SSH Quick/Simple Shell Session

See more SSH Examples

Demonstrates the simplified way to run multiple commands in a shell session using QuickShell, which combines OpenSessionChannel, SendReqPty, and SendReqShell into one call. The commands are built in a StringBuilder, sent together, and the output is read up to a marker echoed by the final command.

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,
  Chilkat.StringBuilder;

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

procedure RunDemo;
var
  success: Boolean;
  ssh: TSsh;
  port: Integer;
  password: string;
  channelNum: Integer;
  sbCommands: TStringBuilder;
  commands: string;
  caseSensitive: Boolean;
  sessionOutput: string;

begin
  success := False;

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

  //  Demonstrates the simplified way to run multiple commands in a shell session using QuickShell.
  //  
  //  Note: QuickShell internally does OpenSessionChannel, SendReqPty, and SendReqShell, so it DOES
  //  allocate a pseudo-terminal.  The remote shell therefore runs interactively: it prints a
  //  command prompt and echoes back the commands that are sent to it.  Both the echoed input and
  //  the real output appear in what is received.

  ssh := TSsh.Create;

  port := 22;
  success := ssh.Connect('ssh.example.com',port);
  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 the shell session.  A negative return value indicates failure.
  channelNum := ssh.QuickShell();
  if (channelNum < 0) then
    begin
      WriteLn(ssh.LastErrorText);
      Exit;
    end;

  //  Build the commands, one per line.  Line endings matter: Unix/Linux servers typically expect
  //  a bare LF, while Windows servers may require CRLF.
  sbCommands := TStringBuilder.Create;
  sbCommands.Append('echo hello world' + #10);
  sbCommands.Append('date' + #10);
  sbCommands.Append('df' + #10);

  //  The final command echoes a marker used to detect the end of the output.  The single quotes
  //  around 'IS' are a trick: the terminal echo of the typed command includes the quotes, while
  //  the command's actual output does not.  Matching the unquoted form therefore matches the real
  //  output rather than the echo.
  sbCommands.Append('echo THIS ''IS'' THE END OF THE SCRIPT' + #10);

  commands := sbCommands.GetAsString();
  success := ssh.ChannelSendString(channelNum,commands,'utf-8');
  if (success = False) then
    begin
      WriteLn(ssh.LastErrorText);
      Exit;
    end;

  //  IMPORTANT: Set a read timeout before receiving until a match.  ReadTimeoutMs defaults to 0,
  //  which means no limit -- without it, this call waits forever if the received data never
  //  contains a match.
  ssh.ReadTimeoutMs := 15000;

  caseSensitive := True;
  success := ssh.ChannelReceiveUntilMatch(channelNum,'THIS IS THE END OF THE SCRIPT','utf-8',caseSensitive);
  if (success = False) then
    begin
      WriteLn(ssh.LastErrorText);
      Exit;
    end;

  //  Indicate that no more commands will be sent, then close the channel.  Close only after the
  //  desired output has been received.
  success := ssh.ChannelSendEof(channelNum);
  if (success = False) then
    begin
      WriteLn(ssh.LastErrorText);
      Exit;
    end;

  success := ssh.ChannelSendClose(channelNum);
  if (success = False) then
    begin
      WriteLn(ssh.LastErrorText);
      Exit;
    end;

  //  Collect any remaining output.
  success := ssh.ChannelReceiveToClose(channelNum);
  if (success = False) then
    begin
      WriteLn(ssh.LastErrorText);
      Exit;
    end;

  sessionOutput := ssh.GetReceivedText(channelNum,'utf-8');
  if (ssh.LastMethodSuccess = False) then
    begin
      WriteLn(ssh.LastErrorText);
      Exit;
    end;
  WriteLn('--- output ----');
  WriteLn(sessionOutput);

  ssh.Disconnect();


  ssh.Free;
  sbCommands.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.