I have used a lot time on trial-and-error for the makeWebRequest function. Using a very simple service it works for JSON, but not for XML.
var url = "http://www.broadbandmap.gov/broadbandmap/demographic/jun2014/nation";
// WORKS
Comm.makeWebRequest(url, {"format" => "json"}, {}, method(:onReceive));
// FAILS for XML with responseCode "Failed to load Error: -400"
Comm.makeWebRequest(url, {}, {}, method(:onReceive));
For the XML scenario I have tried all sorts of different options, but always fails. Anyone who can make an working example?