(SQL Server) Async Accept Socket Connection

Demonstrates how to get the connected client socket after accepting a connection 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
    -- Important: Do not use nvarchar(max).  See the warning about using nvarchar(max).
    DECLARE @sTmp0 nvarchar(4000)
    -- This example assumes the Chilkat Socket API to have been previously unlocked.
    -- See Socket Unlock Sample for sample code.

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

    -- Bind to a port and listen.
    -- This example will listen at port 5555 and allows for a backlog
    -- of 25 pending connection requests.
    DECLARE @success int
    EXEC sp_OAMethod @listenSocket, 'BindAndListen', @success OUT, 5555, 25
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @listenSocket, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @listenSocket
        RETURN
      END

    -- Start a background task to accept an incoming connection ...
    DECLARE @maxWaitMs int
    SELECT @maxWaitMs = 20000
    DECLARE @acceptTask int
    EXEC sp_OAMethod @listenSocket, 'AcceptNextConnectionAsync', @acceptTask OUT, @maxWaitMs
    EXEC sp_OAMethod @acceptTask, 'Run', @success OUT

    -- ...
    -- ...
    -- ...

    -- Imagine at this point the task has completed successfully,
    -- and a connection was accepted.  Here's how to get the connected socket...
    DECLARE @connectedClient int
    -- Use "Chilkat_9_5_0.Socket" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.Socket', @connectedClient OUT

    EXEC sp_OAMethod @connectedClient, 'LoadTaskResult', @success OUT, @acceptTask

    -- Here's how it works:  The AcceptNextConnection method would normally
    -- return a socket object when called synchronously.  When called asynchronously,
    -- it cannot do so because it returns the task object.  When the async method
    -- (running in a background thread) completes, the socket object that is the client
    -- connection is contained within the task object.
    -- 
    -- This can be generalized for any case where a Chilkat method returns an object.
    -- The async version of that method is such that the object returned in the background
    -- thread is contained within the task object.

    -- To get the result object, we create a new object instance of that type.
    -- In this case, we create a socket object (connectedClient).  There is a LoadTaskResult
    -- method in all Chilkat classes that can be a return value of an async method call.
    -- The LoadTaskResult method transfers the returned object from the task to the caller.

    EXEC @hr = sp_OADestroy @listenSocket
    EXEC @hr = sp_OADestroy @connectedClient


END
GO