Gargron / counter_cache-rails

ActiveRecord child records counter caching on your rails application cache store.

CounterCacheRails

ActiveRecord child records counter caching on your rails application cache store.

Installation

Add this line to your rails application's Gemfile:

gem 'counter_cache-rails'

Usage

class Post
  has_many :comments

  counter_cache :comments,
                if: ->(comment) { comment.visible? },
                scope: ->(comments) { comments.visible }

  after_update_comments_count do
    # you can use callbacks on update counter cache
  end

  after_increment_comments_count do
    Redis.current.increment('service:total:comments')
  end

  after_decrement_comments_count do
    Redis.current.decrement('service:total:comments')
  end

  after_cache_comments_count do
    update(comments_count: comments_count)
  end
end

class Comment
  belong_to :post
end

post = Post.create(title: 'sample title', body: 'post body')
post.comments_count # => 0

post.comments.create(body: 'comment body')
post.comments_count # => 1

post.comments_count(force: true) # force reload counter cache

License

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