Fixed, that models with custom as_indexed_json method are properly serialized during update

Previously, the `update_document` method simply intercepted the changes to the model, via the
`@__changed_attributes` variable, and used these directly.

This caused models with a custom serialization method to be incorrectly serialized, namely
unwanted attributes were added.

This patch looks for `as_indexed_json` defined on the model, and when it finds it,
filters the changed attributes through the keys.

Closes elastic#75

Related:

* elastic#59
* elastic#57
* elastic#52
* elastic#40
* elastic#37
* elastic#5

Author: karmi

elasticsearch-model/lib/elasticsearch/model/indexing.rb

@@ -333,11 +333,17 @@ def delete_document(options={})
         #
         def update_document(options={})
           if changed_attributes = self.instance_variable_get(:@__changed_attributes)
+            attributes = if respond_to?(:as_indexed_json)
+              changed_attributes.select { |k,v| self.as_indexed_json.keys.include? k }
+            else
+              changed_attributes
+            end
+
             client.update(
               { index: index_name,
                 type:  document_type,
                 id:    self.id,
-                body:  { doc: changed_attributes } }.merge(options)
+                body:  { doc: attributes } }.merge(options)
             )
           else
             index_document(options)

elasticsearch-model/test/integration/active_record_custom_serialization_test.rb

@@ -0,0 +1,61 @@
+require 'test_helper'
+
+module Elasticsearch
+  module Model
+    class ActiveRecordCustomSerializationTest < Elasticsearch::Test::IntegrationTestCase
+
+      class ::ArticleWithCustomSerialization < ActiveRecord::Base
+        include Elasticsearch::Model
+        include Elasticsearch::Model::Callbacks
+
+        mapping do
+          indexes :title
+        end
+
+        def as_indexed_json(options={})
+          as_json(options.merge root: false).slice('title')
+        end
+      end
+
+      context "ActiveRecord model with custom JSON serialization" do
+        setup do
+          ActiveRecord::Schema.define(:version => 1) do
+            create_table ArticleWithCustomSerialization.table_name do |t|
+              t.string   :title
+              t.string   :status
+            end
+          end
+
+          ArticleWithCustomSerialization.delete_all
+          ArticleWithCustomSerialization.__elasticsearch__.create_index! force: true
+        end
+
+        should "index only the title attribute when creating" do
+          ArticleWithCustomSerialization.create! title: 'Test', status: 'green'
+
+          a = ArticleWithCustomSerialization.__elasticsearch__.client.get \
+                index: 'article_with_custom_serializations',
+                type:  'article_with_custom_serialization',
+                id:    '1'
+
+          assert_equal( { 'title' => 'Test' }, a['_source'] )
+        end
+
+        should "index only the title attribute when updating" do
+          ArticleWithCustomSerialization.create! title: 'Test', status: 'green'
+
+          article = ArticleWithCustomSerialization.first
+          article.update_attributes title: 'UPDATED', status: 'red'
+
+          a = ArticleWithCustomSerialization.__elasticsearch__.client.get \
+                index: 'article_with_custom_serializations',
+                type:  'article_with_custom_serialization',
+                id:    '1'
+
+          assert_equal( { 'title' => 'UPDATED' }, a['_source'] )
+        end
+      end
+
+    end
+  end
+end

elasticsearch-model/test/unit/indexing_test.rb

@@ -129,6 +129,25 @@ def changes
         end
       end
 
+      class ::DummyIndexingModelWithCallbacksAndCustomAsIndexedJson
+        extend  Elasticsearch::Model::Indexing::ClassMethods
+        include Elasticsearch::Model::Indexing::InstanceMethods
+
+        def self.before_save(&block)
+          (@callbacks ||= {})[block.hash] = block
+        end
+
+        def changed_attributes; [:foo, :bar]; end
+
+        def changes
+          {:foo => ['A', 'B'], :bar => ['C', 'D']}
+        end
+
+        def as_indexed_json(options={})
+          { :foo => 'B' }
+        end
+      end
+
       should "register before_save callback when included" do
         ::DummyIndexingModelWithCallbacks.expects(:before_save).returns(true)
         ::DummyIndexingModelWithCallbacks.__send__ :include, Elasticsearch::Model::Indexing::InstanceMethods
@@ -251,6 +270,25 @@ def changes
 
         instance.update_document
       end
+
+      should "exclude attributes not contained in custom as_indexed_json during partial update" do
+        client   = mock('client')
+        instance = ::DummyIndexingModelWithCallbacksAndCustomAsIndexedJson.new
+
+        # Set the fake `changes` hash
+        instance.instance_variable_set(:@__changed_attributes, {foo: 'B', bar: 'D' })
+
+        client.expects(:update).with do |payload|
+          assert_equal({foo: 'B'}, payload[:body][:doc])
+        end
+
+        instance.expects(:client).returns(client)
+        instance.expects(:index_name).returns('foo')
+        instance.expects(:document_type).returns('bar')
+        instance.expects(:id).returns('1')
+
+        instance.update_document
+      end
     end
 
     context "Re-creating the index" do