React Native

ProgressMonSize Property

Demonstrates the case where the ProgressMonSize property is required to monitor the progress of FTP downloads.

When a file is downloaded, most FTP servers will indicate the file size in the intermediate "150" response. For example:

RETR hamlet.xml
150 Opening BINARY mode data connection for hamlet.xml (279658 Bytes).
226 Transfer complete.

However, some FTP servers do not provide the file size. For example, from a FileZilla server:

RETR files.txt
150 Connection accepted
226 Transfer OK

If the file size is not present, the component does not know how many bytes are forthcoming, and therefore it is not possible to monitor percentage completion progress -- unless the application provides a little help by setting the ProgressMonSize property just prior to calling GetFile.

The application should set the ProgressMonSize to the size indicated by GetSizeByName as demonstrated in this example.

React Native

import { Ftp2 } from '@chilkat/react-native'

async function chilkatExample() {
  // This example requires the Chilkat API to have been previously unlocked.
  // See Global Unlock Sample for sample code.

  const ftp = new Ftp2();

  // Called with the percent completed (0..100) while an ...Async method runs.
  ftp.onPercentDone = (pctDone) => {
    console.log(`Percent Done: ${pctDone}`);
  };
  ftp.onProgressInfo = (name, value) => {
    console.log(`${name}: ${value}`);
  };

  ftp.hostname = 'ftp.example.com';
  ftp.username = 'login';
  ftp.password = 'password';

  ftp.keepSessionLog = true;

  // Connect and login to the FTP server.
  try {
    await ftp.connectAsync();
  } catch {
    console.log(ftp.lastErrorText);
    return;
  }

  // Change to the remote directory where the file is located.
  // This step is only necessary if the file is not in the root directory
  // for the FTP account.
  try {
    await ftp.changeRemoteDirAsync('junk');
  } catch {
    console.log(ftp.lastErrorText);
    return;
  }

  // Download a file.
  const localFilename = 'hamlet.xml';
  const remoteFilename = 'hamlet.xml';

  // If the FTP server does not supply the file size in the "150"
  // intermediate response (to the RETR command), then tell
  // the component how many bytes are forthcoming (if your
  // application wishes to monitor the progress as a percentage
  // completion).
  const fileSize = await ftp.getSizeByNameAsync(remoteFilename);
  ftp.progressMonSize = fileSize;

  try {
    await ftp.getFileAsync(remoteFilename, localFilename);
  } catch {
    console.log(ftp.lastErrorText);
    return;
  }

  console.log(ftp.sessionLog);

  await ftp.disconnectAsync();
}