I looked at the http://shiny.rstudio.com, it looks to me that the shiny server is heavily bounded with shiny UI things. That is, the requests to shiny server could only be invoked via shiny ui widgets.
I would ask whether shiny server supports REST, so that I can use some rest client instead of shiny ui widget to directly call the api that shiny server provides, this would be very helpful for integration between different languages, like java calls R.