load the collection instance variable on index action - closes #137

lib/cancan/ability.rb

@@ -221,6 +221,10 @@ module CanCan
       attributes
     end
 
+    def has_block?(action, subject)
+      relevant_can_definitions(action, subject).any?(&:only_block?)
+    end
+
     private
 
     def unauthorized_message_keys(action, subject)

lib/cancan/controller_resource.rb

@@ -28,6 +28,8 @@ module CanCan
     def load_resource
       if !resource_instance && (parent? || member_action?)
         @controller.instance_variable_set("@#{instance_name}", load_resource_instance)
+      elsif load_collection?
+        @controller.instance_variable_set("@#{instance_name.pluralize}", load_collection)
       end
     end
 
@@ -49,6 +51,16 @@ module CanCan
       end
     end
 
+    def load_collection?
+      !parent? && collection_actions.include?(@params[:action].to_sym) &&
+      resource_base.respond_to?(:accessible_by) &&
+      !@controller.current_ability.has_block?(authorization_action, resource_class)
+    end
+
+    def load_collection
+      resource_base.accessible_by(@controller.current_ability)
+    end
+
     def build_resource
       resource = resource_base.send(@options[:singleton] ? "build_#{name}" : "new")
       initial_attributes.each do |name, value|

spec/cancan/ability_spec.rb

@@ -282,6 +282,15 @@ describe CanCan::Ability do
     lambda { @ability.authorize!(:read, :foo) }.should_not raise_error
   end
 
+  it "should know when block is used in conditions" do
+    @ability.can :read, :foo
+    @ability.should_not have_block(:read, :foo)
+    @ability.can :read, :foo do |foo|
+      false
+    end
+    @ability.should have_block(:read, :foo)
+  end
+
   it "should raise access denied exception with default message if not specified" do
     begin
       @ability.authorize! :read, :foo

spec/cancan/controller_resource_spec.rb

@@ -4,8 +4,9 @@ describe CanCan::ControllerResource do
   before(:each) do
     @params = HashWithIndifferentAccess.new(:controller => "projects")
     @controller = Object.new # simple stub for now
+    @ability = Ability.new(nil)
     stub(@controller).params { @params }
-    stub(@controller).current_ability.stub!.attributes_for { {} }
+    stub(@controller).current_ability { @ability }
   end
 
   it "should load the resource into an instance variable if params[:id] is specified" do
@@ -49,7 +50,7 @@ describe CanCan::ControllerResource do
 
   it "should build a new resource with attributes from current ability" do
     @params.merge!(:action => "new")
-    stub(@controller).current_ability.stub!.attributes_for(:new, Project) { {:name => "from conditions"} }
+    @ability.can(:create, Project, :name => "from conditions")
     resource = CanCan::ControllerResource.new(@controller)
     resource.load_resource
     @controller.instance_variable_get(:@project).name.should == "from conditions"
@@ -57,17 +58,37 @@ describe CanCan::ControllerResource do
 
   it "should override initial attributes with params" do
     @params.merge!(:action => "new", :project => {:name => "from params"})
-    stub(@controller).current_ability.stub!.attributes_for(:new, Project) { {:name => "foobar"} }
+    @ability.can(:create, Project, :name => "from conditions")
     resource = CanCan::ControllerResource.new(@controller)
     resource.load_resource
     @controller.instance_variable_get(:@project).name.should == "from params"
   end
 
-  it "should not build a resource when on index action" do
+  it "should build a collection when on index action when class responds to accessible_by" do
+    stub(Project).accessible_by(@ability) { :found_projects }
     @params[:action] = "index"
     resource = CanCan::ControllerResource.new(@controller)
     resource.load_resource
     @controller.instance_variable_get(:@project).should be_nil
+    @controller.instance_variable_get(:@projects).should == :found_projects
+  end
+
+  it "should not build a collection when on index action when class does not respond to accessible_by" do
+    @params[:action] = "index"
+    resource = CanCan::ControllerResource.new(@controller)
+    resource.load_resource
+    @controller.instance_variable_get(:@project).should be_nil
+    @controller.instance_variable_defined?(:@projects).should be_false
+  end
+
+  it "should not use accessible_by when defining abilities through a block" do
+    stub(Project).accessible_by(@ability) { :found_projects }
+    @params[:action] = "index"
+    @ability.can(:read, Project) { |p| false }
+    resource = CanCan::ControllerResource.new(@controller)
+    resource.load_resource
+    @controller.instance_variable_get(:@project).should be_nil
+    @controller.instance_variable_defined?(:@projects).should be_false
   end
 
   it "should perform authorization using controller action and loaded model" do