React Native

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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import { SFtp } from '@chilkat/react-native'

async function chilkatExample() {
  // 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.

  const sftp = new SFtp();

  // Step 1: Connect the SSH transport.  Port 22 is the usual port.
  const port = 22;
  try {
    await sftp.connectAsync('sftp.example.com', port);
  } catch {
    console.log(sftp.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.
  const password = 'mySshPassword';

  try {
    await sftp.authenticatePwAsync('mySshLogin', password);
  } catch {
    console.log(sftp.lastErrorText);
    return;
  }

  // Step 3: Open the SFTP subsystem.  This must be done after authentication and before any
  // file or directory operations.
  try {
    await sftp.initializeSftpAsync();
  } catch {
    console.log(sftp.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.
  let homeDir: string;
  try {
    homeDir = await sftp.realPathAsync('.', '');
  } catch {
    console.log(sftp.lastErrorText);
    return;
  }

  console.log(`Home directory: ${homeDir}`);

  // Canonicalize a relative path with "..", resolving it to an absolute path.
  let resolved: string;
  try {
    resolved = await sftp.realPathAsync('subdir/../otherdir', '');
  } catch {
    console.log(sftp.lastErrorText);
    return;
  }

  console.log(`Resolved path: ${resolved}`);

  sftp.disconnect();
}