/// <summary>
/// Terminate the connection as client and start listening for protocol messages
/// </summary>
/// <param name="ar"></param>
private void TcpConnectionCallbackClient(IAsyncResult ar)
{
try
{
//Retrive socket information
Socket handler = (Socket)ar.AsyncState;
//complete the connections
handler.EndConnect(ar);
this._log = "Connection created";
NetStateObject netStateObject = new NetStateObject();
netStateObject.socket = handler;
//Start to listen for data from the server
handler.BeginReceive(netStateObject.recBuffer, 0, netStateObject.bufferSize, 0,
new AsyncCallback(ReceiveCallback), netStateObject);
//Wait 0.5sec before return
System.Threading.Thread.Sleep(500);
//Raise the connection state change event
this.OnConnectionStateChanged();
}
catch (Exception ex)
{
this._log = "Error: " + ex.Message;
}
}
/// <summary>
/// Finalizza la connessione, quando la connessione TCP è stabilita solleva evento OnConnectionStateChanged
/// </summary>
/// <param name="ar"></param>
private void TcpConnectionCallbackServer(IAsyncResult ar)
{
try
{
Socket listener = (Socket)ar.AsyncState;
Socket handler = listener.EndAccept(ar);
this._remote = handler;
this._log = "Connection created";
NetStateObject netStateObject = new NetStateObject();
netStateObject.socket = handler;
//Begin receive for remote messages
handler.BeginReceive(netStateObject.recBuffer, 0, netStateObject.bufferSize, 0,
new AsyncCallback(ReceiveCallback), netStateObject);
//Wait 0.5sec before return
System.Threading.Thread.Sleep(500);
//Raise the connection state change event
this.OnConnectionStateChanged();
}
catch (Exception ex)
{
this._log = "Error: " + ex.Message;
}
}
/// <summary>
/// Async received data callback method
/// </summary>
/// <param name="ar">async parameter</param>
private void ReceiveCallback(IAsyncResult ar)
{
try
{
//Retrieve the NetObject and the client socket from the asynchronous state object
NetStateObject netStateObj = (NetStateObject)ar.AsyncState;
Socket handler = netStateObj.socket;
//read data from the remote server
int bytesRead = handler.EndReceive(ar);
if (bytesRead > 0)
{
//There might be more data, so store the data received so far
netStateObj.receivedMex_Sb.Append(Encoding.ASCII.GetString(netStateObj.recBuffer, 0, bytesRead));
//Check if there is a complete message string
string recMex = netStateObj.receivedMex_Sb.ToString();
//first occurence of trailer starting from end of message
int trailerPosition = recMex.IndexOf(NetMessages.packetTrailer);
//last occurence of the header starting from the first trailer, in this way I'm sure to read
//messages from the first to the last received
int headerPosition = recMex.LastIndexOf(NetMessages.packetHeader, trailerPosition);
//if there is a complete messages elaborate it and delete from the string builder of temp object
if (headerPosition > -1 && trailerPosition > -1)
{
int length = trailerPosition - headerPosition + 1;
//Extrapulate the message
lock (this)
{
this._receivedMex = recMex.Substring(headerPosition, length);
//Delete the entire message from the string builder
netStateObj.receivedMex_Sb.Remove(0, trailerPosition + 1);
}
OnMessageReceived();
}
//Waiting for new messages
handler.BeginReceive(netStateObj.recBuffer, 0, netStateObj.bufferSize, 0, new AsyncCallback(ReceiveCallback), netStateObj);
}
}
catch (Exception ex)
{
_log = "Error: " + ex.Message;
}
}