(Visual FoxPro) Cancel Async Task if not Completed after a Max Time

Demonstrates how to wait a maximum amount of time for an asynchronous task to completed. If not completed in the allotted amount of time, the task is cancelled.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

LOCAL lnSuccess
LOCAL loHttp
LOCAL lnWaitMaxMs
LOCAL lcDownloadUrl
LOCAL loTask
LOCAL lnWasCanceled

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

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Http')
loHttp = CreateObject('Chilkat.Http')

* Set some timeouts, in seconds:
loHttp.ConnectTimeout = 15
loHttp.ReadTimeout = 15

* Wait a max time of 2 seconds for the task.
* In this example, it's an unreasonably small amount of time,
* which means the task will get cancelled.
lnWaitMaxMs = 2000

* We're just going to download for 2 seconds and then cancel.
* Substitute your own URL with a large enough file for testing..
lcDownloadUrl = "http://download.mono-project.com/archive/4.6.1/windows-installer/mono-4.6.1.5-gtksharp-2.12.38-win32-0.msi"

loTask = loHttp.DownloadAsync(lcDownloadUrl,"qa_output/mono.msi")
loTask.Run()

* Wait a maximum of waitMaxMs for the task (i.e. the HTTP download) to complete.
* The Wait method returns when the task has been canceled, aborted, or completed, or when the max allotted time has passed.
loTask.Wait(lnWaitMaxMs)

* At this point, the download may or may not have completed.  
* Rather than checking the Task status, we can call task.Cancel because
* if the Task is no longer running (because it already completed, was canceled or aborted), then the 
* call to Cancel is a NO-OP (meaning it does nothing and the Task's status is unaffected).
* Also, task.Cancel returns 1 if the task was in the "queued" or "running" state and was canceled or aborted. 
* The method returns 0 if the task has any other status.
lnWasCanceled = loTask.Cancel()
IF (lnWasCanceled = 1) THEN
    ? "The HTTP download took too long and was canceled."
ELSE
    * Find out what happened.
    IF (loTask.StatusInt = 7) THEN
        * The task completed, which means the background thread's call to Download completed
        * with success or failure.  Find out which...
        lnSuccess = loTask.GetResultBool()
        IF (lnSuccess = 1) THEN
            ? "Download successful!"
        ELSE
            ? "Download failed prior to waitMaxMs..."
            ? loTask.ResultErrorText
        ENDIF

    ELSE
        * The task must've been canceled or aborted by some other means..
        ? "Task did not complete.  Final status: " + loTask.Status
    ENDIF

ENDIF

RELEASE loTask

RELEASE loHttp