Dart

Get the Type of an Active SSH Channel

Demonstrates the Chilkat Ssh.GetChannelType method, which returns the type of the channel at a zero-based enumeration index. The only argument is the index — an enumeration position, not a channel number. Values include session, x11, forwarded-tcpip, and direct-tcpip.

Background: Paired with GetChannelNumber, this turns the channel collection into a readable inventory of what a connection is currently doing — which channels are running commands (session) versus tunneling TCP traffic (direct-tcpip). That is valuable for diagnostics and for application code that manages several channel kinds at once. An out-of-range index causes the string-returning method to report failure.

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Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // Demonstrates the Ssh.GetChannelType method, which returns the type of the channel at a
  // zero-based enumeration index.  The only argument is the index, which is an enumeration
  // position and not a channel number.  Values include "session" and "direct-tcpip".

  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;
  }

  final channelNum = ssh.openSessionChannel();
  if (channelNum < 0) {
    print(ssh.lastErrorText);
    return;
  }

  // Enumerate the active channels and report each one's number and type.
  final n = ssh.numOpenChannels;
  for (var i = 0; i < n; i++) {
    final chNum = ssh.getChannelNumber(i);
    final String chType;
    try {
      chType = ssh.getChannelType(i);
    } on ChilkatException catch (e) {
      print(e.lastErrorText);
      return;
    }

    print('Channel $chNum is of type $chType');
  }

  ssh.disconnect();
}