Dart

Close a Remote SFTP File or Directory Handle

Demonstrates the Chilkat SFtp.CloseHandle method, which closes a remote file or directory handle previously returned by OpenFile or OpenDir. The only argument is the handle.

Background: Every opened handle corresponds to state the server holds, and servers cap how many a session may keep open at once, so a long-running program that forgets to close handles will eventually start failing to open new ones. Closing also ensures buffered writes are committed. Once closed, a handle is invalid and must not be reused.

Chilkat Dart Downloads

Download Chilkat for Dart

Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // Demonstrates the SFtp.CloseHandle method, which closes a remote file or directory handle.  The
  // only argument is the handle returned by OpenFile or OpenDir.

  final sftp = CkSFtp();

  // Connect, authenticate, and initialize the SFTP subsystem.
  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;
  }

  try {
    sftp.initializeSftp();
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Open a remote file, obtaining a handle.
  final String handle;
  try {
    handle = sftp.openFile('subdir/data.txt', 'readOnly', 'openExisting');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // ... use the handle ...

  // Close the handle to release the server-side resource.  A handle should not be used after it
  // is closed.
  try {
    sftp.closeHandle(handle);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('Handle closed.');

  sftp.disconnect();
}