(SQL Server) Asynchronous Sockets - Reading/Writing Data

Demonstrates the following using async methods:

Demonstrates receiving text on a socket connection up to and including when an expected CRLF arrives. The example sends an HTTP HEAD request to an HTTP server and then reads the response header using ReceiveToCRLF and ReceiveUntilMatch.

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

    -- Connect using TLS to www.chilkatsoft.com
    -- We could also use a normal TCP connection also by specifying port 80 with useTls = 0.
    DECLARE @useTls int
    SELECT @useTls = 1
    DECLARE @maxWaitMillisec int
    SELECT @maxWaitMillisec = 20000
    DECLARE @connectTask int
    EXEC sp_OAMethod @socket, 'ConnectAsync', @connectTask OUT, 'www.chilkatsoft.com', 443, @useTls, @maxWaitMillisec
    EXEC sp_OAGetProperty @socket, 'LastMethodSuccess', @iTmp0 OUT
    IF @iTmp0 <> 1
      BEGIN
        EXEC sp_OAGetProperty @socket, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @socket
        RETURN
      END

    -- Schedule the task for running on the thread pool.  This changes the task's state
    -- from Inert to Live.
    DECLARE @success int
    EXEC sp_OAMethod @connectTask, 'Run', @success OUT
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @connectTask, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @connectTask

        EXEC @hr = sp_OADestroy @socket
        RETURN
      END

    -- The application is now free to do anything else.
    -- For programming languages where Chilkat supports events, a TaskCompleted
    -- event will fire when the task is completed.

    -- For this example, we'll simply sleep and periodically
    -- check to see when the connection is ready.
    EXEC sp_OAGetProperty @connectTask, 'Finished', @iTmp0 OUT
    WHILE @iTmp0 <> 1
      BEGIN

        -- Sleep 10 ms.
        EXEC sp_OAMethod @connectTask, 'SleepMs', NULL, 10

      END

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

    -- If the task was "canceled", it was canceled prior to actually starting.  This could
    -- happen if the task was canceled while waiting in a thread pool queue to be scheduled by Chilkat's
    -- background thread pool scheduler.  

    -- If the task was "aborted", it indicates that it was canceled while running in a background thread.  
    -- The ResultErrorText will likely indicate that the task was aborted.

    -- If the task "completed", then it ran to completion, but the actual success/failure of the method
    -- is determined by the result obtained via a GetResult* method.  (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 @connectTask, 'StatusInt', @iTmp0 OUT
    IF @iTmp0 <> 7
      BEGIN

        PRINT 'Task did not complete.'

        EXEC sp_OAGetProperty @connectTask, 'Status', @sTmp0 OUT
        PRINT 'task status: ' + @sTmp0
        EXEC @hr = sp_OADestroy @connectTask

        EXEC @hr = sp_OADestroy @socket
        RETURN
      END
    DECLARE @connectSuccess int
    EXEC sp_OAMethod @connectTask, 'GetResultBool', @connectSuccess OUT
    IF @connectSuccess <> 1
      BEGIN

        PRINT 'Connect failed.'
        EXEC sp_OAGetProperty @connectTask, 'ResultErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @connectTask

        EXEC @hr = sp_OADestroy @socket
        RETURN
      END
    EXEC @hr = sp_OADestroy @connectTask

    -- Tell the socket object that all text is to be sent in the utf-8 encoding,
    -- and the text received is assumed to be utf-8.
    EXEC sp_OASetProperty @socket, 'StringCharset', 'utf-8'

    -- Send an HTTP HEAD request:
    DECLARE @sendTask int
    EXEC sp_OAMethod @socket, 'SendStringAsync', @sendTask OUT, 'HEAD / HTTP/1.1' + CHAR(13) + CHAR(10) + 'Host: www.chilkatsoft.com' + CHAR(13) + CHAR(10) + CHAR(13) + CHAR(10)
    EXEC sp_OAGetProperty @socket, 'LastMethodSuccess', @iTmp0 OUT
    IF @iTmp0 <> 1
      BEGIN
        EXEC sp_OAGetProperty @socket, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @socket
        RETURN
      END
    EXEC sp_OAMethod @sendTask, 'Run', @success OUT
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @sendTask, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @sendTask

        EXEC @hr = sp_OADestroy @socket
        RETURN
      END
    -- The application is now free to do anything else.
    -- For programming languages where Chilkat supports events, 
    -- a TaskCompleted event will fire when the task is completed.
    -- This example will simply wait until the task completes...
    EXEC sp_OAGetProperty @sendTask, 'Finished', @iTmp0 OUT
    WHILE @iTmp0 <> 1
      BEGIN
        -- Sleep 10 ms.
        EXEC sp_OAMethod @sendTask, 'SleepMs', NULL, 10
      END
    EXEC sp_OAGetProperty @sendTask, 'StatusInt', @iTmp0 OUT
    IF @iTmp0 <> 7
      BEGIN

        PRINT 'Task did not complete.'

