raihan2006i · May 6, 2019 12:30
diff --git a/Gemfile b/Gemfile
 # ...
 # https://github.com/exAspArk/batch-loader
 gem 'batch-loader'
diff --git a/post.rb b/post.rb
 class Post < ApplicationRecord
  # ...
  
  def get_author_lazily
    BatchLoader.for(self).batch do |posts, batch_loader|
      User.where(:_id.in => posts.pluck(:author_id)).each do |user|
        # Modify the user through a given block, say, for serialization.
        modified_user = block_given? ? yield(user) : user
        batch_loader.call(posts.detect { |p| p.author_id == user._id.to_s }, modified_user)
      end
    end
  end
  # ...
 end
diff --git a/posts_controller.rb b/posts_controller.rb
 class PostsController < ApplicationController
  def index
    # Can't do Post.includes(:author) beacuse the author (User object)
    # is stored in an entirely different database: a MongoDB instance.
    posts = Post.all

    render json: posts
  end
 end
diff --git a/PostSerializer.rb b/PostSerializer.rb
 class PostSerializer < ActiveModel::Serializer
  attributes :id, :title, :details, :author

  def author
    object.get_author_lazily do |author|
      # Serialize the author after it has been loaded.
      ActiveModelSerializers::SerializableResource.new(author).as_json[:user]
    end
  end
  # ...
 end
diff --git a/user.rb b/user.rb
 class User
  include Mongoid::Document
  include Mongoid::Timestamps
  # ...
 end
diff --git a/user_serializer.rb b/user_serializer.rb
 class UserSerializer < ActiveModel::Serializer
  # ....
 end
	# ...
	# https://github.com/exAspArk/batch-loader
	gem 'batch-loader'
	class Post < ApplicationRecord
	# ...

	def get_author_lazily
	BatchLoader.for(self).batch do \|posts, batch_loader\|
	User.where(:_id.in => posts.pluck(:author_id)).each do \|user\|
	# Modify the user through a given block, say, for serialization.
	modified_user = block_given? ? yield(user) : user
	batch_loader.call(posts.detect { \|p\| p.author_id == user._id.to_s }, modified_user)
	end
	end
	end
	# ...
	end
	class PostsController < ApplicationController
	def index
	# Can't do Post.includes(:author) beacuse the author (User object)
	# is stored in an entirely different database: a MongoDB instance.
	posts = Post.all

	render json: posts
	end
	end
	class PostSerializer < ActiveModel::Serializer
	attributes :id, :title, :details, :author

	def author
	object.get_author_lazily do \|author\|
	# Serialize the author after it has been loaded.
	ActiveModelSerializers::SerializableResource.new(author).as_json[:user]
	end
	end
	# ...
	end
	class User
	include Mongoid::Document
	include Mongoid::Timestamps
	# ...
	end