diff --git a/lib/dunlop/ember/api_base_controller.rb b/lib/dunlop/ember/api_base_controller.rb
index e5fe939..8d8b2ec 100644
--- a/lib/dunlop/ember/api_base_controller.rb
+++ b/lib/dunlop/ember/api_base_controller.rb
@@ -2,6 +2,7 @@ module Dunlop::Ember::ApiBaseController
   extend ActiveSupport::Concern
 
   included do
+    cattr_accessor :predicate_end_matcher
     before_action :authenticate_user_from_token!
     before_action :authenticate_user!
     before_action :set_current_user
@@ -174,6 +175,7 @@ module Dunlop::Ember::ApiBaseController
     {}
   end
 
+  # predicate_end_matcher =>
   # /(_eq|_eq_any|_eq_all|_not_eq|_not_eq_any|_not_eq_all|_matches|_matches_any|_matches_all|
   #   _does_not_match|_does_not_match_any|_does_not_match_all|_lt|_lt_any|_lt_all|_lteq|_lteq_any|
   #   _lteq_all|_gt|_gt_any|_gt_all|_gteq|_gteq_any|_gteq_all|_in|_in_any|_in_all|_not_in|_not_in_any|
@@ -181,13 +183,13 @@ module Dunlop::Ember::ApiBaseController
   #   _not_cont_all|_i_not_cont|_i_not_cont_any|_i_not_cont_all|_start|_start_any|_start_all|_not_start|
   #   _not_start_any|_not_start_all|_end|_end_any|_end_all|_not_end|_not_end_any|_not_end_all|
   #   _true|_not_true|_false|_not_false|_present|_blank|_null|_not_null)$/
-  PREDICATE_END_MATCHER = Regexp.new("(_#{Ransack.predicates.keys.join('|_')})$")
 
   #TODO: make me pretty, specs are in place
   def query
+    self.class.predicate_end_matcher ||= Regexp.new("(_#{Ransack.predicates.keys.join('|_')})$")
     mapped_query = {}
     (params[:q] || {}).each do |key, value|
-      key = "#{key}_eq" unless %w[s sorts].include?(key) or record_class.try(:ransackable_scopes).try(:include?, key.to_sym) or key =~ PREDICATE_END_MATCHER # expect equality when no predicate is given
+      key = "#{key}_eq" unless %w[s sorts].include?(key) or record_class.try(:ransackable_scopes).try(:include?, key.to_sym) or key =~ self.class.predicate_end_matcher # expect equality when no predicate is given
       if key =~ /^type_/
         # map type to sti_type
         mapped_value = case value
@@ -204,6 +206,9 @@ module Dunlop::Ember::ApiBaseController
   end
 
   def _render_with_renderer_json(resource, options = {})
+    if resource == nil
+      return params[:id].blank? ? '{"data":[]}' : '{"data":null}'
+    end
     return resource.to_json if resource.is_a?(Hash)
     return resource if resource.is_a?(String)