[MODEL] Added example with ActiveRecord associations ("relationships")

This example demonstrates how to set up models, search integration,
callbacks, etc. in a more complex schema.

Author: karmi

Diff for: elasticsearch-model/examples/activerecord_associations.rb

@@ -0,0 +1,153 @@
+# ActiveRecord associations and Elasticsearch
+# ===========================================
+#
+# https://github.com/rails/rails/tree/master/activerecord
+# http://guides.rubyonrails.org/association_basics.html
+
+$LOAD_PATH.unshift File.expand_path('../../lib', __FILE__)
+
+require 'pry'
+Pry.config.history.file = File.expand_path('../../tmp/elasticsearch_development.pry', __FILE__)
+
+require 'logger'
+require 'ansi/core'
+require 'active_record'
+
+require 'elasticsearch/model'
+
+ActiveRecord::Base.logger = ActiveSupport::Logger.new(STDOUT)
+ActiveRecord::Base.establish_connection( adapter: 'sqlite3', database: ":memory:" )
+
+# ----- Schema definition -------------------------------------------------------------------------
+
+ActiveRecord::Schema.define(version: 1) do
+  create_table :categories do |t|
+    t.string     :title
+    t.timestamps
+  end
+
+  create_table :authors do |t|
+    t.string     :first_name, :last_name
+    t.timestamps
+  end
+
+  create_table :authorships do |t|
+    t.references :article
+    t.references :author
+    t.timestamps
+  end
+
+  create_table :articles do |t|
+    t.string   :title
+    t.timestamps
+  end
+
+  create_table :articles_categories, id: false do |t|
+    t.references :article, :category
+  end
+
+  create_table :comments do |t|
+    t.string     :text
+    t.references :article
+    t.timestamps
+  end
+  add_index(:comments, :article_id)
+end
+
+# ----- Model definitions -------------------------------------------------------------------------
+
+class Category < ActiveRecord::Base
+  has_and_belongs_to_many :articles
+end
+
+class Author < ActiveRecord::Base
+  has_many :authorships
+
+  def full_name
+    [first_name, last_name].compact.join(' ')
+  end
+end
+
+class Authorship < ActiveRecord::Base
+  belongs_to :author
+  belongs_to :article, touch: true
+end
+
+class Article < ActiveRecord::Base
+  has_and_belongs_to_many :categories, after_add:    [ lambda { |a,c| a.__elasticsearch__.index_document } ],
+                                       after_remove: [ lambda { |a,c| a.__elasticsearch__.index_document } ]
+  has_many                :authorships
+  has_many                :authors, through: :authorships
+  has_many                :comments
+end
+
+class Comment < ActiveRecord::Base
+  belongs_to :article, touch: true
+end
+
+# ----- Search integration ------------------------------------------------------------------------
+
+module Searchable
+  extend ActiveSupport::Concern
+
+  included do
+    include Elasticsearch::Model
+    include Elasticsearch::Model::Callbacks
+
+    __elasticsearch__.client Elasticsearch::Client.new log: true
+    __elasticsearch__.client.transport.logger.formatter = proc { |s, d, p, m| "\e[32m#{m}\n\e[0m" }
+
+    include Indexing
+    after_touch() { __elasticsearch__.index_document }
+  end
+
+  module Indexing
+
+    # Customize the JSON serialization for Elasticsearch
+    def as_indexed_json(options={})
+      self.as_json(
+        include: { categories: { only: :title},
+                   authors:    { methods: [:full_name], only: [:full_name] },
+                   comments:   { only: :text }
+                 })
+    end
+  end
+end
+
+Article.__send__ :include, Searchable
+
+# ----- Insert data -------------------------------------------------------------------------------
+
+# Create category
+#
+category = Category.create title: 'One'
+
+# Create author
+#
+author = Author.create first_name: 'John', last_name: 'Smith'
+
+# Create article
+
+article  = Article.create title: 'First Article'
+
+# Assign category
+#
+article.categories << category
+
+# Assign author
+#
+article.authors << author
+
+# Add comment
+#
+article.comments.create text: 'First comment'
+
+# Load
+#
+article = Article.all.includes(:categories, :authors, :comments).first
+
+# ----- Pry ---------------------------------------------------------------------------------------
+
+Pry.start(binding, prompt: lambda { |obj, nest_level, _| '> ' },
+                   input: StringIO.new('puts "\n\narticle.as_indexed_json\n"; article.as_indexed_json'),
+                   quiet: true)