Pascal (Lazarus/Delphi)

SSH Tunnel with Dynamic Port Forwarding

See more SSH Examples

Demonstrates how to start a background thread that runs a portable SSH tunnel w/ dynamic port forwarding that the foreground thread can use for establishing connections through an SSH tunnel. Pascal (Lazarus/Delphi)

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.SshTunnel,
  Chilkat.Http;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  tunnel: TSshTunnel;
  sshHostname: string;
  sshPort: Integer;
  url: string;
  http: THttp;
  html: string;
  waitForThreadExit: Boolean;

begin
  success := False;

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

  success := False;

  tunnel := TSshTunnel.Create;

  sshHostname := 'sftp.example.com';
  sshPort := 22;

  //  Connect to an SSH server and establish the SSH tunnel:
  success := tunnel.Connect(sshHostname,sshPort);
  if (success <> True) then
    begin
      WriteLn(tunnel.LastErrorText);
      Exit;
    end;

  //  Authenticate with the SSH server via a login/password
  //  or with a public key.  
  //  This example demonstrates SSH password authentication.
  success := tunnel.AuthenticatePw('mySshLogin','mySshPassword');
  if (success <> True) then
    begin
      WriteLn(tunnel.LastErrorText);
      Exit;
    end;

  //  Indicate that the background SSH tunnel thread will behave as a SOCKS proxy server
  //  with dynamic port forwarding:
  tunnel.DynamicPortForwarding := True;

  //  We may optionally require that connecting clients authenticate with our SOCKS proxy server.
  //  To do this, set an inbound username/password.  Any connecting clients would be required to 
  //  use SOCKS5 with the correct username/password.
  //  If no inbound username/password is set, then our SOCKS proxy server will accept both
  //  SOCKS4 and SOCKS5 unauthenticated connections.

  tunnel.InboundSocksUsername := 'chilkat123';
  tunnel.InboundSocksPassword := 'password123';

  //  Start the listen/accept thread to begin accepting SOCKS proxy client connections.
  //  Listen on port 1080.
  success := tunnel.BeginAccepting(1080);
  if (success <> True) then
    begin
      WriteLn(tunnel.LastErrorText);
      Exit;
    end;

  //  Now that a background thread is running a SOCKS proxy server that forwards connections
  //  through an SSH tunnel, it is possible to use any Chilkat implemented protocol that is SOCKS capable,
  //  such as HTTP, POP3, SMTP, IMAP, FTP, etc.  The protocol may use SSL/TLS because the SSL/TLS
  //  will be passed through the SSH tunnel to the end-destination.  Also, any number of simultaneous
  //  connections may be routed through the SSH tunnel.

  //  For this example, let's do a simple HTTPS request:
  url := 'https://www.ethereum.org/';

  http := THttp.Create;

  //  Indicate that the HTTP object is to use our portable SOCKS proxy/SSH tunnel running in our background thread.
  http.SocksHostname := 'localhost';
  http.SocksPort := 1080;
  http.SocksVersion := 5;
  http.SocksUsername := 'chilkat123';
  http.SocksPassword := 'password123';

  http.SendCookies := True;
  http.SaveCookies := True;
  http.CookieDir := 'memory';

  //  Do the HTTPS page fetch (through the SSH tunnel)
  html := http.QuickGetStr(url);
  if (http.LastMethodSuccess <> True) then
    begin
      WriteLn(http.LastErrorText);
      Exit;
    end;

  //  Stop the background listen/accept thread:
  waitForThreadExit := True;
  success := tunnel.StopAccepting(waitForThreadExit);
  if (success <> True) then
    begin
      WriteLn(tunnel.LastErrorText);
      Exit;
    end;

  //  Close the SSH tunnel (would also kick any remaining connected clients).
  success := tunnel.CloseTunnel(waitForThreadExit);
  if (success <> True) then
    begin
      WriteLn(tunnel.LastErrorText);
      Exit;
    end;


  tunnel.Free;
  http.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.