(Delphi DLL) Transfer a File using Sockets (TLS or non-TLS)

Demonstrates how to two programs, one a socket writer and the other a socket reader, can transfer a file. The connection can be TLS or a regular non-encrypted TCP connection.

Chilkat for Delphi Downloads Chilkat non-ActiveX DLL for Delphi Chilkat ActiveX DLL for Delphi * The examples here use the non-ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, BinData, Socket;

...

procedure TForm1.Button1Click(Sender: TObject);
var
bdToSend: HCkBinData;
success: Boolean;
sndSock: HCkSocket;
bUseTls: Boolean;
port: Integer;
maxWaitMs: Integer;
numBytes: Integer;
bBigEndian: Boolean;
listenSock: HCkSocket;
rcvSock: HCkSocket;
numBytesComing: Integer;
bdReceived: HCkBinData;
maxWaitMs: Integer;

begin
// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

// On the sending side, we'll load the file into a BinData object and send.
// On the receiving side, we'll read from the socket connection into a BinData, and save to a file.
// This example assumes the file is not crazy-large, and that the entire contents
// can fit into memory.  
// (If the file is too large for memory, there are other ways to send. It just involves streaming or 
// sending the file chunk-by-chunk..)

// This section of code is for the sender.
bdToSend := CkBinData_Create();
success := CkBinData_LoadFile(bdToSend,'somePath/someFile.dat');
// Assume success for the example...

sndSock := CkSocket_Create();
bUseTls := True;
port := 5555;
maxWaitMs := 5000;
success := CkSocket_Connect(sndSock,'some_domain_or_ip.com',port,bUseTls,maxWaitMs);
// Assume success for the example...

// Tell the receiver how many bytes are coming.
numBytes := CkBinData_getNumBytes(bdToSend);
bBigEndian := True;
success := CkSocket_SendInt32(sndSock,numBytes,bBigEndian);

// Send the file data (sends the entire contents of bdToSend).
success := CkSocket_SendBd(sndSock,bdToSend,0,0);

// Get an acknowledgement.
success := CkSocket_ReceiveInt32(sndSock,bBigEndian);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkSocket__lastErrorText(sndSock));
    Exit;
  end;

// Did the receiver get the correct number of bytes?
if (CkSocket_getReceivedInt(sndSock) <> numBytes) then
  begin
    Memo1.Lines.Add('The receiver did not acknowledge with the correct number of bytes.');
    Exit;
  end;

Memo1.Lines.Add('File sent!');

// ------------------------------------------------------------------------------------
// The code below is for the receiving side (running on some other computer..)

listenSock := CkSocket_Create();

success := CkSocket_BindAndListen(listenSock,5555,25);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkSocket__lastErrorText(listenSock));
    Exit;
  end;

// Get the next incoming connection
// Wait a maximum of 20 seconds (20000 millisec)

rcvSock := CkSocket_AcceptNextConnection(listenSock,20000);
if (CkSocket_getLastMethodSuccess(listenSock) = False) then
  begin
    Memo1.Lines.Add(CkSocket__lastErrorText(listenSock));
    Exit;
  end;

// The sender will first send the big-endian integer for the number of bytes
// that are forthcoming..
success := CkSocket_ReceiveInt32(rcvSock,bBigEndian);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkSocket__lastErrorText(rcvSock));
    CkSocket_Dispose(rcvSock);
    Exit;
  end;

numBytesComing := CkSocket_getReceivedInt(rcvSock);

// Receive that many bytes..
bdReceived := CkBinData_Create();
success := CkSocket_ReceiveBdN(rcvSock,numBytesComing,bdReceived);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkSocket__lastErrorText(rcvSock));
    CkSocket_Dispose(rcvSock);
    Exit;
  end;

// Acknowledge the sender by sending back the number of bytes we received.
success := CkSocket_SendInt32(rcvSock,CkBinData_getNumBytes(bdReceived),bBigEndian);

// Close the connection.
maxWaitMs := 20;
CkSocket_Close(rcvSock,maxWaitMs);
CkSocket_Dispose(rcvSock);

// Save the received data to a file.
success := CkBinData_WriteFile(bdReceived,'somePath/someFile.dat');
// Assume success for the example...

Memo1.Lines.Add('File received!');

CkBinData_Dispose(bdToSend);
CkSocket_Dispose(sndSock);
CkSocket_Dispose(listenSock);
CkBinData_Dispose(bdReceived);

end;