Collect Completed SSH Commands with QuickCmdCheck

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Demonstrates the Chilkat Ssh.QuickCmdCheck method, which waits for any command started by QuickCmdSend to complete. The only argument is the poll timeout in milliseconds; 0 performs a nonblocking check. It returns the channel number of a completed command, -1 when commands are still pending but none finished before the timeout, or -2 when no quick commands remain or an error occurred.

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;
  channel1: Integer;
  channel2: Integer;
  pollTimeoutMs: Integer;
  completedChannel: Integer;
  output: string;

begin
  success := False;

  //  Demonstrates the Ssh.QuickCmdCheck method, which waits for any command started by
  //  QuickCmdSend to complete.  The only argument is the poll timeout in milliseconds; 0 performs
  //  a nonblocking check.

  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;

  //  Start two commands that will finish at different times.
  channel1 := ssh.QuickCmdSend('sleep 2; echo first done');
  if (channel1 < 0) then
    begin
      WriteLn(ssh.LastErrorText);
      Exit;
    end;

  channel2 := ssh.QuickCmdSend('echo second done');
  if (channel2 < 0) then
    begin
      WriteLn(ssh.LastErrorText);
      Exit;
    end;

  //  Collect the results as they complete.  The return value is the channel number of a completed
  //  command, -1 if commands are still pending but none finished before the timeout, or -2 when
  //  no quick commands remain (or an error occurred).
  pollTimeoutMs := 5000;
  completedChannel := ssh.QuickCmdCheck(pollTimeoutMs);
  while completedChannel <> -2 do
    begin
      if (completedChannel >= 0) then
        begin
          output := ssh.GetReceivedText(completedChannel,'utf-8');
          if (ssh.LastMethodSuccess = False) then
            begin
              WriteLn(ssh.LastErrorText);
              Exit;
            end;
          WriteLn('Channel ' + completedChannel + ' finished: ' + output);
        end;

      if (completedChannel = -1) then
        begin
          WriteLn('Still waiting for a command to finish...');
        end;

      completedChannel := ssh.QuickCmdCheck(pollTimeoutMs);
    end;

  WriteLn('All quick commands have been collected.');

  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.