Delphi DLL

SSH Quick/Simple Shell Session

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.

Background: Note that QuickShell does allocate a PTY, so the remote shell runs interactively: it prints a prompt and echoes back every command sent to it, and both the echo and the real output appear in what is received. That is what motivates the quoting trick on the final marker — writing echo THIS 'IS' THE END means the echoed command line contains the quotes while the command's actual output does not, so matching the unquoted text reliably matches the real output instead of the echo. For clean, prompt-free output, request a shell without a PTY instead.

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Delphi DLL

var
success: Boolean;
ssh: HCkSsh;
port: Integer;
password: PWideChar;
channelNum: Integer;
sbCommands: HCkStringBuilder;
commands: PWideChar;
caseSensitive: Boolean;
sessionOutput: PWideChar;

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 := CkSsh_Create();

port := 22;
success := CkSsh_Connect(ssh,'ssh.example.com',port);
if (success = False) then
  begin
    Memo1.Lines.Add(CkSsh__lastErrorText(ssh));
    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 := CkSsh_AuthenticatePw(ssh,'mySshLogin',password);
if (success = False) then
  begin
    Memo1.Lines.Add(CkSsh__lastErrorText(ssh));
    Exit;
  end;

//  Start the shell session.  A negative return value indicates failure.
channelNum := CkSsh_QuickShell(ssh);
if (channelNum < 0) then
  begin
    Memo1.Lines.Add(CkSsh__lastErrorText(ssh));
    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 := CkStringBuilder_Create();
CkStringBuilder_Append(sbCommands,'echo hello world' + #10);
CkStringBuilder_Append(sbCommands,'date' + #10);
CkStringBuilder_Append(sbCommands,'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.
CkStringBuilder_Append(sbCommands,'echo THIS ''IS'' THE END OF THE SCRIPT' + #10);

commands := CkStringBuilder__getAsString(sbCommands);
success := CkSsh_ChannelSendString(ssh,channelNum,commands,'utf-8');
if (success = False) then
  begin
    Memo1.Lines.Add(CkSsh__lastErrorText(ssh));
    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.
CkSsh_putReadTimeoutMs(ssh,15000);

caseSensitive := True;
success := CkSsh_ChannelReceiveUntilMatch(ssh,channelNum,'THIS IS THE END OF THE SCRIPT','utf-8',caseSensitive);
if (success = False) then
  begin
    Memo1.Lines.Add(CkSsh__lastErrorText(ssh));
    Exit;
  end;

//  Indicate that no more commands will be sent, then close the channel.  Close only after the
//  desired output has been received.
success := CkSsh_ChannelSendEof(ssh,channelNum);
if (success = False) then
  begin
    Memo1.Lines.Add(CkSsh__lastErrorText(ssh));
    Exit;
  end;

success := CkSsh_ChannelSendClose(ssh,channelNum);
if (success = False) then
  begin
    Memo1.Lines.Add(CkSsh__lastErrorText(ssh));
    Exit;
  end;

//  Collect any remaining output.
success := CkSsh_ChannelReceiveToClose(ssh,channelNum);
if (success = False) then
  begin
    Memo1.Lines.Add(CkSsh__lastErrorText(ssh));
    Exit;
  end;

sessionOutput := CkSsh__getReceivedText(ssh,channelNum,'utf-8');
if (CkSsh_getLastMethodSuccess(ssh) = False) then
  begin
    Memo1.Lines.Add(CkSsh__lastErrorText(ssh));
    Exit;
  end;
Memo1.Lines.Add('--- output ----');
Memo1.Lines.Add(sessionOutput);

CkSsh_Disconnect(ssh);

CkSsh_Dispose(ssh);
CkStringBuilder_Dispose(sbCommands);