Android™

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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// Important: Don't forget to include the call to System.loadLibrary
// as shown at the bottom of this code sample.
package com.test;

import android.app.Activity;
import com.chilkatsoft.*;

import android.widget.TextView;
import android.os.Bundle;

public class SimpleActivity extends Activity {

  private static final String TAG = "Chilkat";

  // Called when the activity is first created.
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    boolean success = false;

    //  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.

    CkSFtp sftp = new CkSFtp();

    //  Step 1: Connect the SSH transport.  Port 22 is the usual port.
    int port = 22;
    success = sftp.Connect("sftp.example.com",port);
    if (success == false) {
        Log.i(TAG, 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.
    String password = "mySshPassword";

    success = sftp.AuthenticatePw("mySshLogin",password);
    if (success == false) {
        Log.i(TAG, sftp.lastErrorText());
        return;
        }

    //  Step 3: Open the SFTP subsystem.  This must be done after authentication and before any
    //  file or directory operations.
    success = sftp.InitializeSftp();
    if (success == false) {
        Log.i(TAG, 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.
    String homeDir = sftp.realPath(".","");
    if (sftp.get_LastMethodSuccess() == false) {
        Log.i(TAG, sftp.lastErrorText());
        return;
        }

    Log.i(TAG, "Home directory: " + homeDir);

    //  Canonicalize a relative path with "..", resolving it to an absolute path.
    String resolved = sftp.realPath("subdir/../otherdir","");
    if (sftp.get_LastMethodSuccess() == false) {
        Log.i(TAG, sftp.lastErrorText());
        return;
        }

    Log.i(TAG, "Resolved path: " + resolved);

    sftp.Disconnect();

  }

  static {
      System.loadLibrary("chilkat");

      // Note: If the incorrect library name is passed to System.loadLibrary,
      // then you will see the following error message at application startup:
      //"The application <your-application-name> has stopped unexpectedly. Please try again."
  }
}