(Swift 3,4,5...) Async Task Chain (another example)

Demonstrates using a task chain to run a sequence of FTP tasks asynchronously.

Chilkat Downloads for the Swift Programming Language MAC OS X (Cocoa) Objective-C/Swift Libs iOS Objective-C/Swift Libs

func chilkatTest() {
    // All Chilkat classes can be unlocked at once at the beginning of a program
    // by calling UnlockBundle.  It requires a Bundle unlock code.
    let chilkatGlob = CkoGlobal()!
    var success: Bool = chilkatGlob.unlockBundle("Anything for 30-day trial.")
    if success != true {
        print("\(chilkatGlob.lastErrorText!)")
        return
    }

    let ftp = CkoFtp2()!

    ftp.hostname = "ftp.example.com"
    ftp.username = "login"
    ftp.password = "password"

    // Connect and login to the FTP server.
    success = ftp.connect()
    if success != true {
        print("\(ftp.lastErrorText!)")
        return
    }

    let taskChain = CkoTaskChain()!

    // Create a task to change to the remote directory where the file will be uploaded.
    var task: CkoTask? = ftp.changeRemoteDirAsync("junk")
    if ftp.lastMethodSuccess == false {
        print("\(ftp.lastErrorText!)")
        return
    }

    // Add this task to the task chain.
    success = taskChain.append(task)
    task = nil

    // Create a task to upload a file.
    var localFilename: String? = "c:/temp/hamlet.xml"
    var remoteFilename: String? = "hamlet.xml"

    task = ftp.putFileAsync(localFilename, remoteFilename: remoteFilename)
    if ftp.lastMethodSuccess == false {
        print("\(ftp.lastErrorText!)")
        return
    }

    // Add this task to the task chain.
    success = taskChain.append(task)
    task = nil

    // Start the task chain running in a background thread.
    // Each task is run one after the other (on the same background thread) until all tasks have completed.
    // The task chain will stop at the first task that fails.
    taskChain.stopOnFailedTask = true
    success = taskChain.run()
    if !success {
        print("\(taskChain.lastErrorText!)")
        return
    }

    // The application is now free to do anything else
    // while the FTP commands are being run...

    // For this example, we'll simply sleep and periodically
    // check to see if the taskchain if finished. 
    while taskChain.finished != true {

        // Sleep 100 ms.
        taskChain.sleepMs(100)

    }

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

    // If the task chain "completed", then it ran to completion.  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 taskChain.statusInt.intValue != 7 {
        print("Task did not complete.")
        print("task chain status: \(taskChain.status!)")
        return
    }

    // If we got to this point, the ChangeRemoteDir and PutFile were successful.
    // We can visually verify by examining the LastErrorText that was recorded for each
    // of these method calls..
    var numTasks: Int = taskChain.numTasks.intValue
    var taskIdx: Int = 0

    while (taskIdx < numTasks) {

        task = taskChain.getTask(taskIdx)

        // Examine the status of this task, and the ResultErrorText
        // (the ResultErrorText is the ftp.LastErrorText captured for FTP method called by the task).
        // Everything should indicate success.
        print("task status: \(task!.status!)")
        print("task log: \(task!.resultErrorText!)")

        task = nil

        taskIdx = taskIdx + 1
    }

    success = ftp.disconnect()

}