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

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

...

procedure TForm1.Button1Click(Sender: TObject);
var
bdToSend: TChilkatBinData;
success: Integer;
sndSock: TChilkatSocket;
bUseTls: Integer;
port: Integer;
maxWaitMs: Integer;
numBytes: Integer;
bBigEndian: Integer;
listenSock: TChilkatSocket;
rcvSock: IChilkatSocket;
numBytesComing: Integer;
bdReceived: TChilkatBinData;
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 := TChilkatBinData.Create(Self);
success := bdToSend.LoadFile('somePath/someFile.dat');
// Assume success for the example...

sndSock := TChilkatSocket.Create(Self);
bUseTls := 1;
port := 5555;
maxWaitMs := 5000;
success := sndSock.Connect('some_domain_or_ip.com',port,bUseTls,maxWaitMs);
// Assume success for the example...

// Tell the receiver how many bytes are coming.
numBytes := bdToSend.NumBytes;
bBigEndian := 1;
success := sndSock.SendInt32(numBytes,bBigEndian);

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

// Get an acknowledgement.
success := sndSock.ReceiveInt32(bBigEndian);
if (success <> 1) then
  begin
    Memo1.Lines.Add(sndSock.LastErrorText);
    Exit;
  end;

// Did the receiver get the correct number of bytes?
if (sndSock.ReceivedInt <> 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 := TChilkatSocket.Create(Self);

success := listenSock.BindAndListen(5555,25);
if (success <> 1) then
  begin
    Memo1.Lines.Add(listenSock.LastErrorText);
    Exit;
  end;

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

rcvSock := listenSock.AcceptNextConnection(20000);
if (listenSock.LastMethodSuccess = 0) then
  begin
    Memo1.Lines.Add(listenSock.LastErrorText);
    Exit;
  end;

// The sender will first send the big-endian integer for the number of bytes
// that are forthcoming..
success := rcvSock.ReceiveInt32(bBigEndian);
if (success <> 1) then
  begin
    Memo1.Lines.Add(rcvSock.LastErrorText);

    Exit;
  end;

numBytesComing := rcvSock.ReceivedInt;

// Receive that many bytes..
bdReceived := TChilkatBinData.Create(Self);
success := rcvSock.ReceiveBdN(numBytesComing,bdReceived.ControlInterface);
if (success <> 1) then
  begin
    Memo1.Lines.Add(rcvSock.LastErrorText);

    Exit;
  end;

// Acknowledge the sender by sending back the number of bytes we received.
success := rcvSock.SendInt32(bdReceived.NumBytes,bBigEndian);

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

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

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