https://github.com/ledermann/unread

全体像

├── .gemtags
├── .gitignore
├── .tags
├── .tags_sorted_by_file
├── .travis.yml
├── Gemfile
├── Gemfile.lock
├── MIT-LICENSE
├── README.md
├── Rakefile
├── ci
│   ├── Gemfile-rails-3-0
│   ├── Gemfile-rails-3-1
│   ├── Gemfile-rails-3-2
│   ├── Gemfile-rails-4-0
│   └── Gemfile-rails-4-1
├── lib
│   ├── generators
│   │   └── unread
│   │       └── migration
│   │           ├── migration_generator.rb
│   │           └── templates
│   │               └── migration.rb
│   ├── unread
│   │   ├── base.rb
│   │   ├── read_mark.rb
│   │   ├── readable.rb
│   │   ├── reader.rb
│   │   ├── scopes.rb
│   │   └── version.rb
│   └── unread.rb
├── spec
│   ├── base_spec.rb
│   ├── model
│   │   ├── email.rb
│   │   └── reader.rb
│   ├── read_mark_spec.rb
│   ├── readable_spec.rb
│   ├── spec_helper.rb
│   └── support
│       ├── matchers
│       │   └── perform_queries.rb
│       ├── query_counter.rb
│       └── timecop.rb
└── unread.gemspec

11 directories, 34 files

lib/generators

普通のgenerators

#lib/unread.rb

ActiveRecord::Base.send :include, Unread

lib/unread/*をrequireし最後にActiveRecord::Baseにmixinしている

#lib/unread/base.rb

ActiveRecord::Baseへに追加するクラスメソッドの定義をしている追加されるクラスメソッドは2つ ::acts_as_reader ::acts_as_readable

def acts_as_reader
  ReadMark.belongs_to :user, :class_name => self.to_s

  has_many :read_marks, :dependent => :delete_all, :foreign_key => 'user_id', :inverse_of => :user

  after_create do |user|
    # We assume that a new user should not be tackled by tons of old messages
    # created BEFORE he signed up.
    # Instead, the new user starts with zero unread messages
    (ReadMark.readable_classes || []).each do |klass|
      klass.mark_as_read! :all, :for => user
    end
  end

  include Reader::InstanceMethods
end

def acts_as_readable(options={})
  class_attribute :readable_options

  options.reverse_merge!(:on => :updated_at)
  self.readable_options = options

  has_many :read_marks, :as => :readable, :dependent => :delete_all

  ReadMark.readable_classes ||= []
  ReadMark.readable_classes << self unless ReadMark.readable_classes.include?(self)

  include Readable::InstanceMethods
  extend Readable::ClassMethods
  extend Readable::Scopes
end

モデルに::acts_as_readerが宣言されたときにinclude Reader::InstanceMethodsされ使用できるメソッドが増える仕組みになっている宣言系メソッドの実装はその内部で宣言後に使用可能になるメソッドを定義したmoduleをincludeするパターンが多い

class User < ActiveRecord::Base
  acts_as_reader
end

#lib/unread/reader.rb Reader::InstanceMethodsの実装 #lib/unread/readable.rb Readable::InstanceMethodsとReadable::ClassMethodsの実装 #lib/unread/scopes.rb Readable::Scopesの実装

#lib/read_mark.rb ActiveRecord::Baseを継承するこのgemが追加するテーブルのモデルクラスを定義している

kyuden/unread.md

lib/generators