Android™

Read Text from a Remote SFTP File (Sequential)

Demonstrates the Chilkat SFtp.ReadFileText method, which reads up to a number of bytes from the current position of an open handle and decodes them to text. The arguments are the handle, the maximum number of bytes, and the charset. This example reads in chunks until end-of-file.

Background: Reading a file in bounded chunks keeps memory use predictable regardless of file size, which is why the loop reads a fixed amount and repeats until Eof. A subtlety worth knowing: the byte limit is applied to the encoded bytes, so a chunk boundary could in principle fall in the middle of a multibyte character — accumulating the pieces and decoding the whole avoids any such issue in practice here since the text is reassembled in a StringBuilder.

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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.ReadFileText method, which reads up to a number of bytes from the current
    //  position of an open handle and decodes them to text.  The 1st argument is the handle, the 2nd
    //  is the maximum number of bytes, and the 3rd is the charset.

    CkSFtp sftp = new CkSFtp();

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

    success = sftp.InitializeSftp();
    if (success == false) {
        Log.i(TAG, sftp.lastErrorText());
        return;
        }

    //  Open the remote file for reading.
    String handle = sftp.openFile("subdir/notes.txt","readOnly","openExisting");
    if (sftp.get_LastMethodSuccess() == false) {
        Log.i(TAG, sftp.lastErrorText());
        return;
        }

    //  Read the file in chunks until end-of-file, accumulating the text.
    CkStringBuilder sbContent = new CkStringBuilder();
    int chunkSize = 4096;
    boolean reading = true;
    while (reading) {
        String chunk = sftp.readFileText(handle,chunkSize,"utf-8");
        if (sftp.LastReadFailed(handle)) {
            Log.i(TAG, sftp.lastErrorText());
            return;
            }

        sbContent.Append(chunk);

        //  Stop once the end of the file has been reached.
        reading = !sftp.Eof(handle);
        }

    success = sftp.CloseHandle(handle);
    if (success == false) {
        Log.i(TAG, sftp.lastErrorText());
        return;
        }

    Log.i(TAG, sbContent.getAsString());

    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."
  }
}