rails elastic search relationship attributes not indexed

Question

Basically I got 3 models(Book,Chapter,Author), and I want to include some of the books and author attributes when indexing chapter.

here is my Chapter.rb

class Chapter < ActiveRecord::Base
  belongs_to :book, :counter_cache => true
  include Elasticsearch::Model

  index_name [Rails.env, model_name.collection.gsub(/\//, '-')].join('_')

    mappings  do
      indexes :id, type: :integer
      indexes :title, type: :string
      indexes :description, type: :string
      indexes :content, type: :string
      indexes :updated_at, type: :date # Date example
      indexes :book_title
      indexes :book_type
      indexes :author_name
      indexes :book_id
    end

  def book_title
    book.title
  end
  def book_type
    book.book_type
  end
  def author_name
   " #{book.author.firstname} #{book.author.lastname} "
  end

  def to_indexed_json
    to_json methods: [:book_title, :book_type, :author_name]
  end
end

http://localhost:9200/development_chapters/_mapping?pretty shows correct mapping

{
  "development_chapters" : {
    "mappings" : {
      "chapter" : {
        "properties" : {
          "author_name" : {
            "type" : "string"
          },
          "book_title" : {
            "type" : "string"
          },....
        }
      }
    }
  }
}

Then why do I not get author_name, book_title etc... in the search results

<Elasticsearch::Model::Response::Result:0x00000105e393a0 @result=#<Hashie::Mash _id="415" _index="development_chapters" _score=1.0 _source=#<Hashie::Mash book_id=153 content="[\"Explicabo accusantium odit .\"]" created_at="2015-04-22T18:43:58.586Z" description="You can't generate the application without quantifying the cross-platform SDD bandwidth!" id=415 title="Future Communications Orchestrator" updated_at="2015-04-22T18:43:58.586Z"> _type="chapter">>

Answer 1

You are defining wrong serialization method. Elasticsearch::Model searches for method as_indexed_json and you are defining to_indexed_json. In elasticesearch-model gem you can find examples https://github.com/elastic/elasticsearch-rails/blob/master/elasticsearch-model/examples/activerecord_associations.rb#L82

It should look something like this:

def as_indexed_json(options = {})
  as_json methods: [:book_title, :book_type, :author_name]
end