It shouldn't be too hard to do in Lua right?
--[[ Request header is something like this:
GET / HTTP/1.0
Host: cuberite.org
Other-Stuff: Info for other stuff
More-Stuff: Even more stuff
]]
local Headers = StringSplit(RawRequest:match("^.-\r\n\r\n"), "\n")
local PostInformation = StringSplit(Headers[#Headers], "&"):sub(2) -- Post starts with a question mark.