(Go) Async SFTP Progress Info

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

Chilkat Go Downloads Go Package for Windows, MacOS, Linux, Alpine Linux, Solaris

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

    sftp := chilkat.NewSFtp()

    // Set some timeouts, in milliseconds:
    sftp.SetConnectTimeoutMs(15000)
    sftp.SetIdleTimeoutMs(15000)

    // Connect to the SFTP server.  
    success := sftp.Connect("sftp.example.com",22)
    if success != true {
        fmt.Println(sftp.LastErrorText())
        sftp.DisposeSFtp()
        return
    }

    // Authenticate with the SSH server.  Chilkat SFTP supports
    // both password-based authenication as well as public-key
    // authentication.  This example uses password authenication.
    success = sftp.AuthenticatePw("myLogin","myPassword")
    if success != true {
        fmt.Println(sftp.LastErrorText())
        sftp.DisposeSFtp()
        return
    }

    // After authenticating, the SFTP subsystem must be initialized:
    success = sftp.InitializeSftp()
    if success != true {
        fmt.Println(sftp.LastErrorText())
        sftp.DisposeSFtp()
        return
    }

    // --------------------
    // Download a file
    // --------------------
    localFilePath := "c:/temp/hamlet.xml"
    remoteFilePath := "subdir1/subdir2/hamlet.xml"

    // Call the async version of the DownloadFileByName 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.
    c := make(chan *chilkat.Task)
    go sftp.DownloadFileByNameAsync(remoteFilePath,localFilePath,c)
    task := <-c
    if sftp.LastMethodSuccess() == false {
        fmt.Println(sftp.LastErrorText())
        sftp.DisposeSFtp()
        task.DisposeTask()
        return
    }

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

    // Schedule the task for running on the thread pool.  This changes the task's state
    // from Inert to Live.

    if success != true {
        fmt.Println(task.LastErrorText())
        task.DisposeTask()
        sftp.DisposeSFtp()
        task.DisposeTask()
        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.
    curPctDone := 0
    var name *string = new(string)
    var value *string = new(string)

    for task.Finished() != true {

        if task.PercentDone() != curPctDone {
            curPctDone = task.PercentDone()
            fmt.Println(curPctDone, " percent done")
        }

        // Check the progress info log.
        // Emit any log entries..
        for (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"

            fmt.Println(*name, ": ", *value)
            task.RemoveProgressInfo(0)
        }

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

    }

    // Just in case there are any remaining entries...
    for (task.ProgressLogSize() > 0) {
        // Get the 1st entry, emit it, and then remove it..
        name = task.ProgressInfoName(0)
        value = task.ProgressInfoValue(0)
        fmt.Println(*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 {
        fmt.Println("Task did not complete.")
        fmt.Println("task status: ", task.Status())
        task.DisposeTask()
        sftp.DisposeSFtp()
        task.DisposeTask()
        return
    }

    // The DownloadFileByName 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 DownloadFileByName synchronously.
    success = task.GetResultBool()
    if success != true {
        // The task's ResultErrorText contains what would have been in the LastErrorText property had
        // the DownloadFileByName method been called synchronously.
        fmt.Println(task.ResultErrorText())
    } else {
        fmt.Println("File downloaded asynchronously.")
    }

    task.DisposeTask()

    sftp.DisposeSFtp()
    task.DisposeTask()