adding :instance_name option to load/authorize_resource - closes #44

lib/cancan/controller_resource.rb

@@ -25,7 +25,7 @@ module CanCan
 
     def load_resource
       if !resource_instance && (parent? || member_action?)
-        @controller.instance_variable_set("@#{name}", load_resource_instance)
+        @controller.instance_variable_set("@#{instance_name}", load_resource_instance)
       end
     end
 
@@ -72,7 +72,7 @@ module CanCan
     end
 
     def resource_instance
-      @controller.instance_variable_get("@#{name}")
+      @controller.instance_variable_get("@#{instance_name}")
     end
 
     # The object that methods (such as "find", "new" or "build") are called on.
@@ -94,6 +94,10 @@ module CanCan
       @params[:controller].sub("Controller", "").underscore.split('/').last.singularize
     end
 
+    def instance_name
+      @options[:instance_name] || name
+    end
+
     def collection_actions
       [:index] + [@options[:collection]].flatten
     end

spec/cancan/controller_resource_spec.rb

@@ -179,6 +179,15 @@ describe CanCan::ControllerResource do
     lambda { resource.authorize_resource }.should raise_error(CanCan::AccessDenied)
   end
 
+  it "should load and authorize using custom instance name" do
+    @params.merge!(:action => "show", :id => 123)
+    stub(Ability).find(123) { :some_ability }
+    stub(@controller).authorize!(:show, :some_ability) { raise CanCan::AccessDenied }
+    resource = CanCan::ControllerResource.new(@controller, :instance_name => :custom_ability)
+    lambda { resource.load_and_authorize_resource }.should raise_error(CanCan::AccessDenied)
+    @controller.instance_variable_get(:@custom_ability).should == :some_ability
+  end
+
   it "should raise ImplementationRemoved when adding :name option" do
     lambda {
       CanCan::ControllerResource.new(@controller, :name => :foo)