Pascal (Lazarus/Delphi)

Get an SSH Tunnel's Current State (Diagnostics)

Demonstrates the Chilkat SshTunnel.GetCurrentState method, which returns an XML snapshot describing the tunnel manager, SSH channels, and current tunnel clients. It takes no arguments and is intended for diagnostics and monitoring.

Background: Because the tunnel forwards traffic on a background thread, there is no natural place in your code to observe what it is doing at a given moment. GetCurrentState provides that visibility — byte counts, active channels, and connected clients — as structured XML suited to logging or a monitoring dashboard. It is a read-only snapshot and does not affect the tunnel.

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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;

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

procedure RunDemo;
var
  success: Boolean;
  tunnel: TSshTunnel;
  sshPort: Integer;
  password: string;
  listenPort: Integer;
  stateXml: string;
  waitForThreadExit: Boolean;

begin
  success := False;

  //  Demonstrates the SshTunnel.GetCurrentState method, which returns an XML snapshot describing the
  //  tunnel manager, SSH channels, and current tunnel clients.  It takes no arguments and is
  //  intended for diagnostics and monitoring.

  tunnel := TSshTunnel.Create;

  //  The tunnel forwards accepted local connections to this destination through the SSH server.
  tunnel.DestHostname := 'db.internal.example.com';
  tunnel.DestPort := 5432;

  //  Connect to the SSH server.  This performs the TCP/proxy connection and SSH handshake, but
  //  does not authenticate yet.
  sshPort := 22;
  success := tunnel.Connect('ssh.example.com',sshPort);
  if (success = False) then
    begin
      WriteLn(tunnel.LastErrorText);
      Exit;
    end;

  //  Normally you would not hard-code the password in source.  You should instead obtain it
  //  from an interactive prompt, environment variable, or a secrets vault.
  password := 'mySshPassword';

  success := tunnel.AuthenticatePw('mySshLogin',password);
  if (success = False) then
    begin
      WriteLn(tunnel.LastErrorText);
      Exit;
    end;

  //  Begin accepting so there is live tunnel state to inspect.
  listenPort := 1080;
  success := tunnel.BeginAccepting(listenPort);
  if (success = False) then
    begin
      WriteLn(tunnel.LastErrorText);
      Exit;
    end;

  //  Get a diagnostic snapshot of the tunnel's current state as XML.
  stateXml := tunnel.GetCurrentState();
  if (tunnel.LastMethodSuccess = False) then
    begin
      WriteLn(tunnel.LastErrorText);
      Exit;
    end;
  WriteLn(stateXml);

  waitForThreadExit := True;
  success := tunnel.CloseTunnel(waitForThreadExit);
  if (success = False) then
    begin
      WriteLn(tunnel.LastErrorText);
      Exit;
    end;


  tunnel.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.