(Delphi DLL) 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 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, Ssh, Socket;

...

procedure TForm1.Button1Click(Sender: TObject);
var
ssh1: HCkSsh;
success: Boolean;
ssh2: HCkSsh;
socket: HCkSocket;
useTls: Boolean;
maxWaitMillisec: Integer;
responseStatusLine: PWideChar;
responseHeaderLine: PWideChar;
remainderOfHeader: PWideChar;

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

ssh1 := CkSsh_Create();

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

// Authenticate using login/password:
success := CkSsh_AuthenticatePw(ssh1,'ssh1Login','ssh1Password');
if (success <> True) then
  begin
    Memo1.Lines.Add(CkSsh__lastErrorText(ssh1));
    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 := CkSsh_Create();
success := CkSsh_ConnectThroughSsh(ssh2,ssh1,'serverssh2.com',22);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkSsh__lastErrorText(ssh2));
    Exit;
  end;

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

socket := CkSocket_Create();

// 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 := CkSocket_UseSsh(socket,ssh2);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkSocket__lastErrorText(socket));
    Exit;
  end;

// Connect using TLS to www.chilkatsoft.com
// We could also tunnel a bare TCP connection by specifying port 80 with useTls = False.
useTls := True;
maxWaitMillisec := 20000;
success := CkSocket_Connect(socket,'www.chilkatsoft.com',443,useTls,maxWaitMillisec);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkSocket__lastErrorText(socket));
    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.
CkSocket_putStringCharset(socket,'utf-8');

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

// Wait a maximum of 4 seconds while no data is forthcoming:
CkSocket_putMaxReadIdleMs(socket,4000);

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

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

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

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

// Now read the remainder of the response header by reading until a double CRLF is seen:
remainderOfHeader := CkSocket__receiveUntilMatch(socket,#13#10 + #13#10);
if (CkSocket_getLastMethodSuccess(socket) <> True) then
  begin
    Memo1.Lines.Add(CkSocket__lastErrorText(socket));
    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 := CkSocket_Close(socket,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.
CkSsh_Disconnect(ssh2);

CkSsh_Disconnect(ssh1);

CkSsh_Dispose(ssh1);
CkSsh_Dispose(ssh2);
CkSocket_Dispose(socket);

end;