Change session interceptor to a transform

The difference is that, while both get to intercept and handle the
response, only the transform can change the result that updates the
resource instance.

In this way, it's not necessary to copy the response data onto the
scope anymore because the object is updated properly in place rather
than being updated with the wrapped response containing the csrf
token and flash messages and other parasession data.

h/static/scripts/controllers.coffee

@@ -48,7 +48,7 @@ class App
         frame: $scope.frame or @scope.frame
         socialView: annotator.socialView
         ongoingHighlightSwitch: false
-        model: {}
+        model: session
         search:
           facets: SEARCH_FACETS
           values: SEARCH_VALUES
@@ -62,7 +62,6 @@ class App
       angular.extend annotator.options.Store, options
 
       session.$promise.then (data) ->
-        angular.extend $scope.model, data
         unless data.personas?.length
           $scope.initUpdater()
           $scope.reloadAnnotations()

h/static/scripts/session.coffee

@@ -64,9 +64,14 @@ class SessionProvider
     ($q,   $resource,   baseURI,   flash) ->
       actions = {}
 
-      _process = (response) ->
-        data = response.data
+      process = (data, headersGetter) ->
+        # Parse as json
+        data = angular.fromJson data
+
+        # Lift response data
         model = data.model
+        model.errors = data.errors
+        model.reason = data.reason
 
         # bw compat
         if angular.isObject(data.persona)
@@ -85,19 +90,12 @@ class SessionProvider
         csrfToken = model.csrf
         delete model.csrf
 
-        # Lift the model object so it becomes the response data.
-
-        # Return the response or a rejected response.
-        if data.status is 'failure'
-          $q.reject(data)
-        else
-          model
+        # Return the model
+        model
 
       for name, options of ACTION_OPTION
         actions[name] = angular.extend {}, options, @options
-        actions[name].interceptor =
-          response: _process
-          responseError: _process
+        actions[name].transformResponse = process
 
       $resource("#{baseURI}app", {}, actions).load()
   ]