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27
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1 using System;
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2 using System.Net;
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3 using System.Net.Sockets;
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4 using System.Text;
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5 using System.Threading;
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6 using Common.Messages;
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7 using GalaSoft.MvvmLight.Messaging;
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8 using Server.Interfaces;
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9
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10 namespace Server.Listeners
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11 {
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12 public class AsyncSocketListener : IListener
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13 {
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14 public bool IsListening { get; set; }
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15 private readonly int _portNumber;
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16
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17 // Thread signal.
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18 public static ManualResetEvent AllDone = new ManualResetEvent(false);
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19
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20 public AsyncSocketListener(int portNumber)
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21 {
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22 IsListening = false;
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23 _portNumber = portNumber;
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24 }
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25
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26 public void Start()
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27 {
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28
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28 if (IsListening)
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29 {
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30 Messenger.Default.Send(new SocketLogMessage() { Body = "Already listening..." });
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31 return;
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32 }
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33 Messenger.Default.Send(new SocketLogMessage() { Body = "Opening listener..." });
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27
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34
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35 // Data buffer for incoming data.
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36 var bytes = new Byte[1024];
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37
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38 // Establish the local endpoint for the socket
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39 var ipHostInfo = Dns.GetHostEntry(Dns.GetHostName());
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40 var ipAddress = ipHostInfo.AddressList[2];
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41 var localEndPoint = new IPEndPoint(ipAddress, _portNumber);
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42
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43 // Create a TCP/IP socket.
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44 using(var listener = new Socket(
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45 AddressFamily.InterNetwork,
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46 SocketType.Stream,
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47 ProtocolType.Tcp))
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48 {
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49
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50 // Bind the socket to the local endpoint and listen for incoming connections.
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28
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51 try
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52 {
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53 listener.Bind(localEndPoint);
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54 listener.Listen(100);
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55 IsListening = true;
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56
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57 Messenger.Default.Send(new SocketLogMessage() { Body = "Listener opened" });
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58
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28
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59 while (IsListening)
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60 {
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61 // Set the event to nonsignaled state.
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62 AllDone.Reset();
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63
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64 // Start an asynchronous socket to listen for connections.
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65 Messenger.Default.Send(new SocketLogMessage() { Body = "Waiting for a connection..." });
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66
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67 listener.BeginAccept(
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68 AcceptCallback,
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69 listener);
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70
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71 // Wait until a connection is made before continuing.
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72 AllDone.WaitOne();
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73 }
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74
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75 if (listener.Connected)
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76 {
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77 Messenger.Default.Send(new SocketLogMessage() { Body = "Shutting down listener..." });
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78 listener.Shutdown(SocketShutdown.Both);
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79
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80 Messenger.Default.Send(new SocketLogMessage() { Body = "Disconnecting listener..." });
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81 listener.Disconnect(true);
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82 }
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83
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27
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84 }
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28
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85 catch (Exception e)
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86 {
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87 Messenger.Default.Send(new SocketLogMessage() { Body = e.Message });
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88 }
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89 finally
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90 {
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91 Messenger.Default.Send(new SocketLogMessage() { Body = "Connection closed." });
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92 }
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27
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93 }
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94 }
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95
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96 public void AcceptCallback(IAsyncResult ar)
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97 {
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98 // Signal the main thread to continue.
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99 AllDone.Set();
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100
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101 // Get the socket that handles the client request.
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102 var listener = (Socket) ar.AsyncState;
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103 var handler = listener.EndAccept(ar);
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104
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105 // Create the state object.
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106 var state = new StateObject {WorkSocket = handler};
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107
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108 handler.BeginReceive(
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109 state.Buffer,
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110 0,
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111 StateObject.BufferSize,
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112 0,
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113 ReadCallback,
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114 state);
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115 }
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116
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117 public void ReadCallback(IAsyncResult ar)
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118 {
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119 var content = String.Empty;
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120
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121 // Retrieve the state object and the handler socket
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122 // from the asynchronous state object.
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123 var state = (StateObject)ar.AsyncState;
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124 var handler = state.WorkSocket;
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125
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126 // Read data from the client socket.
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127 var bytesRead = handler.EndReceive(ar);
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128
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129 if (bytesRead <= 0) return;
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130
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131 // There might be more data, so store the data received so far.
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132 state.Sb.Append(
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133 Encoding.ASCII.GetString(
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134 state.Buffer,
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135 0,
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136 bytesRead));
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137
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138 // Check for end-of-file tag. If it is not there, read
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139 // more data.
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140 content = state.Sb.ToString();
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141 if (content.IndexOf("<EOF>") > -1)
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142 {
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143 // All the data has been read from the
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144 // client. Display it on the console.
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145
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146 Messenger.Default.Send(
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147 new SocketLogMessage()
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148 {
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149 Body = string.Format(
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150 "Read {0} bytes from socket. \n Data : {1}",
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151 content.Length,
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152 content)
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153 });
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154
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155 // Echo the data back to the client.
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156 Send(handler, "The following message was received: " + content);
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157 }
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158 else
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159 {
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160 // Not all data received. Get more.
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161 handler.BeginReceive(
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162 state.Buffer,
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163 0,
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164 StateObject.BufferSize,
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165 0,
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166 ReadCallback,
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167 state);
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168 }
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169 }
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170
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171 private void Send(Socket handler, String data)
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172 {
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173 // Convert the string data to byte data using ASCII encoding.
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174 var byteData = Encoding.ASCII.GetBytes(data);
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175
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176 // Begin sending the data to the remote device.
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177 handler.BeginSend(
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178 byteData,
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179 0,
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180 byteData.Length,
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181 0,
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182 SendCallback,
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183 handler);
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184 }
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185
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186 private void SendCallback(IAsyncResult ar)
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187 {
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188 try
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189 {
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190 // Retrieve the socket from the state object.
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191 var handler = (Socket)ar.AsyncState;
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192
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193 // Complete sending the data to the remote device.
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194 var bytesSent = handler.EndSend(ar);
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195
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196 Messenger.Default.Send(new SocketLogMessage() { Body = string.Format("Sent {0} bytes to client.", bytesSent) });
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197
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198 handler.Shutdown(SocketShutdown.Both);
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199 handler.Close();
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200 }
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201 catch (Exception e)
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202 {
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203 Messenger.Default.Send(new SocketLogMessage() { Body = e.Message });
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204 }
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205 }
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206
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207 public void Stop()
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208 {
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209 if (IsListening == false) return;
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210
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211 Messenger.Default.Send(new SocketLogMessage() { Body = "Closing connection..." });
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212 IsListening = false;
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28
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213 AllDone.Set();
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27
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214 }
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215 }
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28
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216
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217 // State object for reading client data asynchronously
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218 public class StateObject
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219 {
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220 // Client socket.
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221 public Socket WorkSocket;
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222
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223 // Size of receive buffer.
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224 public const int BufferSize = 1024;
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225
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226 // Receive buffer.
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227 public byte[] Buffer = new byte[BufferSize];
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228
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229 // Received data string.
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230 public StringBuilder Sb = new StringBuilder();
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231 }
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27
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232 } |
