Express REST server losing payload from Ember-data PUT
I haven't dug in too far, but I think this might be a subtle difference between ember-data and restgen: restgen expects form data (title=foo&body=bar) unless the url ends in ".json". But ember data is uploading json without adding that to the URL.
I haven't yet found any docs from either side indicating how to change the default behavior, but if that is indeed the issue then you should be able to figure out a workaround.
Update: a quick way to check this is to right-click the ajax request in Chrome's Developer Tools, and choose "Copy as cURL", then paste that into a notepad and edit the url to include ".ajax" on the end, then run the command from the command line. If your server processes this correctly, then that's a good sign that we're on the right track.