Pascal (Lazarus/Delphi)

SSH Tunnel Uncommon Options

Demonstrates the UncommonOptions property, which enables optional behavior for uncommon requirements. The default is an empty string; provide a comma-separated list of keywords to enable more than one option. Available keywords are listed in the reference documentation.

Background: This is a catch-all for narrow workarounds that do not warrant their own properties — forcing a specific signature algorithm, disabling the periodic keep-alive, removing weak MACs, bypassing a VPN on Android, and so on. Most applications never set it. When you do, it is usually to satisfy a particular server's quirk or a specific security requirement, and the exact keyword matters, so consult the documented list rather than guessing.

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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;
  waitForThreadExit: Boolean;

begin
  success := False;

  //  Demonstrates the SshTunnel.UncommonOptions property, which enables optional behavior for
  //  uncommon requirements.  The default is an empty string, appropriate for most applications.
  //  Provide a comma-separated list of keywords to enable more than one option.

  tunnel := TSshTunnel.Create;

  //  For example, disable the periodic keep-alive ignore message and remove weak MAC algorithms
  //  from those offered.  Available keywords are listed in the reference documentation.
  tunnel.UncommonOptions := 'NoKeepAliveIgnoreMsg,no-weak-mac-algs';

  tunnel.DestHostname := 'db.internal.example.com';
  tunnel.DestPort := 5432;

  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;

  listenPort := 1080;
  success := tunnel.BeginAccepting(listenPort);
  if (success = False) then
    begin
      WriteLn(tunnel.LastErrorText);
      Exit;
    end;
  WriteLn('Tunnel established.');

  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.