/// <summary>
/// Take the incoming data from a client and convert it into a TFMS_Data object
/// </summary>
/// <param name="socket">the socket that connects the server and the client</param>
/// <param name="info">the information about the client from the socket</param>
/// <param name="result">the result of the connection attempt</param>
/// <returns></returns>
private TFMS_Data extractData(Socket socket, TFMS_ClientInfo info, IAsyncResult result)
{
try
{
int numBytesReceived = socket.EndReceive(result); // EndReceive returns how many bytes were received
byte[] temp = new byte[numBytesReceived];
// the buffer might not be used for the first Received message so check if it exists
// otherwise use the default buffer
if (info == null || info.buffer == null)
Array.Copy(byteData, temp, numBytesReceived);
else
Array.Copy(info.buffer, temp, numBytesReceived);
// parse the bytes and turn it into a TFMS_Data object
return new TFMS_Data(temp);
}
catch (SocketException)
{
// if something goes wrong, logoff the client
return new TFMS_Data(TFMS_Command.Logout, null, getNamefromSocket(socket));
}
}
/// <summary>
/// this hadles the actual message forwarding ect.
/// you should never call this function directly
/// </summary>
/// <param name="result">this encapsulates the Socket of the client</param>
public void OnReceive(IAsyncResult result)
{
// get the socket that received data
Socket clientSocket = (Socket)result.AsyncState;
// get the ClientInfo from the connected client
TFMS_ClientInfo CI = null;
if (findIndexFromClient(clientList, clientSocket) >= 0)
CI = clientList[findIndexFromClient(clientList, clientSocket)];
Console.WriteLine("\n****************************************");
Console.WriteLine("Data Received from {0}", getNamefromSocket(clientSocket));
// attempt to get the data from the client and convert it into TFMS_Data object
TFMS_Data msgReceived = extractData(clientSocket, CI, result);
TFMS_Data msgToSend = new TFMS_Data();
msgToSend.cmdCommand = msgReceived.cmdCommand;
msgToSend.strName = msgReceived.strName;
#region Interpret incoming message command
// set the message to send, client info buffer size, and client info based on the incoming command
switch (msgReceived.cmdCommand)
{
case TFMS_Command.Login: // new client logging in
#region Login command
Console.WriteLine("Received login from {0}", getNamefromSocket(clientSocket));
// tell the server a logon was requested
logonRequested(msgReceived);
// add the new client to the current list of clients
TFMS_ClientInfo clientInfo = new TFMS_ClientInfo(clientSocket, msgReceived.strName);
clientList.Add(clientInfo);
// pass the incoming client's name to other clients
msgToSend.strMessage = msgReceived.strName;
clientInfo.buffer = new byte[TFMS_Constants.BUFFER_SIZE]; // dimension the clients buffer.
CI = clientInfo; // CI would not have been found before since its not in the clientList so just add it now
#endregion
break;
case TFMS_Command.Logout: // client logging out
#region Logout command
Console.WriteLine("Received Logout from {0}", getNamefromSocket(clientSocket));
// tell the server a logout was requested
logoffRequested(msgReceived);
// remove the client from the list of connected clients.
clientList.RemoveAt(findIndexFromClient(clientList, clientSocket));
clientSocket.Close();
// pass the client's name to other clients
msgToSend.strMessage = msgReceived.strName;
#endregion
break;
case TFMS_Command.List: // client requesting a list of all clients
#region List command
Console.WriteLine("Received List request from {0}", getNamefromSocket(clientSocket));
// tell the server a list of clients was requested
listRequested(msgReceived);
// get the list of all currently connected clients
msgToSend = GetClientListMessage();
// send the message to a single client
sendTFMSmsg(msgToSend, clientSocket, new AsyncCallback(OnSend));
#endregion
break;
case TFMS_Command.Message: // incoming message to be broadcast
#region Message command
Console.WriteLine("Received TFM from {0} (size={1})", getNamefromSocket(clientSocket), CI.buffer.Length);
// tell the server a message broadcast was requested
relayRequested(msgReceived);
// copy the message to the server's outgoing message field
msgToSend.strMessage = msgReceived.strMessage;
#endregion
break;
case TFMS_Command.MsgLen: // incoming message is greater than the current buffer size
#region Long Message command
Console.WriteLine("Received long TFM from {0} (size={1})", getNamefromSocket(clientSocket), CI.buffer.Length);
// resize the buffer for the incoming large message
CI.buffer = new byte[int.Parse(msgReceived.strMessage) + TFMS_Constants.BUFFER_SIZE];
#endregion
break;
default: // unrecognizable command
#region Unknown command
// we gracefully fail and gtfoh
Console.WriteLine("Cant interpret command! Aborting this relay.");
Console.WriteLine("BeginReceive from {0}", getNamefromSocket(clientSocket));
// restart the receive command
clientSocket.BeginReceive(CI.buffer, 0, CI.buffer.Length, SocketFlags.None, new AsyncCallback(OnReceive), clientSocket);
return;
#endregion
}
#endregion
// send the message to every client logged in to the server
broadcastToClients(msgToSend, clientList);
// after a message is broadcast, begin listening for more incoming messages
// NOTE: if many users are logged in at once, the broadcast method could block other incoming messages
// for future iterations of TFMS, we want the receiving command to run on a separate thread from the sending command
if (msgReceived.cmdCommand != TFMS_Command.Logout)
{
Console.WriteLine("Waiting for data from {0}", getNamefromSocket(clientSocket));
clientSocket.BeginReceive(CI.buffer, 0, CI.buffer.Length, SocketFlags.None, new AsyncCallback(OnReceive), clientSocket);
}
}