PowerShell

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. PowerShell

Add-Type -Path "C:\chilkat\ChilkatDotNet47-x64\ChilkatDotNet47.dll"

$success = $false

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

$http = New-Object Chilkat.Http

# Set some timeouts, in seconds:
$http.ConnectTimeout = 15
$http.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 = $http.DownloadAsync($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 $true if the task was in the "queued" or "running" state and was canceled or aborted. 
# The method returns $false if the task has any other status.
$wasCanceled = $task.Cancel()
if ($wasCanceled -eq $true) {
    $("The HTTP download took too long and was canceled.")
}
else {
    # Find out what happened.
    if ($task.StatusInt -eq 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 -eq $true) {
            $("Download successful!")
        }
        else {
            $("Download failed prior to waitMaxMs...")
            $($task.ResultErrorText)
        }

    }
    else {
        # The task must've been canceled or aborted by some other means..
        $("Task did not complete.  Final status: " + $task.Status)
    }

}