[MODEL] Removed the delegation of indexing/serializing methods from model instance to proxy

Added reversed delegation from the proxy to the instance, when it
defines the `as_indexed_json` method, to pick it up when calling
`index/update_document.

Author: karmi

elasticsearch-model/lib/elasticsearch/model.rb

@@ -90,6 +90,12 @@ def self.included(base)
           include Elasticsearch::Model::Serializing::InstanceMethods
         end
 
+        Elasticsearch::Model::Proxy::InstanceMethodsProxy.class_eval <<-CODE, __FILE__, __LINE__ + 1
+          def as_indexed_json(options={})
+            target.respond_to?(:as_indexed_json) ? target.__send__(:as_indexed_json, options) : super
+          end
+        CODE
+
         # Delegate important methods to the `__elasticsearch__` proxy, unless they are defined already
         #
         extend  Support::Forwardable
@@ -101,11 +107,6 @@ def self.included(base)
         forward :'self.__elasticsearch__', :document_type unless respond_to?(:document_type)
         forward :'self.__elasticsearch__', :import        unless respond_to?(:import)
 
-        instance_delegate [:as_indexed_json] => :__elasticsearch__
-        instance_delegate [:index_document]  => :__elasticsearch__
-        instance_delegate [:update_document] => :__elasticsearch__
-        instance_delegate [:delete_document] => :__elasticsearch__
-
         # Mix the importing module into the proxy
         #
         self.__elasticsearch__.class.__send__ :include, Elasticsearch::Model::Importing::ClassMethods

elasticsearch-model/lib/elasticsearch/model/proxy.rb

@@ -21,10 +21,10 @@ module Model
     #
     #     article = Article.first
     #
-    #     article.respond_to? :as_indexed_json
+    #     article.respond_to? :index_document
     #     # => false
     #
-    #     article.__elasticsearch__.respond_to?(:as_indexed_json)
+    #     article.__elasticsearch__.respond_to?(:index_document)
     #     # => true
     #
     module Proxy

elasticsearch-model/lib/elasticsearch/model/serializing.rb

@@ -12,11 +12,13 @@ module InstanceMethods
 
         # Serialize the record as a Hash, to be passed to the client.
         #
+        # Re-define this method to customize the serialization.
+        #
         # @return [Hash]
         #
-        # @example
+        # @example Return the model instance as a Hash
         #
-        #     Article.first.__elasticsearch__.as_indexed_json(only: 'title')
+        #     Article.first.__elasticsearch__.as_indexed_json
         #     => {"title"=>"Foo"}
         #
         # @see Elasticsearch::Model::Indexing