I don’t think so, although I’m surprised you get the “:” response from a play command. I found the piston didn’t even start.
The problem with media.play is that it sends a multipart message which webcore can not handle. I’ve written a node.js script running on the rasp pi. You point the web hook at it, and change the pi script to call your piston. It seems to work, although I#m still tweaking it. There are more details in this thread. Could you also consider voting for the enhancement request, so the node.js code is not required.
