adding :through_association option to load_resource (thanks hunterae) - closes #171

lib/cancan/controller_additions.rb

@@ -71,6 +71,10 @@ module CanCan
       # [:+through+]
       #   Load this resource through another one. This should match the name of the parent instance variable or method.
       #
+      # [:+through_association+]
+      #   The name of the association to fetch the child records through the parent resource. This is normally not needed
+      #   because it defaults to the pluralized resource name.
+      #
       # [:+shallow+]
       #   Pass +true+ to allow this resource to be loaded directly when parent is +nil+. Defaults to +false+.
       #

lib/cancan/controller_resource.rb

@@ -136,7 +136,7 @@ module CanCan
     def resource_base
       if @options[:through]
         if parent_resource
-          @options[:singleton] ? parent_resource : parent_resource.send(name.to_s.pluralize)
+          @options[:singleton] ? parent_resource : parent_resource.send(@options[:through_association] || name.to_s.pluralize)
         elsif @options[:shallow]
           resource_class
         else

spec/cancan/controller_resource_spec.rb

@@ -174,6 +174,16 @@ describe CanCan::ControllerResource do
     @controller.instance_variable_get(:@project).should == :some_project
   end
 
+  it "should load resource through the custom association name" do
+    @params.merge!(:action => "show", :id => 123)
+    category = Object.new
+    @controller.instance_variable_set(:@category, category)
+    stub(category).custom_projects.stub!.find(123) { :some_project }
+    resource = CanCan::ControllerResource.new(@controller, :through => :category, :through_association => :custom_projects)
+    resource.load_resource
+    @controller.instance_variable_get(:@project).should == :some_project
+  end
+
   it "should load resource through the association of another parent resource using method" do
     @params.merge!(:action => "show", :id => 123)
     category = Object.new