Merge pull request ruby-grape#151 from bobbytables/frontier-exposure-inheritance

Exposure Inheritance

Author: Michael Bleigh

lib/grape/entity.rb

@@ -78,11 +78,17 @@ def self.expose(*args, &block)
       end
     end
 
-    # Returns a hash of exposures that have been declared for this Entity. The keys
+    # Returns a hash of exposures that have been declared for this Entity or ancestors. The keys
     # are symbolized references to methods on the containing object, the values are
     # the options that were passed into expose.
     def self.exposures
-      (@exposures ||= {})
+      @exposures ||= {}
+
+      if superclass.respond_to? :exposures
+        @exposures = superclass.exposures.merge(@exposures)
+      end
+
+      @exposures
     end
 
     # This allows you to set a root element name for your representation.

spec/grape/entity_spec.rb

@@ -39,6 +39,34 @@
           subject.exposures[:name][:proc].should == block
         end
       end
+
+      context 'inherited exposures' do
+        it 'should return exposures from an ancestor' do
+          subject.expose :name, :email
+          child_class = Class.new(subject)
+
+          child_class.exposures.should eq(subject.exposures)
+        end
+
+        it 'should return exposures from multiple ancestor' do
+          subject.expose :name, :email
+          parent_class = Class.new(subject)
+          child_class  = Class.new(parent_class)
+
+          child_class.exposures.should eq(subject.exposures)
+        end
+
+        it 'should return descendant exposures as a priotity' do
+          subject.expose :name, :email
+          child_class = Class.new(subject)
+          child_class.expose :name do |n|
+            'foo'
+          end
+
+          subject.exposures[:name].should_not have_key :proc
+          child_class.exposures[:name].should have_key :proc
+        end
+      end
     end
 
     describe '.represent' do