Dart

Open an SSH Session Channel

Demonstrates the Chilkat Ssh.OpenSessionChannel method, which opens a new SSH session channel. It takes no arguments and returns the channel number, or -1 on failure. The transport must already be connected and authenticated.

Background: SSH multiplexes independent channels over one authenticated connection, and a session channel is the one used to run a command, start a shell, or invoke a subsystem. Opening the channel is only the container — nothing runs until you follow it with an exec, shell, or subsystem request. Always test for a negative return rather than assuming success.

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Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // Demonstrates the Ssh.OpenSessionChannel method, which opens a new SSH session channel.  It
  // takes no arguments and returns the channel number, or -1 on failure.  The transport must
  // already be connected and authenticated.

  final ssh = CkSsh();

  final sshPort = 22;
  try {
    ssh.connect('ssh.example.com', sshPort);
  } 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 {
    ssh.authenticatePw('mySshLogin', password);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Open a session channel.  A negative return value indicates failure.
  final channelNum = ssh.openSessionChannel();
  if (channelNum < 0) {
    print(ssh.lastErrorText);
    return;
  }

  print('Opened session channel: $channelNum');

  // Opening the channel does not start a shell or command -- send an exec, shell, or subsystem
  // request next.

  ssh.disconnect();
}