Well, I think there might have been a real mySQL-plugin, but I don't know what happened to that. Also, maybe a security-problem?
What I *do* know, however, is that peacekeeper's site has a GSHTTP-plugin. With that, you can send and receive Post and Get-requests. Then, you do the actual processing on the server. That makes it possible for you to check input there to guard against harmful stuff.