Pascal (Lazarus/Delphi)

Enumerate Active SSH Channel Numbers

Demonstrates the Chilkat Ssh.GetChannelNumber method, which returns the channel number at a zero-based enumeration index in the active channel collection. The only argument is the index — an enumeration position, not itself a channel number. Valid indexes run from 0 through NumOpenChannels - 1, and out-of-range indexes return -1.

Background: One SSH connection can carry many simultaneous channels, and this method lets you walk the live set rather than tracking every channel number yourself. The index-versus-channel-number distinction is the key point: index 0 is simply the first channel in the collection and may well be channel number 3. As channels open and close the enumeration shifts, so treat an index as valid only for the moment you read it.

Chilkat Pascal (Lazarus/Delphi) Downloads

Download Chilkat for Pascal (Lazarus/Delphi)

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.Ssh;

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

procedure RunDemo;
var
  success: Boolean;
  ssh: TSsh;
  sshPort: Integer;
  password: string;
  channelA: Integer;
  channelB: Integer;
  n: Integer;
  i: Integer;
  chNum: Integer;

begin
  success := False;

  //  Demonstrates the Ssh.GetChannelNumber method, which returns the channel number at a
  //  zero-based enumeration index in the active channel collection.  The only argument is the
  //  index, which is an enumeration position and not itself a channel number.

  ssh := TSsh.Create;

  sshPort := 22;
  success := ssh.Connect('ssh.example.com',sshPort);
  if (success = False) then
    begin
      WriteLn(ssh.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 := ssh.AuthenticatePw('mySshLogin',password);
  if (success = False) then
    begin
      WriteLn(ssh.LastErrorText);
      Exit;
    end;

  //  Open a couple of channels so the collection has more than one entry.
  channelA := ssh.OpenSessionChannel();
  if (channelA < 0) then
    begin
      WriteLn(ssh.LastErrorText);
      Exit;
    end;

  channelB := ssh.OpenSessionChannel();
  if (channelB < 0) then
    begin
      WriteLn(ssh.LastErrorText);
      Exit;
    end;

  //  Enumerate the active channels.  Valid indexes are 0 through NumOpenChannels - 1.
  n := ssh.NumOpenChannels;
  WriteLn('Open channels: ' + n);

  for i := 0 to n - 1 do
    begin
      chNum := ssh.GetChannelNumber(i);
      WriteLn('Index ' + i + ' is channel number ' + chNum);
    end;

  ssh.Disconnect();


  ssh.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.