Receive from an SSH Channel Until a Pattern Matches

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Demonstrates the Chilkat Ssh.ChannelReceiveUntilMatch method, which receives text until the accumulated text matches a pattern. The arguments are the channel number, the pattern, the charset, and whether matching is case-sensitive. Existing buffered text is checked before waiting for more network data.

Important: Set the ReadTimeoutMs property before calling this method. It defaults to 0, meaning no limit, so without it the call waits forever if the received data never contains a match.

var
success: Boolean;
ssh: HCkSsh;
sshPort: Integer;
password: PWideChar;
channelNum: Integer;
caseSensitive: Boolean;
output: PWideChar;

begin
success := False;

//  Demonstrates the Ssh.ChannelReceiveUntilMatch method, which receives text until the
//  accumulated text matches a pattern.  The 1st argument is the channel number, the 2nd is the
//  pattern, the 3rd is the charset, and the 4th selects case-sensitive matching.  The pattern
//  supports literal characters plus "*", which matches zero or more characters.

ssh := CkSsh_Create();

sshPort := 22;
success := CkSsh_Connect(ssh,'ssh.example.com',sshPort);
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;

channelNum := CkSsh_OpenSessionChannel(ssh);
if (channelNum < 0) then
  begin
    Memo1.Lines.Add(CkSsh__lastErrorText(ssh));
    Exit;
  end;

//  Start a shell WITHOUT requesting a PTY.  Without a PTY the shell sees it is connected to a
//  raw data pipe and enters non-interactive mode: it suppresses the command prompt, does not
//  echo typed commands back, and skips interactive login scripts.  The output is therefore
//  clean and easily parseable -- but because no prompt is ever sent, code must not wait for
//  one.  Instead, have each command print a predictable marker, or wait for EOF / channel close.
success := CkSsh_SendReqShell(ssh,channelNum);
if (success = False) then
  begin
    Memo1.Lines.Add(CkSsh__lastErrorText(ssh));
    Exit;
  end;

//  There is no prompt to wait for, so make the command itself announce when it has finished
//  by echoing a marker after it.
success := CkSsh_ChannelSendString(ssh,channelNum,'ls -l /tmp; echo DONE_MARKER' + #10,'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);

//  Receive until the marker appears in the output.
caseSensitive := False;
success := CkSsh_ChannelReceiveUntilMatch(ssh,channelNum,'DONE_MARKER','utf-8',caseSensitive);
if (success = False) then
  begin
    Memo1.Lines.Add(CkSsh__lastErrorText(ssh));
    Exit;
  end;

output := 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);

CkSsh_Disconnect(ssh);

CkSsh_Dispose(ssh);