Dart

Resolve an Absolute Remote Path with SFTP RealPath

Demonstrates the Chilkat SFtp.RealPath method, which asks the server to canonicalize a path and returns the resulting absolute remote path. The first argument is the original path and the second is an optional compose path (SFTP v5 or later); pass an empty string when no composition is needed.

Background: The server — not the client — owns the remote filesystem's layout, so path canonicalization must happen on the server. RealPath resolves ., .., and symbolic links into a single absolute path, which is the reliable way to learn the session's home directory (canonicalize .) or to turn a relative path into an absolute one before storing or displaying it. On SFTP v5 and later, the compose path can additionally join or override the original.

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Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // Demonstrates the SFtp.RealPath method, which asks the server to canonicalize a path and
  // returns the resulting absolute remote path.  The 1st argument is the original path and the
  // 2nd is an optional compose path (SFTP v5+), which may be an empty string.

  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;
  }

  // Resolve "." to the absolute path of the session's default (home) directory.  No compose path
  // is needed, so the 2nd argument is an empty string.
  final String homeDir;
  try {
    homeDir = sftp.realPath('.', '');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('Home directory: $homeDir');

  // Canonicalize a relative path with "..", resolving it to an absolute path.
  final String resolved;
  try {
    resolved = sftp.realPath('subdir/../otherdir', '');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('Resolved path: $resolved');

  sftp.disconnect();
}