(SQL Server) 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

-- Important: See this note about string length limitations for strings returned by sp_OAMethod calls.
--
CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    DECLARE @iTmp0 int
    -- Important: Do not use nvarchar(max).  See the warning about using nvarchar(max).
    DECLARE @sTmp0 nvarchar(4000)
    -- This example requires the Chilkat API to have been previously unlocked.
    -- See Global Unlock Sample for sample code.

    DECLARE @success int

    DECLARE @http int
    -- Use "Chilkat_9_5_0.Http" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.Http', @http OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    -- Set some timeouts, in seconds:
    EXEC sp_OASetProperty @http, 'ConnectTimeout', 15
    EXEC sp_OASetProperty @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.
    DECLARE @waitMaxMs int
    SELECT @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..
    DECLARE @downloadUrl nvarchar(4000)
    SELECT @downloadUrl = 'http://download.mono-project.com/archive/4.6.1/windows-installer/mono-4.6.1.5-gtksharp-2.12.38-win32-0.msi'

    DECLARE @task int
    EXEC sp_OAMethod @http, 'DownloadAsync', @task OUT, @downloadUrl, 'qa_output/mono.msi'
    EXEC sp_OAMethod @task, 'Run', @success OUT

    -- 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.
    EXEC sp_OAMethod @task, 'Wait', @success OUT, @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.
    DECLARE @wasCanceled int
    EXEC sp_OAMethod @task, 'Cancel', @wasCanceled OUT
    IF @wasCanceled = 1
      BEGIN

        PRINT 'The HTTP download took too long and was canceled.'
      END
    ELSE
      BEGIN
        -- Find out what happened.
        EXEC sp_OAGetProperty @task, 'StatusInt', @iTmp0 OUT
        IF @iTmp0 = 7
          BEGIN
            -- The task completed, which means the background thread's call to Download completed
            -- with success or failure.  Find out which...
            EXEC sp_OAMethod @task, 'GetResultBool', @success OUT
            IF @success = 1
              BEGIN

                PRINT 'Download successful!'
              END
            ELSE
              BEGIN

                PRINT 'Download failed prior to waitMaxMs...'
                EXEC sp_OAGetProperty @task, 'ResultErrorText', @sTmp0 OUT
                PRINT @sTmp0
              END
          END
        ELSE
          BEGIN
            -- The task must've been canceled or aborted by some other means..

            EXEC sp_OAGetProperty @task, 'Status', @sTmp0 OUT
            PRINT 'Task did not complete.  Final status: ' + @sTmp0
          END
      END

    EXEC @hr = sp_OADestroy @task


    EXEC @hr = sp_OADestroy @http


END
GO