.Length; // move last index of current buffer
189  }
190 
191  // if it remains received data, prepare for a new reading (get another buffer to append to current one)
192  if (client.Available > 0)
193  {
194  newLength = client.Available;
195  if (newLength > BufferMaxSize) newLength = BufferMaxSize;
196  else newLength = client.Available;
197  }
198  else
199  {
200  // no more data to read, buffer and string can be send to upper level
201  readEvent?.Invoke(message.ToString(), receiveBuffer);
202 
203  message.Clear();
204  receiveBuffer = null;
205  initialReceiveBufferIndex = 0;
206  packetCounter = 0;
207  }
208 
209  // Prepare for reading new data
210  stream.BeginRead(buffer, 0, newLength, new AsyncCallback(ReadCallback), message);
211  }
212  }
213 
219  public static void Write(string mes)
220  {
221  if (client.Connected)
222  {
223  byte[] writeBuffer = Encoding.UTF8.GetBytes(mes);
224 
225  stream.Write(writeBuffer, 0, mes.Length);
226  }
227  }
228  }
229 }
static byte [] buffer
Internal buffer used when reading data from server
Definition: Client.cs:61
static int packetCounter
Definition: Client.cs:76
static int initialReceiveBufferIndex
Definition: Client.cs:69
const int defaultPort
Default server port number
Definition: Client.cs:41
static TcpClient client
Tcp client object
Definition: Client.cs:46
static void Write(string mes)
Write a string to server
Definition: Client.cs:219
static byte [] receiveBuffer
buffer containing received message from TCP server Used to concatenate internal buffers into one ...
Definition: Client.cs:67
const int BufferMaxSize
Size of internal buffer used when reading data from server
Definition: Client.cs:56
static NetworkStream stream
Stream object used for communication
Definition: Client.cs:51
const string defaultIP
Default server name
Definition: Client.cs:36
delegate void ReadEvent(string msg, byte[] buffer)
Callback to send received message to upper level
static StringBuilder message
String containing received message from tcp server
Definition: Client.cs:74
static int newLength
Definition: Client.cs:75
static bool Open(string host, int port)
Open connection to server "host", with port number "port"
Definition: Client.cs:100
static bool Open(string host)
Open connection to server "host", on default port number.
Definition: Client.cs:89
Static class for TCP client
Definition: Client.cs:31
static void Close()
Close connection to server
Definition: Client.cs:141
static ReadEvent readEvent
Definition: Client.cs:82
static void ReadCallback(IAsyncResult ar)
Callback call by stream.BeginRead after reception of newLength data
Definition: Client.cs:151