        EXEC sp_OAGetProperty @sendTask, 'Status', @sTmp0 OUT
        PRINT 'task status: ' + @sTmp0
        EXEC @hr = sp_OADestroy @sendTask

        EXEC @hr = sp_OADestroy @socket
        RETURN
      END
    DECLARE @sendSuccess int
    EXEC sp_OAMethod @sendTask, 'GetResultBool', @sendSuccess OUT
    IF @sendSuccess <> 1
      BEGIN

        PRINT 'Send failed.'
        EXEC sp_OAGetProperty @sendTask, 'ResultErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @sendTask

        EXEC @hr = sp_OADestroy @socket
        RETURN
      END
    EXEC @hr = sp_OADestroy @sendTask

    -- Wait a maximum of 4 seconds while no data is forthcoming:
    EXEC sp_OASetProperty @socket, 'MaxReadIdleMs', 4000

    -- To explain MaxReadIdleMs further:  In Chilkat, a max "idle timeout" is the max time to wait
    -- while no additional data arrives on the socket.  Imagine if 10MB of data will be received
    -- where the 1st CRLF occurs at the very end.  As long as the data continues arriving and does not
    -- halt for more than 4000ms, then the ReceiveToCRLF will continue receiving.  It is only after
    -- the connection becomes idle for more than 4000ms that the app will giveup and fail the read.

    -- Get the 1st response line, which should be "HTTP/1.1 200 OK"
    DECLARE @receiveTask int
    EXEC sp_OAMethod @socket, 'ReceiveToCRLFAsync', @receiveTask OUT
    EXEC sp_OAGetProperty @socket, 'LastMethodSuccess', @iTmp0 OUT
    IF @iTmp0 <> 1
      BEGIN
        EXEC sp_OAGetProperty @socket, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @socket
        RETURN
      END
    EXEC sp_OAMethod @receiveTask, 'Run', @success OUT
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @receiveTask, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @receiveTask

        EXEC @hr = sp_OADestroy @socket
        RETURN
      END
    -- The application is now free to do anything else.
    -- For programming languages where Chilkat supports events, 
    -- a TaskCompleted event will fire when the task is completed.
    -- This example will simply wait until the task completes...
    EXEC sp_OAGetProperty @receiveTask, 'Finished', @iTmp0 OUT
    WHILE @iTmp0 <> 1
      BEGIN
        -- Sleep 10 ms.
        EXEC sp_OAMethod @receiveTask, 'SleepMs', NULL, 10
      END
    EXEC sp_OAGetProperty @receiveTask, 'StatusInt', @iTmp0 OUT
    IF @iTmp0 <> 7
      BEGIN

        PRINT 'Task did not complete.'

        EXEC sp_OAGetProperty @receiveTask, 'Status', @sTmp0 OUT
        PRINT 'task status: ' + @sTmp0
        EXEC @hr = sp_OADestroy @receiveTask

        EXEC @hr = sp_OADestroy @socket
        RETURN
      END
    DECLARE @responseStatusLine nvarchar(4000)
    EXEC sp_OAMethod @receiveTask, 'GetResultString', @responseStatusLine OUT


    PRINT 'StatusLine: ' + @responseStatusLine
    EXEC @hr = sp_OADestroy @receiveTask

    -- Now get the 1st line of the response header:
    DECLARE @responseHeaderLine nvarchar(4000)
    EXEC sp_OAMethod @socket, 'ReceiveToCRLF', @responseHeaderLine OUT
    EXEC sp_OAGetProperty @socket, 'LastMethodSuccess', @iTmp0 OUT
    IF @iTmp0 <> 1
      BEGIN
        EXEC sp_OAGetProperty @socket, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @socket
        RETURN
      END


    PRINT 'HeaderLine: ' + @responseHeaderLine

    -- Now read the remainder of the response header by reading until a double CRLF is seen:
    EXEC sp_OAMethod @socket, 'ReceiveUntilMatchAsync', @receiveTask OUT, CHAR(13) + CHAR(10) + CHAR(13) + CHAR(10)
    EXEC sp_OAGetProperty @socket, 'LastMethodSuccess', @iTmp0 OUT
    IF @iTmp0 <> 1
      BEGIN
        EXEC sp_OAGetProperty @socket, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @socket
        RETURN
      END
    EXEC sp_OAMethod @receiveTask, 'Run', @success OUT
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @receiveTask, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @receiveTask

        EXEC @hr = sp_OADestroy @socket
        RETURN
      END
    -- The application is now free to do anything else.
    -- For programming languages where Chilkat supports events, 
    -- a TaskCompleted event will fire when the task is completed.
    -- This example will simply wait until the task completes...
    EXEC sp_OAGetProperty @receiveTask, 'Finished', @iTmp0 OUT
    WHILE @iTmp0 <> 1
      BEGIN
        -- Sleep 10 ms.
        EXEC sp_OAMethod @receiveTask, 'SleepMs', NULL, 10
      END
    EXEC sp_OAGetProperty @receiveTask, 'StatusInt', @iTmp0 OUT
    IF @iTmp0 <> 7
      BEGIN

        PRINT 'Task did not complete.'

        EXEC sp_OAGetProperty @receiveTask, 'Status', @sTmp0 OUT
        PRINT 'task status: ' + @sTmp0
        EXEC @hr = sp_OADestroy @receiveTask

        EXEC @hr = sp_OADestroy @socket
        RETURN
      END
    DECLARE @remainderOfHeader nvarchar(4000)
    EXEC sp_OAMethod @receiveTask, 'GetResultString', @remainderOfHeader OUT


    PRINT 'Remainder: ' + @remainderOfHeader
    EXEC @hr = sp_OADestroy @receiveTask

    -- Close the connection with the server
    -- Wait a max of 20 seconds (20000 millsec)
    EXEC sp_OAMethod @socket, 'Close', @success OUT, 20000

    EXEC @hr = sp_OADestroy @socket


END
GO