Grape::Entity#serializable_hash should call #serializable_hash if the data returned from #value_for responds to that method so that nested Grape::Entity presentation works correctly.

Author: goodwink

lib/grape/entity.rb

@@ -232,7 +232,10 @@ def serializable_hash(runtime_options = {})
       return nil if object.nil?
       opts = options.merge(runtime_options || {})
       exposures.inject({}) do |output, (attribute, exposure_options)|
-        output[key_for(attribute)] = value_for(attribute, opts) if conditions_met?(exposure_options, opts)
+        partial_output = value_for(attribute, opts) if conditions_met?(exposure_options, opts)
+        partial_output = partial_output.serializable_hash(runtime_options) if partial_output.respond_to? :serializable_hash
+        output[key_for(attribute)] = partial_output
+        
         output
       end
     end

spec/grape/entity_spec.rb

@@ -257,6 +257,28 @@
         fresh_class.expose :name
         expect{ fresh_class.new(nil).serializable_hash }.not_to raise_error
       end
+
+      it 'should serialize embedded objects which respond to #serializable_hash' do
+        class EmbeddedExample
+          def serializable_hash(opts = {})
+            {:abc => 'def'}
+          end
+        end
+
+        class SimpleExample
+          def name
+            "abc"
+          end
+
+          def embedded
+            EmbeddedExample.new
+          end
+        end
+
+        fresh_class.expose :name, :embedded
+        presenter = fresh_class.new(SimpleExample.new)
+        presenter.serializable_hash.should == {:name => "abc", :embedded => {:abc => "def"}}
+      end
     end
 
     describe '#value_for' do