Send a 4-byte Length Prefix over a Socket

See more Socket/SSL/TLS Examples

Demonstrates Socket.SendCount, which sends a four-byte length prefix in network byte order. This is typically used to tell the peer how many bytes follow.

--
CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    DECLARE @sTmp0 nvarchar(4000)
    DECLARE @success int
    SELECT @success = 0

    DECLARE @socket int
    EXEC @hr = sp_OACreate 'Chilkat.Socket', @socket OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    --  Connect to the server using TLS.
    DECLARE @bTls int
    SELECT @bTls = 1
    DECLARE @maxWaitMs int
    SELECT @maxWaitMs = 5000
    EXEC sp_OAMethod @socket, 'Connect', @success OUT, 'example.com', 5000, @bTls, @maxWaitMs
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @socket, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @socket
        RETURN
      END

    --  Send a four-byte length prefix in network byte order.  A common framing pattern is to send the
    --  number of bytes in a message before the message itself, so the peer knows exactly how many bytes
    --  to read.
    DECLARE @messageLength int
    SELECT @messageLength = 512
    EXEC sp_OAMethod @socket, 'SendCount', @success OUT, @messageLength
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @socket, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @socket
        RETURN
      END

    PRINT 'Length prefix sent.'

    EXEC @hr = sp_OADestroy @socket


END
GO