/// <summary>
/// Begins to send a file through the RendezvousData's Transfer socket
/// </summary>
/// <remarks>This method cancels the direct connection itself rather than throw an exception</remarks>
private void BeginSendFile(RendezvousData rd)
{
// Open the file for reading
try
{
rd.DirectConnection.DataChunk = new byte[8192];
rd.DirectConnection.DataStream = (new StreamReader(rd.DirectConnection.LocalFileName, false)).BaseStream;
rd.DirectConnection.StreamPosition = 0;
}
catch (Exception ex)
{
rd.DirectConnection.CancelTransfer("Can't open file for reading");
return;
}
// Send a PROMPT message and receive an ACK message
try
{
SendFileTransmitterHandshake(rd);
}
catch (Exception ex)
{
rd.DirectConnection.CancelTransfer(ex.Message);
return;
}
// Signal the parent session that we've started transfering a file
rd.ParentSession.OnFileTransferProgress(
RendezvousManager.GetKeyFromCookie(rd.Cookie),
0, rd.DirectConnection.Header.Size);
// Send the first chunk
SendFileTransmitterSendChunk(rd);
}
/// <summary>
/// Called when a chunk of data has been sent to the remote client
/// </summary>
/// <param name="res">An <see cref="IAsyncResult"/> object</param>
private void SendFileTransmitterSendEnd(IAsyncResult res)
{
RendezvousData rd = (RendezvousData)res.AsyncState;
int bytessent = 0;
try
{
bytessent = rd.DirectConnection.Transfer.EndSend(res);
}
catch (Exception ex)
{
rd.DirectConnection.CancelTransfer(ex.Message);
return;
}
rd.DirectConnection.StreamPosition += (uint)bytessent;
// Signal parent session of the progress
rd.ParentSession.OnFileTransferProgress(
RendezvousManager.GetKeyFromCookie(rd.Cookie),
rd.DirectConnection.StreamPosition,
rd.DirectConnection.Header.Size);
// If all the file has been sent, wait for the acknowledgement message
// and close up shop. Otherwise, send another chunk
if (rd.DirectConnection.StreamPosition == rd.DirectConnection.Header.Size)
{
byte[] receivedone = new byte[256];
try
{
rd.DirectConnection.Transfer.Receive(receivedone);
}
catch (Exception ex)
{
rd.DirectConnection.CancelTransfer(ex.Message);
return;
}
// Check checksums?
rd.DirectConnection.CompleteTransfer();
}
else
{
SendFileTransmitterSendChunk(rd);
}
}
/// <summary>
/// The callback function for socket reads during a file transfer
/// </summary>
/// <param name="res">An <see cref="IAsyncResult"/> object</param>
private void SendFileTransferReceive(IAsyncResult res)
{
int bytesread = 0;
RendezvousData rd = (RendezvousData)res.AsyncState;
DirectConnectInfo fti = rd.DirectConnection;
// End the async receive operation
try
{
bytesread = fti.Transfer.EndReceive(res);
if (bytesread == 0)
{
throw new Exception("Remote client cancelled transfer");
}
}
catch (Exception ex)
{
rd.DirectConnection.CancelTransfer(ex.Message);
return;
}
// Write the received data out to the file
try
{
fti.DataStream.Write(fti.DataChunk, 0, bytesread);
fti.StreamPosition += (uint)bytesread;
}
catch (Exception ex)
{
rd.DirectConnection.CancelTransfer(ex.Message);
return;
}
// Checksum the received chunk
fti.Header.ReceivedChecksum = ChecksumChunk(fti.DataChunk, (uint)bytesread, fti.Header.ReceivedChecksum);
// Signal progress to the parent session
rd.ParentSession.OnFileTransferProgress(
RendezvousManager.GetKeyFromCookie(rd.Cookie),
rd.DirectConnection.StreamPosition,
rd.DirectConnection.Header.Size);
// Check to see if the transfer has finished
if (fti.StreamPosition >= fti.Header.Size)
{
fti.DataChunk = null;
fti.DataStream.Close();
// Send out the acknowledgement, compare the checksums, and finish up
SendFileReceiverDone(rd);
if (fti.Header.ReceivedChecksum != fti.Header.Checksum)
{
rd.DirectConnection.CancelTransfer("Received data does not match expected checksum");
return;
}
rd.DirectConnection.CompleteTransfer();
}
else
{
// Keep receiving asynchronously
fti.Transfer.BeginReceive(fti.DataChunk, 0, fti.DataChunk.Length,
SocketFlags.None, new AsyncCallback(SendFileTransferReceive), rd);
}
}
/// <summary>
/// Receives the PROMPT message and responds with an ACK message, then prepares the transfer socket to receive data
/// </summary>
/// <param name="rd">The <see cref="RendezvousData"/> object receiving a file</param>
private void BeginReceiveFile(RendezvousData rd)
{
byte[] filetransferheader = null;
int index = 0;
// Read in 256 bytes, PROMPT type and blank cookie
filetransferheader = new byte[256];
try
{
while (index < filetransferheader.Length)
{
index += rd.DirectConnection.Transfer.Receive(
filetransferheader,
index,
filetransferheader.Length - index,
SocketFlags.None);
}
}
catch (Exception ex)
{
string message = "Error negotiating file transfer:" + Environ.NewLine + ex.Message;
throw new Exception(message);
}
index = 8;
DirectConnectInfo dci = rd.DirectConnection;
//Marshal.ByteArrayToFTI(filetransferheader, ref index, ref dci);
rd.DirectConnection = dci; // Just to be sure
// Respond with the same header, but with the ACK type and the ICBM cookie set
index = 6;
Marshal.InsertUshort(filetransferheader, 0x0202, ref index);
Marshal.CopyArray(rd.Cookie, filetransferheader, 0, ref index);
index = 0;
try
{
while (index < filetransferheader.Length)
{
index += rd.DirectConnection.Transfer.Send(
filetransferheader,
index,
filetransferheader.Length - index,
SocketFlags.None);
}
}
catch (Exception ex)
{
string message = "Error negotiating file transfer:" + Environ.NewLine + ex.Message;
throw new Exception(message);
}
// Open the file for writing
try
{
rd.DirectConnection.DataChunk = new byte[8192];
rd.DirectConnection.DataStream = (new StreamWriter(rd.DirectConnection.LocalFileName, false)).BaseStream;
rd.DirectConnection.StreamPosition = 0;
}
catch (Exception)
{
throw new Exception("Can't open target file for writing");
}
// Signal the parent session that the file transfer has started
rd.ParentSession.OnFileTransferProgress(RendezvousManager.GetKeyFromCookie(rd.Cookie),
0, rd.DirectConnection.Header.Size);
// Start receiving data
rd.DirectConnection.Transfer.BeginReceive(rd.DirectConnection.DataChunk, 0,
rd.DirectConnection.DataChunk.Length,
SocketFlags.None, new AsyncCallback(SendFileTransferReceive), rd);
}