This is a spirit of transferrance, taking information from your app and delivering it into QuickBooks, then taking the message received from there & delivering back a response.
Because it's simpler than writing something like this on your own.
Build it using VS 2010 or above (or your favorite C# compiler), and open QuickBooks. It will use whatever file is open, and will (as of this writing) only accept TCP requests from localhost on port 3000. Though it's asynchronous, so in theory you should be able to flood QB with enough information to make it cry.
There is no error-checking, nothing to validate your QBXML and nothing to prevent you from breaking everything. There really isn't much security besides only accepting info from localhost but that's flimsy at best.
No, hopefully I will eventually implement an QBXML checker so some invalid requests get bounced back right away, without bothering QB. Also an actual security model would be nice.
Sure! Fork it, make your changes in a new branch, then make a pull request.