(Node.js) Restart/Resume FTP Download

Resume downloading a file from an FTP server.

Install Chilkat for Node.js and Electron using npm at Chilkat npm packages for Node.js Chilkat npm packages for Electron on Windows, Linux, MacOS

var os = require('os');
if (os.platform() == 'win32') {  
  var chilkat = require('@chilkat/ck-node23-win64'); 
} else if (os.platform() == 'linux') {
    if (os.arch() == 'arm') {
        var chilkat = require('@chilkat/ck-node23-linux-arm');
    } else if (os.arch() == 'arm64') {
        var chilkat = require('@chilkat/ck-node23-linux-arm64');
    } else {
        var chilkat = require('@chilkat/ck-node23-linux-x64');
    }
} else if (os.platform() == 'darwin') {
  var chilkat = require('@chilkat/ck-node23-mac-universal');
}

function chilkatExample() {

    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    var ftp = new chilkat.Ftp2();

    ftp.Hostname = "ftp.example.com";
    ftp.Username = "login";
    ftp.Password = "password";

    // Connect and login to the FTP server.
    var success = ftp.Connect();
    if (success !== true) {
        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.
    success = ftp.ChangeRemoteDir("temp");
    if (success !== true) {
        console.log(ftp.LastErrorText);
        return;
    }

    // To resume a download, it is assumed that the partial file
    // is already present on the local filesystem.
    // You only need to set the RestartNext property to resume
    // the download.  The Chilkat FTP component sets the resume
    // point by getting the existing size of the target (local) file.
    ftp.RestartNext = true;

    var localFilename = "big.zip";
    var remoteFilename = "big.zip";

    // Resume downloading...
    success = ftp.GetFile(remoteFilename,localFilename);
    if (success !== true) {
        console.log(ftp.LastErrorText);
        return;
    }

    success = ftp.Disconnect();

    console.log("File Downloaded!");

}

chilkatExample();