I am building an ember.js application and am hung up on authentication. The json rest backend is rails. Every request is authenticated using a session cookie (warden).
AFAIK this is not addressed by the current implementation of ember-data and the ember-data README states that "Handle error states" is on the Roadmap.
For the time being, you can implement your own error handling adapter. Take a look at the implementation of the DS.RestAdapter . By using that as a starter, it should not be too difficult to add error handling in there (e.g simply add an error function to the the data hash that is passed to the jQuery.ajax call).