(Delphi ActiveX) TCP or TLS over Multiple Hop SSH to Remote Server

Demonstrates how to use the Chilkat Socket API to connect to a remote server (using TCP or TLS) tunneled through mulitple-hop SSH. The scheme looks like this:

Application => ServerSSH1 => ServerSSH2 => DestinationServer

The ConnectThroughSsh and UseSsh methods are added in Chilkat version 9.5.0.55 to accomplish this task.

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
ssh1: TChilkatSsh;
success: Integer;
ssh2: TChilkatSsh;
socket: TChilkatSocket;
useTls: Integer;
maxWaitMillisec: Integer;
responseStatusLine: WideString;
responseHeaderLine: WideString;
remainderOfHeader: WideString;

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

ssh1 := TChilkatSsh.Create(Self);

// Connect directly to the 1st SSH server.
success := ssh1.Connect('serverssh1.com',22);
if (success <> 1) then
  begin
    Memo1.Lines.Add(ssh1.LastErrorText);
    Exit;
  end;

// Authenticate using login/password:
success := ssh1.AuthenticatePw('ssh1Login','ssh1Password');
if (success <> 1) then
  begin
    Memo1.Lines.Add(ssh1.LastErrorText);
    Exit;
  end;

// Connect through the 1st SSH connection to reach a 2nd SSH server.
// Note: Any number of SSH connections may be simultaneously tunneled through a single
// existing SSH connection.
ssh2 := TChilkatSsh.Create(Self);
success := ssh2.ConnectThroughSsh(ssh1.ControlInterface,'serverssh2.com',22);
if (success <> 1) then
  begin
    Memo1.Lines.Add(ssh2.LastErrorText);
    Exit;
  end;

// Authenticate with ssh2...
success := ssh2.AuthenticatePw('ssh2Login','ssh2Password');
if (success <> 1) then
  begin
    Memo1.Lines.Add(ssh2.LastErrorText);
    Exit;
  end;

socket := TChilkatSocket.Create(Self);

// Tell the socket object to connect to our destination server though the ssh2 tunnel (which itself is routed through ssh1).
// The connection looks like this:  ApplicationSocket(TLS) => ServerSSH1 => ServerSSH2 => DestinationServer
success := socket.UseSsh(ssh2.ControlInterface);
if (success <> 1) then
  begin
    Memo1.Lines.Add(socket.LastErrorText);
    Exit;
  end;

// Connect using TLS to www.chilkatsoft.com
// We could also tunnel a bare TCP connection by specifying port 80 with useTls = 0.
useTls := 1;
maxWaitMillisec := 20000;
success := socket.Connect('www.chilkatsoft.com',443,useTls,maxWaitMillisec);
if (success <> 1) then
  begin
    Memo1.Lines.Add(socket.LastErrorText);
    Exit;
  end;

// Once the multiple hop SSH tunneled connection is setup,  the socket programming
// is identical to the normal case where we have a direct connection.

// Tell the socket object that all text is to be sent in the utf-8 encoding,
// and the text received is assumed to be utf-8.
socket.StringCharset := 'utf-8';

// Send an HTTP HEAD request:
success := socket.SendString('HEAD / HTTP/1.1' + #13#10 + 'Host: www.chilkatsoft.com' + #13#10 + #13#10);
if (success <> 1) then
  begin
    Memo1.Lines.Add(socket.LastErrorText);
    Exit;
  end;

// Wait a maximum of 4 seconds while no data is forthcoming:
socket.MaxReadIdleMs := 4000;

// Get the 1st response line, which should be "HTTP/1.1 200 OK"
responseStatusLine := socket.ReceiveToCRLF();
if (socket.LastMethodSuccess <> 1) then
  begin
    Memo1.Lines.Add(socket.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add('StatusLine: ' + responseStatusLine);

// Now get the 1st line of the response header:
responseHeaderLine := socket.ReceiveToCRLF();
if (socket.LastMethodSuccess <> 1) then
  begin
    Memo1.Lines.Add(socket.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add('HeaderLine: ' + responseHeaderLine);

// Now read the remainder of the response header by reading until a double CRLF is seen:
remainderOfHeader := socket.ReceiveUntilMatch(#13#10 + #13#10);
if (socket.LastMethodSuccess <> 1) then
  begin
    Memo1.Lines.Add(socket.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add('Remainder: ' + remainderOfHeader);

// Close the connection with the server.  This closes the tunnel through ssh2.
// Wait a max of 20 seconds (20000 millsec)
success := socket.Close(20000);

// Close the connection with ssh2.  (This closes the the tunnel through ssh1.)
// The connection with ssh1 is still alive, and may be used for more connections.
ssh2.Disconnect();

ssh1.Disconnect();
end;