Attempt to workaround problem reported about empty plc.xml after unrelated crash. Now, if etree model is corrupted in a way tostring() would generate an empty string, exception prevents saving.
These classes are intended for use server-side.
e.g. in a django view.py :
from pyjs.jsonrpc.django import JSONService, jsonremote
jsonservice = JSONRPCService()
@jsonremote(jsonservice)
def test(request, echo_param):
return "echoing the param back: %s" % echo_param