Delphi ActiveX

Check Whether SSH Channel EOF Was Received

Demonstrates the Chilkat Ssh.ChannelReceivedEof method, which reports whether an SSH EOF message has been received for a channel. The only argument is the channel number. EOF means the server will send no more ordinary channel data, but it does not close the channel.

Background: EOF and CLOSE are separate events, and the distinction matters when deciding whether a command has truly finished. A server commonly sends EOF first and CLOSE afterward; in that interval this method is true while ChannelReceivedClose is still false, and the channel remains open and counted. EOF is the signal that all output has been produced — useful when you want to stop reading without waiting for the full close handshake. It returns false for an invalid, released, or locally closed channel.

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var
success: Integer;
ssh: TChilkatSsh;
sshPort: Integer;
password: WideString;
channelNum: Integer;

begin
success := 0;

//  Demonstrates the Ssh.ChannelReceivedEof method, which reports whether an SSH EOF message has
//  been received for a channel.  The only argument is the channel number.  EOF means the server
//  will send no more ordinary channel data, but it does not close the channel.

ssh := TChilkatSsh.Create(Self);

sshPort := 22;
success := ssh.Connect('ssh.example.com',sshPort);
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.OpenSessionChannel();
if (channelNum < 0) then
  begin
    Memo1.Lines.Add(ssh.LastErrorText);
    Exit;
  end;

success := ssh.SendReqExec(channelNum,'ls -l /tmp');
if (success = 0) then
  begin
    Memo1.Lines.Add(ssh.LastErrorText);
    Exit;
  end;

//  IMPORTANT: Set a read timeout.  ReadTimeoutMs defaults to 0, which means no limit -- without
//  it, this call waits forever if the server never sends channel close.
ssh.ReadTimeoutMs := 15000;

success := ssh.ChannelReceiveToClose(channelNum);
if (success = 0) then
  begin
    Memo1.Lines.Add(ssh.LastErrorText);
    Exit;
  end;

if (ssh.ChannelReceivedEof(channelNum)) then
  begin
    Memo1.Lines.Add('EOF was received -- no more ordinary channel data will arrive.');
  end
else
  begin
    Memo1.Lines.Add('No EOF has been received.');
  end;

ssh.Disconnect();