Xbase++

Async FTP Progress Info

See more FTP Examples

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

LOCAL nSuccess
LOCAL oFtp
LOCAL cLocalFilename
LOCAL cRemoteFilename
LOCAL oTask
LOCAL nCurPctDone
LOCAL cName
LOCAL cValue

nSuccess := 0

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

oFtp := CreateObject("Chilkat.Ftp2")

oFtp:Hostname := "ftp.someFtpServer.com"
nSuccess := oFtp:ConnectOnly()
IF (nSuccess != 1)
    ? oFtp:LastErrorText
    oFtp:destroy()
    RETURN
ENDIF

oFtp:Username := "myLogin"
oFtp:Password := "myPassword"
nSuccess := oFtp:LoginAfterConnectOnly()
IF (nSuccess != 1)
    ? oFtp:LastErrorText
    oFtp:destroy()
    RETURN
ENDIF

//  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.
nSuccess := oFtp:ChangeRemoteDir("someRemoteDirectory")
IF (nSuccess != 1)
    ? oFtp:LastErrorText
    oFtp:destroy()
    RETURN
ENDIF

cLocalFilename := "/temp/romeo.xml"
cRemoteFilename := "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.
oTask := oFtp:GetFileAsync(cRemoteFilename, cLocalFilename)
IF (oFtp:LastMethodSuccess == 0)
    ? oFtp:LastErrorText
    oFtp:destroy()
    RETURN
ENDIF

//  Before starting the task, tell it to keep an in-memory log of what would've been
//  ProgressInfo callbacks.
oTask:KeepProgressLog := 1

//  Schedule the task for running on the thread pool.  This changes the task's state
//  from Inert to Live.
nSuccess := oTask:Run()
IF (nSuccess != 1)
    ? oTask:LastErrorText
    oTask:destroy()
    oFtp:destroy()
    RETURN
ENDIF

//  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.
nCurPctDone := 0

DO WHILE oTask:Finished != 1

    IF (oTask:PercentDone != nCurPctDone)
        nCurPctDone := oTask:PercentDone
        ? Str(nCurPctDone) + " percent done"
    ENDIF

    //  Check the progress info log.
    //  Emit any log entries..
    DO WHILE (oTask:ProgressLogSize > 0)
        //  Get the 1st entry, emit it, and then remove it..
        cName := oTask:ProgressInfoName(0)
        cValue := oTask: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"

        ? cName + ": " + cValue
        oTask:RemoveProgressInfo(0)
    ENDDO

    //  Sleep 100 ms.
    oTask:SleepMs(100)

ENDDO

//  Just in case there are any remaining entries...
DO WHILE (oTask:ProgressLogSize > 0)
    //  Get the 1st entry, emit it, and then remove it..
    cName := oTask:ProgressInfoName(0)
    cValue := oTask:ProgressInfoValue(0)
    ? cName + ": " + cValue
    oTask:RemoveProgressInfo(0)
ENDDO

//  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 (oTask:StatusInt != 7)
    ? "Task did not complete."
    ? "task status: " + oTask:Status
    oTask:destroy()
    oFtp:destroy()
    RETURN
ENDIF

//  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.
nSuccess := oTask:GetResultBool()
IF (nSuccess != 1)
    //  The task's ResultErrorText contains what would have been in the LastErrorText property had
    //  the GetFile method been called synchronously.
    ? oTask:ResultErrorText
ELSE
    ? "File downloaded asynchronously."
ENDIF

oTask:destroy()

nSuccess := oFtp:Disconnect()

oFtp:destroy()