(Node.js) Async FTP Progress Info

Demonstrates checking for progress info updates when running a task asynchronously. This example demonstrates an FTP download.

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

var os = require('os');
if (os.platform() == 'win32') {  
    if (os.arch() == 'ia32') {
        var chilkat = require('@chilkat/ck-node21-win-ia32');
    } else {
        var chilkat = require('@chilkat/ck-node21-win64'); 
    }
} else if (os.platform() == 'linux') {
    if (os.arch() == 'arm') {
        var chilkat = require('@chilkat/ck-node21-arm');
    } else if (os.arch() == 'x86') {
        var chilkat = require('@chilkat/ck-node21-linux32');
    } else {
        var chilkat = require('@chilkat/ck-node21-linux64');
    }
} else if (os.platform() == 'darwin') {
    if (os.arch() == 'arm64') {
        var chilkat = require('@chilkat/ck-node21-mac-m1');
    } else {
        var chilkat = require('@chilkat/ck-node21-macosx');
    }
}

function chilkatExample() {

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

    var ftp = new chilkat.Ftp2();

    ftp.Hostname = "ftp.someFtpServer.com";
    var success = ftp.ConnectOnly();
    if (success !== true) {
        console.log(ftp.LastErrorText);
        return;
    }

    ftp.Username = "myLogin";
    ftp.Password = "myPassword";
    success = ftp.LoginAfterConnectOnly();
    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("someRemoteDirectory");
    if (success !== true) {
        console.log(ftp.LastErrorText);
        return;
    }

    var localFilename = "/temp/romeo.xml";
    var remoteFilename = "romeo.xml";

    // --------------------
    // Download a file
    // --------------------

    // Call the async version of the GetFile method to return a task object.
    // The task object is loaded, but is in the Inert state -- meaning it is
    // not yet scheduled to run on Chilkat's background thread pool.
    // task: Task
    var task = ftp.GetFileAsync(remoteFilename,localFilename);
    if (ftp.LastMethodSuccess == false) {
        console.log(ftp.LastErrorText);
        return;
    }

    // Before starting the task, tell it to keep an in-memory log of what would've been
    // ProgressInfo callbacks.
    task.KeepProgressLog = true;

    // Schedule the task for running on the thread pool.  This changes the task's state
    // from Inert to Live.
    success = task.Run();
    if (success !== true) {
        console.log(task.LastErrorText);

        return;
    }

    // The application is now free to do anything else
    // while the file is being downloaded.

    // For this example, we'll simply sleep and periodically
    // check to see if the download is finished, and report the progress
    // along the way.
    var curPctDone = 0;
    var name;
    var value;

    while (task.Finished !== true) {

        if (task.PercentDone !== curPctDone) {
            curPctDone = task.PercentDone;
            console.log(curPctDone + " percent done");
        }

        // Check the progress info log.
        // Emit any log entries..
        while ((task.ProgressLogSize > 0)) {
            // Get the 1st entry, emit it, and then remove it..
            name = task.ProgressInfoName(0);
            value = task.ProgressInfoValue(0);

            // Entries reporting the received byte count will have the name "RcvByteCount"
            // Entries reporting the current bytes-per-second will have the name "RcvBytesPerSec"

            console.log(name + ": " + value);
            task.RemoveProgressInfo(0);
        }

        // Sleep 100 ms.
        task.SleepMs(100);

    }

    // Just in case there are any remaining entries...
    while ((task.ProgressLogSize > 0)) {
        // Get the 1st entry, emit it, and then remove it..
        name = task.ProgressInfoName(0);
        value = task.ProgressInfoValue(0);
        console.log(name + ": " + value);
        task.RemoveProgressInfo(0);
    }

    // A finished task could be one that was canceled, aborted, or truly finished.  

    // If the task was "canceled", it was canceled prior to actually starting.  This could
    // happen if the task was canceled while waiting in a thread pool queue to be scheduled by Chilkat's
    // background thread pool scheduler.  

    // If the task was "aborted", it indicates that it was canceled while running in a background thread.  
    // The ResultErrorText will likely indicate that the task was aborted.

    // If the task "completed", then it ran to completion, but the actual success/failure of the method
    // is determined by the result obtained via a GetResult* method.  (A "completed" task will
    // have a StatusInt equal to 7.   If the task finished, but was not completed, then it must've
    // been aborted or canceled:
    if (task.StatusInt !== 7) {
        console.log("Task did not complete.");
        console.log("task status: " + task.Status);

        return;
    }

    // The GetFile method returns a boolean.  Therefore, after the task is finished,
    // we can get the boolean result by calling GetResultBool.  This is the return value had
    // we called GetFile synchronously.
    success = task.GetResultBool();
    if (success !== true) {
        // The task's ResultErrorText contains what would have been in the LastErrorText property had
        // the GetFile method been called synchronously.
        console.log(task.ResultErrorText);
    }
    else {
        console.log("File downloaded asynchronously.");
    }

    success = ftp.Disconnect();

}

chilkatExample();