SQL Server

Receive Text until CRLF

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. SQL Server

-- 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)
    DECLARE @success int
    SELECT @success = 0

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

    DECLARE @socket int
    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
    EXEC sp_OAMethod @socket, 'Connect', @success OUT, 'www.chilkatsoft.com', 443, @useTls, @maxWaitMillisec
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @socket, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @socket
        RETURN
      END

    -- 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:
    EXEC sp_OAMethod @socket, 'SendString', @success OUT, 'HEAD / HTTP/1.1' + CHAR(13) + CHAR(10) + 'Host: www.chilkatsoft.com' + CHAR(13) + CHAR(10) + CHAR(13) + CHAR(10)
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @socket, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @socket
        RETURN
      END

    -- 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 @responseStatusLine nvarchar(4000)
    EXEC sp_OAMethod @socket, 'ReceiveToCRLF', @responseStatusLine 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 'StatusLine: ' + @responseStatusLine

    -- 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:
    DECLARE @remainderOfHeader nvarchar(4000)
    EXEC sp_OAMethod @socket, 'ReceiveUntilMatch', @remainderOfHeader 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


    PRINT 'Remainder: ' + @remainderOfHeader

    -- 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