Permalink
Fetching contributors…
Cannot retrieve contributors at this time
144 lines (127 sloc) 4.79 KB
module Elasticsearch
module Model
# This module provides a proxy interfacing between the including class and
# {Elasticsearch::Model}, preventing the pollution of the including class namespace.
#
# The only "gateway" between the model and Elasticsearch::Model is the
# `__elasticsearch__` class and instance method.
#
# The including class must be compatible with
# [ActiveModel](https://github.com/rails/rails/tree/master/activemodel).
#
# @example Include the {Elasticsearch::Model} module into an `Article` model
#
# class Article < ActiveRecord::Base
# include Elasticsearch::Model
# end
#
# Article.__elasticsearch__.respond_to?(:search)
# # => true
#
# article = Article.first
#
# article.respond_to? :index_document
# # => false
#
# article.__elasticsearch__.respond_to?(:index_document)
# # => true
#
module Proxy
# Define the `__elasticsearch__` class and instance methods in the including class
# and register a callback for intercepting changes in the model.
#
# @note The callback is triggered only when `Elasticsearch::Model` is included in the
# module and the functionality is accessible via the proxy.
#
def self.included(base)
base.class_eval do
# {ClassMethodsProxy} instance, accessed as `MyModel.__elasticsearch__`
#
def self.__elasticsearch__ &block
@__elasticsearch__ ||= ClassMethodsProxy.new(self)
@__elasticsearch__.instance_eval(&block) if block_given?
@__elasticsearch__
end
# {InstanceMethodsProxy}, accessed as `@mymodel.__elasticsearch__`
#
def __elasticsearch__ &block
@__elasticsearch__ ||= InstanceMethodsProxy.new(self)
@__elasticsearch__.instance_eval(&block) if block_given?
@__elasticsearch__
end
# Register a callback for storing changed attributes for models which implement
# `before_save` method and return changed attributes (ie. when `Elasticsearch::Model` is included)
#
# @see http://api.rubyonrails.org/classes/ActiveModel/Dirty.html
#
before_save do |i|
if i.class.instance_methods.include?(:changes_to_save) # Rails 5.1
a = i.__elasticsearch__.instance_variable_get(:@__changed_model_attributes) || {}
i.__elasticsearch__.instance_variable_set(:@__changed_model_attributes,
a.merge(Hash[ i.changes_to_save.map { |key, value| [key, value.last] } ]))
elsif i.class.instance_methods.include?(:changes)
a = i.__elasticsearch__.instance_variable_get(:@__changed_model_attributes) || {}
i.__elasticsearch__.instance_variable_set(:@__changed_model_attributes,
a.merge(Hash[ i.changes.map { |key, value| [key, value.last] } ]))
end
end if respond_to?(:before_save)
end
end
# @overload dup
#
# Returns a copy of this object. Resets the __elasticsearch__ proxy so
# the duplicate will build its own proxy.
def initialize_dup(_)
@__elasticsearch__ = nil
super
end
# Common module for the proxy classes
#
module Base
attr_reader :target
def initialize(target)
@target = target
end
# Delegate methods to `@target`
#
def method_missing(method_name, *arguments, &block)
target.respond_to?(method_name) ? target.__send__(method_name, *arguments, &block) : super
end
# Respond to methods from `@target`
#
def respond_to?(method_name, include_private = false)
target.respond_to?(method_name) || super
end
def inspect
"[PROXY] #{target.inspect}"
end
end
# A proxy interfacing between Elasticsearch::Model class methods and model class methods
#
# TODO: Inherit from BasicObject and make Pry's `ls` command behave?
#
class ClassMethodsProxy
include Base
end
# A proxy interfacing between Elasticsearch::Model instance methods and model instance methods
#
# TODO: Inherit from BasicObject and make Pry's `ls` command behave?
#
class InstanceMethodsProxy
include Base
def klass
target.class
end
def class
klass.__elasticsearch__
end
# Need to redefine `as_json` because we're not inheriting from `BasicObject`;
# see TODO note above.
#
def as_json(options={})
target.as_json(options)
end
end
end
end
end