Dart

Send an SSH IGNORE Message over SFTP

Demonstrates the Chilkat SFtp.SendIgnore method, which sends an SSH IGNORE message. It takes no arguments. The server sends no reply, but a successful send helps confirm the connection is still writable. No SFTP file handle is required.

Background: The SSH IGNORE message is discarded by the peer by design; its value is as a lightweight keep-alive or liveness probe. During a long-idle SFTP session — for instance while waiting between scheduled transfers — a periodic SendIgnore both keeps the connection from being dropped for inactivity and proves the link is still usable, without touching any file.

Chilkat Dart Downloads

Download Chilkat for Dart

Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // Demonstrates the SFtp.SendIgnore method, which sends an SSH IGNORE message.  It takes no
  // arguments.  The server sends no reply, but a successful send helps confirm the connection is
  // still writable.  No SFTP file handle is required.

  final sftp = CkSFtp();

  // Step 1: Connect the SSH transport.  Port 22 is the usual port.
  final port = 22;
  try {
    sftp.connect('sftp.example.com', port);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // 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.
  final password = 'mySshPassword';

  try {
    sftp.authenticatePw('mySshLogin', password);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Step 3: Open the SFTP subsystem.  This must be done after authentication and before any
  // file or directory operations.
  try {
    sftp.initializeSftp();
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Send an IGNORE message to verify the connection is still writable.
  try {
    sftp.sendIgnore();
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('IGNORE message sent.');

  sftp.disconnect();
}