(SQL Server) Async Task Chain (another example)

Demonstrates using a task chain to run a sequence of FTP tasks asynchronously.

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
    DECLARE @sTmp0 nvarchar(4000)
    -- All Chilkat classes can be unlocked at once at the beginning of a program
    -- by calling UnlockBundle.  It requires a Bundle unlock code.
    DECLARE @chilkatGlob int
    EXEC @hr = sp_OACreate 'Chilkat_9_5_0.Global', @chilkatGlob OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    DECLARE @success int
    EXEC sp_OAMethod @chilkatGlob, 'UnlockBundle', @success OUT, 'Anything for 30-day trial.'
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @chilkatGlob, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @chilkatGlob
        RETURN
      END

    DECLARE @ftp int
    EXEC @hr = sp_OACreate 'Chilkat_9_5_0.Ftp2', @ftp OUT

    EXEC sp_OASetProperty @ftp, 'Hostname', 'ftp.example.com'
    EXEC sp_OASetProperty @ftp, 'Username', 'login'
    EXEC sp_OASetProperty @ftp, 'Password', 'password'

    -- Connect and login to the FTP server.
    EXEC sp_OAMethod @ftp, 'Connect', @success OUT
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @ftp, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @chilkatGlob
        EXEC @hr = sp_OADestroy @ftp
        RETURN
      END

    DECLARE @taskChain int
    EXEC @hr = sp_OACreate 'Chilkat_9_5_0.TaskChain', @taskChain OUT

    -- Create a task to change to the remote directory where the file will be uploaded.
    DECLARE @task int
    EXEC sp_OAMethod @ftp, 'ChangeRemoteDirAsync', @task OUT, 'junk'
    EXEC sp_OAGetProperty @ftp, 'LastMethodSuccess', @iTmp0 OUT
    IF @iTmp0 = 0
      BEGIN
        EXEC sp_OAGetProperty @ftp, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @chilkatGlob
        EXEC @hr = sp_OADestroy @ftp
        EXEC @hr = sp_OADestroy @taskChain
        RETURN
      END
    -- Add this task to the task chain.
    EXEC sp_OAMethod @taskChain, 'Append', @success OUT, @task
    EXEC @hr = sp_OADestroy @task

    -- Create a task to upload a file.
    DECLARE @localFilename nvarchar(4000)
    SELECT @localFilename = 'c:/temp/hamlet.xml'
    DECLARE @remoteFilename nvarchar(4000)
    SELECT @remoteFilename = 'hamlet.xml'

    EXEC sp_OAMethod @ftp, 'PutFileAsync', @task OUT, @localFilename, @remoteFilename
    EXEC sp_OAGetProperty @ftp, 'LastMethodSuccess', @iTmp0 OUT
    IF @iTmp0 = 0
      BEGIN
        EXEC sp_OAGetProperty @ftp, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @chilkatGlob
        EXEC @hr = sp_OADestroy @ftp
        EXEC @hr = sp_OADestroy @taskChain
        RETURN
      END

    -- Add this task to the task chain.
    EXEC sp_OAMethod @taskChain, 'Append', @success OUT, @task
    EXEC @hr = sp_OADestroy @task

    -- Start the task chain running in a background thread.
    -- Each task is run one after the other (on the same background thread) until all tasks have completed.
    -- The task chain will stop at the first task that fails.
    EXEC sp_OASetProperty @taskChain, 'StopOnFailedTask', 1
    EXEC sp_OAMethod @taskChain, 'Run', @success OUT
    IF Not @success
      BEGIN
        EXEC sp_OAGetProperty @taskChain, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @chilkatGlob
        EXEC @hr = sp_OADestroy @ftp
        EXEC @hr = sp_OADestroy @taskChain
        RETURN
      END

    -- The application is now free to do anything else
    -- while the FTP commands are being run...

    -- For this example, we'll simply sleep and periodically
    -- check to see if the taskchain if finished. 
    EXEC sp_OAGetProperty @taskChain, 'Finished', @iTmp0 OUT
    WHILE @iTmp0 <> 1
      BEGIN

        -- Sleep 100 ms.
        EXEC sp_OAMethod @taskChain, 'SleepMs', NULL, 100

      END

    -- A finished task chain could be one that was canceled, aborted, or truly finished.  

    -- If the task chain "completed", then it ran to completion.  A "completed" task will
    -- have a StatusInt equal to 7.   If the task finished, but was not completed, then it must've
    -- been aborted or canceled:
    EXEC sp_OAGetProperty @taskChain, 'StatusInt', @iTmp0 OUT
    IF @iTmp0 <> 7
      BEGIN

        PRINT 'Task did not complete.'

        EXEC sp_OAGetProperty @taskChain, 'Status', @sTmp0 OUT
        PRINT 'task chain status: ' + @sTmp0
        EXEC @hr = sp_OADestroy @chilkatGlob
        EXEC @hr = sp_OADestroy @ftp
        EXEC @hr = sp_OADestroy @taskChain
        RETURN
      END

    -- If we got to this point, the ChangeRemoteDir and PutFile were successful.
    -- We can visually verify by examining the LastErrorText that was recorded for each
    -- of these method calls..
    DECLARE @numTasks int
    EXEC sp_OAGetProperty @taskChain, 'NumTasks', @numTasks OUT
    DECLARE @taskIdx int
    SELECT @taskIdx = 0

    WHILE (@taskIdx < @numTasks)
      BEGIN

        EXEC sp_OAMethod @taskChain, 'GetTask', @task OUT, @taskIdx

        -- Examine the status of this task, and the ResultErrorText
        -- (the ResultErrorText is the ftp.LastErrorText captured for FTP method called by the task).
        -- Everything should indicate success.

        EXEC sp_OAGetProperty @task, 'Status', @sTmp0 OUT
        PRINT 'task status: ' + @sTmp0

        EXEC sp_OAGetProperty @task, 'ResultErrorText', @sTmp0 OUT
        PRINT 'task log: ' + @sTmp0

        EXEC @hr = sp_OADestroy @task

        SELECT @taskIdx = @taskIdx + 1
      END

    EXEC sp_OAMethod @ftp, 'Disconnect', @success OUT

    EXEC @hr = sp_OADestroy @chilkatGlob
    EXEC @hr = sp_OADestroy @ftp
    EXEC @hr = sp_OADestroy @taskChain


END
GO