SSH to a Cisco Switch - Processing "More" Responses

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Demonstrates connecting to a Cisco switch, entering privileged mode with the ena command, and running a command whose response is paged. Each page ends with --More-- and requires a SPACE character to request the next page.

Note: QuickShell allocates a PTY, which is what a network device console expects. The device presents an interactive prompt, and each command's output is read up to the next prompt.

var
success: Integer;
ssh: TChilkatSsh;
port: Integer;
password: WideString;
channelNum: Integer;
caseSensitive: Integer;
received: WideString;
enablePassword: WideString;
saMatch: TCkStringArray;
sbReceived: TChilkatStringBuilder;
moreComing: Integer;
pageText: WideString;

begin
success := 0;

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

//  Demonstrates connecting to a Cisco switch, entering privileged mode, and running a command
//  whose response is paged -- each page ends with "--More--" and requires a SPACE character to
//  request the next page.

ssh := TChilkatSsh.Create(Self);

port := 22;
success := ssh.Connect('172.16.16.100',port);
if (success = 0) then
  begin
    Memo1.Lines.Add(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 = 0) then
  begin
    Memo1.Lines.Add(ssh.LastErrorText);
    Exit;
  end;

channelNum := ssh.QuickShell();
if (channelNum < 0) then
  begin
    Memo1.Lines.Add(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 := 1;

//  In unprivileged mode the switch prompt ends with ">".
success := ssh.ChannelReceiveUntilMatch(channelNum,'>','utf-8',caseSensitive);
if (success = 0) then
  begin
    Memo1.Lines.Add(ssh.LastErrorText);
    Exit;
  end;

received := ssh.GetReceivedText(channelNum,'utf-8');
if (ssh.LastMethodSuccess = 0) then
  begin
    Memo1.Lines.Add(ssh.LastErrorText);
    Exit;
  end;
Memo1.Lines.Add(received);

//  Send "ena" to enter privileged mode.  Cisco devices expect a bare CR to terminate a command.
success := ssh.ChannelSendString(channelNum,'ena' + #13,'utf-8');
if (success = 0) then
  begin
    Memo1.Lines.Add(ssh.LastErrorText);
    Exit;
  end;

success := ssh.ChannelReceiveUntilMatch(channelNum,'Password:','utf-8',caseSensitive);
if (success = 0) then
  begin
    Memo1.Lines.Add(ssh.LastErrorText);
    Exit;
  end;

received := ssh.GetReceivedText(channelNum,'utf-8');
if (ssh.LastMethodSuccess = 0) then
  begin
    Memo1.Lines.Add(ssh.LastErrorText);
    Exit;
  end;
Memo1.Lines.Add(received);

//  The enable password is separate from the login password, and likewise should come from a
//  secure source rather than being hard-coded.
enablePassword := 'myEnablePassword';
success := ssh.ChannelSendString(channelNum,enablePassword,'utf-8');
if (success = 0) then
  begin
    Memo1.Lines.Add(ssh.LastErrorText);
    Exit;
  end;
success := ssh.ChannelSendString(channelNum,#13,'utf-8');
if (success = 0) then
  begin
    Memo1.Lines.Add(ssh.LastErrorText);
    Exit;
  end;

//  In privileged mode the prompt ends with "#" instead of ">".
success := ssh.ChannelReceiveUntilMatch(channelNum,'#','utf-8',caseSensitive);
if (success = 0) then
  begin
    Memo1.Lines.Add(ssh.LastErrorText);
    Exit;
  end;

received := ssh.GetReceivedText(channelNum,'utf-8');
if (ssh.LastMethodSuccess = 0) then
  begin
    Memo1.Lines.Add(ssh.LastErrorText);
    Exit;
  end;
Memo1.Lines.Add(received);

//  Run a command whose output is delivered a page at a time.
success := ssh.ChannelSendString(channelNum,'show running-config' + #13,'utf-8');
if (success = 0) then
  begin
    Memo1.Lines.Add(ssh.LastErrorText);
    Exit;
  end;

//  Each read ends either at the device prompt (output complete) or at "--More--" (another page
//  is waiting).  Match the full prompt rather than a bare "#", because "#" also appears inside
//  configuration text and would match too early.
saMatch := TCkStringArray.Create(Self);
saMatch.Append('MySwitchName#');
saMatch.Append('--More--');

sbReceived := TChilkatStringBuilder.Create(Self);
moreComing := 1;

while moreComing do
  begin
    success := ssh.ChannelReceiveUntilMatchN(channelNum,saMatch.ControlInterface,'utf-8',caseSensitive);
    if (success = 0) then
      begin
        Memo1.Lines.Add(ssh.LastErrorText);
        Exit;
      end;

    sbReceived.Clear();
    pageText := ssh.GetReceivedText(channelNum,'utf-8');
    if (ssh.LastMethodSuccess = 0) then
      begin
        Memo1.Lines.Add(ssh.LastErrorText);
        Exit;
      end;
    sbReceived.Append(pageText);
    Memo1.Lines.Add(pageText);

    //  If this page ended with "--More--", send a SPACE to request the next page.
    moreComing := sbReceived.Contains('--More--',caseSensitive);
    if (moreComing) then
      begin
        success := ssh.ChannelSendString(channelNum,' ','utf-8');
        if (success = 0) then
          begin
            Memo1.Lines.Add(ssh.LastErrorText);
            Exit;
          end;
      end;
  end;

ssh.Disconnect();