karmi · July 29, 2012 16:57 · Jul 29, 2012
diff --git a/active_record_associations.rb b/active_record_associations.rb
@@ -0,0 +1,141 @@
+# An example of elasticsearch & Tire setup for ActiveRecord associations.
+#
+# A `Book has_many :chapters` scenario, with mapping and JSON serialization
+# for indexing associated models.
+#
+# Demonstrates three important caveats as of now:
+#
+# 1. You you have to use `touch: true` in the `belongs_to` declaration,
+#    to automatically notify the parent model about the update.
+#
+# 2. You have to explicitely hook up updating elasticsearch index via
+#    the `after_touch` callback in the parent model.
+#
+# 3. You have to disable `include_root_in_json` for proper JSON serialization.
+#
+#
+# Run me with:
+#
+#     $ ruby active_record_associations.rb 
+#
+
+require 'logger'
+require 'ansi/core'
+require 'active_record'
+require 'oj'
+require 'tire'
+
+def _(message=nil); puts '-'*80, ANSI.bold(message.to_s), '-'*80; end
+
+ActiveRecord::Base.logger = Logger.new(STDERR)
+ActiveRecord::Base.establish_connection( adapter: 'sqlite3', database: ":memory:" )
+
+Tire.configure { logger STDERR }
+
+_ "Creating ActiveRecord schema..."
+
+ActiveRecord::Schema.define(version: 1) do
+  create_table :books do |t|
+    t.string   :title
+    t.timestamps
+  end
+  create_table :chapters do |t|
+    t.string   :text
+    t.integer  :number, :book_id
+    t.timestamps
+  end
+  add_index(:chapters, :book_id)
+end
+
+_ "Deleting elasticsearch index..."
+
+Tire.index('books').delete
+
+# The Book class
+#
+class Book < ActiveRecord::Base
+  has_many :chapters
+
+  # !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+  # Enable automatic saving in elasticsearch when associated objects change
+  #
+  after_touch() { tire.update_index }
+  #
+  # !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+
+  # !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+  # Properly serialize JSON for elasticsearch
+  #
+  self.include_root_in_json = false
+  # !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+
+  include Tire::Model::Search
+  include Tire::Model::Callbacks
+
+  # Define the mapping
+  #
+  mapping do
+    indexes :title,      type: 'string', boost: 10, analyzer: 'snowball'
+    indexes :created_at, type: 'date'
+
+    indexes :chapters do
+      indexes :text, analyzer: 'snowball'
+    end
+  end
+
+  # Define the JSON serialization
+  #
+  def to_indexed_json
+    to_json( include: { chapters: { only: [:text] } } )
+  end
+
+end
+
+# The book Chapter class
+#
+class Chapter < ActiveRecord::Base
+  # !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+  # Do not forget to automatically `touch` parent object from associations
+  belongs_to :book, touch: true
+  # !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+end
+
+_ "Create book instance..."
+
+book = Book.create   title: "How to impress your Rails friends with elasticsearch"
+book.chapters.create number: 1, text: "The world generates more and more information ..."
+book.chapters.create number: 2, text: "After the elasticsearch installation ..."
+
+p Book.first
+p Book.first.chapters
+
+_ "Refresh the index for immediate search (there's a 1 second delay by default)..."
+
+Book.tire.index.refresh
+
+_ "Search 'elasticsearch' in book titles..."
+
+results = Book.search('title:elasticsearch')
+
+puts ANSI.green( "Found: '%s'" % results.first.title )
+
+_ "Search 'install' in chapter text..."
+
+results = Book.search('chapters.text:install')
+
+puts ANSI.green( "Found: '%s'" % results.first.title )
+
+_ "Search 'elasticsearch' anywhere with highlighting..."
+
+results = Book.search do
+  query { string "elasticsearch" }
+  highlight 'title', 'chapters.text'
+end
+
+puts ANSI.green( "Found: '%s'" % results.first.title ),
+     '-'*80,
+     "Highlights: ",
+     results.first.highlight.to_hash              \
+      .map { |k,v| '  - ' + k.to_s + ": " + v.first.to_s } \
+      .map { |s|   s.gsub(/<em>([^<]+)<\/em>/, ANSI.yellow + ANSI.bold + '\1' + ANSI.reset) } \
+      .join("\n")
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