HasCounterOn

ActiveRecord counter_cache has been reborn, with ability to specify conditions. Inspired by counter_cache_with_conditions gem.

Installation

To use it, add it to your Gemfile:

gem 'has_counter_on'

and bundle:

$ bundle install

After Installation

Install migrations

rake has_counter_on:setup

Review the generated migrations then migrate:

rake db:migrate

Usage

Let's say you have a User model and an Article model.

class User < ActiveRecord::Base
  has_many :articles
  has_many :published_articles, -> { where(has_published: true) }, class_name: :Article
end

class Article < ActiveRecord::Base
  belongs_to :user
end

By using ActiveRecord's counter_cache, articles_count can be created as follows: (However, you cannot handle published_articles_count)

class User < ActiveRecord::Base
  has_many :articles
  has_many :published_articles, -> { where(has_published: true) }, class_name: :Article
end

class Article < ActiveRecord::Base
  belongs_to :user, counter_cache: true
end

with has_counter_on, you can handle both of counters like this:

class User < ActiveRecord::Base
  has_many :articles
  has_many :published_articles, -> { where(has_published: true) }, class_name: :Article

  has_counter_on :articles
  has_counter_on :articles, :published_articles_count, has_published: true
end

class Article < ActiveRecord::Base
  belongs_to :user
end

Each counter will be updated automatically like that of the ActiveRecord.

Complex Conditions

Complex conditions can be expressed as lambda.

class User < ActiveRecord::Base
  has_many :articles
  has_many :published_articles, -> { where.not(published_at: nil) }, class_name: :Article

  has_counter_on :articles
  has_counter_on :articles, :published_articles_count, published_at: -> (value) { value.present? }
end

class Article < ActiveRecord::Base
  belongs_to :user
end

Of course, multiple conditions are available.

class User < ActiveRecord::Base
  has_counter_on :articles, :featured_articles_count, has_featured: true, has_published: true
end

Contributing

Bug reports and pull requests are welcome on GitHub.

License

The gem is available as open source under the terms of the MIT License.