PowerBuilder

Cancel HTTP Get Async Task if not Completed after a Max Time

See more HTTP 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. PowerBuilder

integer li_rc
integer li_Success
oleobject loo_Http
string ls_Url
oleobject loo_Task
integer li_WaitMaxMs
integer li_WasCanceled
string ls_ResponseStr

li_Success = 0

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

loo_Http = create oleobject
li_rc = loo_Http.ConnectToNewObject("Chilkat.Http")
if li_rc < 0 then
    destroy loo_Http
    MessageBox("Error","Connecting to COM object failed")
    return
end if

// Set some timeouts, in seconds:
loo_Http.ConnectTimeout = 15
// ReadTimeout specifies the max number of seconds that must elapse when no additional data is received before
// timing out.  For example, if a server sends a 300 byte response at the rate of 1 byte per second, then
// ReadTimeout would never cause a timeout because there is never a 15 second interval when nothing arrives.
loo_Http.ReadTimeout = 15

ls_Url = "https://your-url.com/something"
loo_Task = loo_Http.QuickGetStrAsync(ls_Url)
loo_Task.Run()

// Wait a maximum of waitMaxMs for the task (i.e. the HTTP GET) to complete.
// The Wait method returns when the task has been canceled, aborted, or completed, or when the max allotted time has passed.
li_WaitMaxMs = 20000
loo_Task.Wait(li_WaitMaxMs)

// At this point, the GET 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.
li_WasCanceled = loo_Task.Cancel()
if li_WasCanceled = 1 then
    Write-Debug "The HTTP GET took too long and was canceled."
else
    // Find out what happened.
    if loo_Task.StatusInt = 7 then
        // The task completed, which means the background thread's call to QuickGetStr completed
        // with success or failure.  Find out which...
        if loo_Task.TaskSuccess = 1 then
            // Get the string response for the call to QuickGetStr (which happened in Chilkat's background thread).
            ls_ResponseStr = loo_Task.GetResultString()
            Write-Debug ls_ResponseStr
            Write-Debug "HTTP GET successful!"
        else
            Write-Debug "HTTP GET failed prior to waitMaxMs..."
            Write-Debug loo_Task.ResultErrorText
        end if

    else
        // The task must've been canceled or aborted by some other means..
        Write-Debug "Task did not complete.  Final status: " + loo_Task.Status
    end if

end if

destroy loo_Task


destroy loo_Http