Merge pull request #52 from aantix/master

Added support for hashes for the extract! method.

lib/jbuilder.rb

@@ -138,10 +138,16 @@ def array!(collection)
     end
   end
 
-  # Extracts the mentioned attributes from the passed object and turns them into attributes of the JSON.
+  # Extracts the mentioned attributes or hash elements from the passed object and turns them into attributes of the JSON.
   #
   # Example:
   #
+  #   @person = Struct.new(:name, :age).new("David", 32)
+  #
+  #   or you can utilize a Hash
+  #
+  #   @person = {:name => "David", :age => 32}
+  #
   #   json.extract! @person, :name, :age
   #
   #   { "name": David", "age": 32 }, { "name": Jamie", "age": 31 }
@@ -150,9 +156,13 @@ def array!(collection)
   #
   #   json.(@person, :name, :age)
   def extract!(object, *attributes)
-    attributes.each do |attribute|
-      __send__ attribute, object.send(attribute)
+    p = if object.is_a?(Hash)
+      lambda{|attribute| __send__ attribute, object.send(:fetch, attribute)}
+    else
+      lambda{|attribute| __send__ attribute, object.send(attribute)}
     end
+
+    attributes.each{|attribute| p.call(attribute)}
   end
 
   if RUBY_VERSION > '1.9'

test/jbuilder_test.rb

@@ -67,7 +67,20 @@ class JbuilderTest < ActiveSupport::TestCase
       assert_equal 32, parsed["age"]
     end
   end
-
+
+  test "extracting from hash" do
+    person = {:name => "Jim", :age => 34}
+
+    json = Jbuilder.encode do |json|
+      json.extract! person, :name, :age
+    end
+
+    JSON.parse(json).tap do |parsed|
+      assert_equal "Jim", parsed["name"]
+      assert_equal 34, parsed["age"]
+    end
+  end
+
   test "nesting single child with block" do
     json = Jbuilder.encode do |json|
       json.author do |json|