Perl

Cancel Async Task if not Completed after a Max Time

See more Async Examples

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. Perl

use chilkat();

$success = 0;

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

$http = chilkat::CkHttp->new();

# Set some timeouts, in seconds:
$http->put_ConnectTimeout(15);
$http->put_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.
$waitMaxMs = 2000;

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

# task is a Task
$task = $http->DownloadAsync($downloadUrl,"qa_output/mono.msi");
$task->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.
$task->Wait($waitMaxMs);

# 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.
$wasCanceled = $task->Cancel();
if ($wasCanceled == 1) {
    print "The HTTP download took too long and was canceled." . "\r\n";
}
else {
    # Find out what happened.
    if ($task->get_StatusInt() == 7) {
        # The task completed, which means the background thread's call to Download completed
        # with success or failure.  Find out which...
        $success = $task->GetResultBool();
        if ($success == 1) {
            print "Download successful!" . "\r\n";
        }
        else {
            print "Download failed prior to waitMaxMs..." . "\r\n";
            print $task->resultErrorText() . "\r\n";
        }

    }
    else {
        # The task must've been canceled or aborted by some other means..
        print "Task did not complete.  Final status: " . $task->status() . "\r\n";
    }

}