mosaaleb / counter-cache

Rails Counter Cache gem.

CounterCache

Counter Cache Rails gem provides an easy way to find and auto-update the number of belonging objects efficiently by caching counters in the parent model.

Motivation

CounterCache is an alternative for using native Rails counter cache.

My motivation behind this gem is an attempt to separate counting objects from belongs_to association. If you prefer counting objects and associations separated, this gem gives you a clear distinction between defining counter caches and its associations.

This gem also tends to encapsulate defining counters on the parent model, rather its belonging, so it's clear which counters are specified in every model.

Getting Started

Prerequisites

Rails > 5

Installation

Add this line to your application's Gemfile:

gem 'counter_cache'

And then execute:

$ bundle

Or install it yourself as:

$ gem install counter_cache

Usage

Adding counter_for macro in Active Record models will generate update associated counters from belongings models.

Ex:

class Invoice < ApplicationRecord
  has_many :line_items
  counter_for :line_items
end

counter_for :line_items assumes the that there is a LineItem model, and it will associate the counters in line_items_count column.

Adding counter columns to parent table

You can either add your counters to your parent table manually. Note: Your column name should end with _count Ex:

counter_for :comments
# column name should be comments_count

Or you can use the custom generator provided by this gem:

rails g counter_cache:add_counters [model name] [counter_for option]
rails g counter_cache:add_counters invoice line_items

This will create a new migration for adding an integer line_items_count column in invoices table with 0 as default value.

Then run rails db:migrate.

• counter_cached_columns will return all the cached columns defined per model:

Invoice.counter_cached_columns
#=> [:line_items]

Using custom counter column name

If you want to use another name, you need to use class_name option passing the original model name

Ex:

class Invoice < ApplicationRecord
  has_many :line_items
  counter_for :items, class_name: :LineItem
end

Conditional counters

class Post < ApplicationRecord
  counter_for :comments
  counter_for :liked_comments, class_name: :Comment, scope: -> { liked? }
end

Roadmap

See the open issues for a list of proposed features

License

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

Tests

The gem is fully tested with minitest You can run the tests with:

rake test

Author

• Muhammad
  • GitHub
  • LinkedIn
  • [email protected]

Contributing

Any contributions you make are greatly appreciated.

1. Fork the Project
2. Create your Feature Branch (git checkout -b feature/AmazingFeature)
3. Commit your Changes (git commit -m 'Add some AmazingFeature')
4. Push to the Branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

counter-cache's Issues

counter caches recalculation

Public API method for recalculating cached_counters:

Ex:

# parent_model.recalculate(:defined_column_name)
invoice.recalculate(:line_items)

Ability to generate migration for adding columns after defining counters

It can be done either with rake task or using the rails generator:

~ rake counter_cache:generate_counter_columns_for Invoice
~ rails db:migrate

this should add whatever counter columns defined in the Invoice model with:

class Invoice < ApplicationRecord
  counter_for :line_items
end