From dbb7587d971dcb23c2d6a7b7f82d812fd929485b Mon Sep 17 00:00:00 2001
From: Adam Gotterer <agotterer@gmail.com>
Date: Fri, 13 Jul 2012 16:06:59 -0400
Subject: [PATCH] Improved Entity#serializable_hash to check that an attribute
 exists on an object before accessing it.

Improved Entity#serializable_hash check for an entity on an object before accessing the value.

Converted proc and using condition to #conditions_met
---
 CHANGELOG.markdown        |  4 ++++
 lib/grape/entity.rb       |  5 ++++-
 spec/grape/entity_spec.rb | 25 +++++++++++++++++++++++++
 3 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.markdown b/CHANGELOG.markdown
index 538d174d45..4c1b30902e 100644
--- a/CHANGELOG.markdown
+++ b/CHANGELOG.markdown
@@ -1,3 +1,7 @@
+0.2.2
+=================
+* [#203](https://github.com/intridea/grape/pull/203): Added a check to Entity#serializable_hash that verifies an entity exists on an object - [@adamgotterer](https://github.com/adamgotterer).
+
 0.2.1 (7/11/2012)
 =================
 
diff --git a/lib/grape/entity.rb b/lib/grape/entity.rb
index 890cf83849..3b013f64d2 100644
--- a/lib/grape/entity.rb
+++ b/lib/grape/entity.rb
@@ -259,7 +259,10 @@ 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)
+        if object.respond_to?(attribute) && conditions_met?(exposure_options, opts)
+          output[key_for(attribute)] = value_for(attribute, opts) 
+        end
+
         output
       end
     end
diff --git a/spec/grape/entity_spec.rb b/spec/grape/entity_spec.rb
index 305806724d..eb9b4c637b 100644
--- a/spec/grape/entity_spec.rb
+++ b/spec/grape/entity_spec.rb
@@ -257,6 +257,31 @@
         fresh_class.expose :name
         expect{ fresh_class.new(nil).serializable_hash }.not_to raise_error
       end
+
+      it 'should not throw an exception when an attribute is not found on the object' do
+        fresh_class.expose :name, :non_existant_attribute
+        expect{ fresh_class.new(model).serializable_hash }.not_to raise_error
+      end
+
+      it "should not expose attributes that don't exist on the object" do
+        fresh_class.expose :email, :non_existant_attribute, :name
+
+        res = fresh_class.new(model).serializable_hash
+        res.should have_key :email
+        res.should_not have_key :non_existant_attribute
+        res.should have_key :name
+      end
+
+      it "should not expose attributes that don't exist on the object, even with criteria" do
+        fresh_class.expose :email
+        fresh_class.expose :non_existant_attribute, :if => lambda { false }
+        fresh_class.expose :non_existant_attribute2, :if => lambda { true }
+
+        res = fresh_class.new(model).serializable_hash
+        res.should have_key :email
+        res.should_not have_key :non_existant_attribute
+        res.should_not have_key :non_existant_attribute2
+      end
     end
 
     describe '#value_for' do