ActiveRecord Callback Analyzer

Arca is a callback analyzer for ActiveRecord like models ideally suited for digging yourself out of callback hell. Arca helps you answer questions like:

• how spread out callbacks are for each model
• how many callbacks use conditionals (:if and :unless)
• how many possible permutations exist per callback type (:commit, :create, :destroy, :find, :initialize, :rollback, :save, :touch, :update, :validation) taking conditionals into consideration

The Arca library has two main components, the collector and the reporter. Include the collector module in each ActiveRecord model you want to analyze and then use the reporter to analyze and present the data.

Usage

Add the gem to your Gemfile and run bundle.

gem 'arca'

In your test helper (test/test_helper.rb for example) require the Arca library and include the Arca::Collector in ActiveRecord::Base.

require "arca"

class ActiveRecord::Base
  include Arca::Collector
end

In this example the Annoucements module is included in Ticket and defines it's own callback.

class Ticket < ActiveRecord::Base
  include Announcements

  before_save :set_title, :set_body
  before_save :upcase_title, :if => :title_is_a_shout?

  def set_title
    self.title ||= "Ticket id #{SecureRandom.hex(2)}"
  end

  def set_body
    self.body ||= "Everything is broken."
  end

  def upcase_title
    self.title = title.upcase
  end

  def title_is_a_shout?
    self.title.split(" ").size == 1
  end
end

module Announcements
  def self.included(base)
    base.class_eval do
      after_save :announce_save
    end
  end

  def announce_save
    puts "saved #{self.class.name.downcase}!"
  end
end

Use Arca[Ticket].report to analyze the callbacks for the Ticket class.

> Arca.root_path = `pwd`.chomp
=> "/Users/jonmagic/Projects/arca"
> Arca[Ticket].report
{
                   :model_name => "Ticket",
              :model_file_path => "test/fixtures/ticket.rb",
              :callbacks_count => 4,
           :conditionals_count => 1,
          :lines_between_count => 6,
     :external_callbacks_count => 1,
       :external_targets_count => 0,
  :external_conditionals_count => 0,
      :calculated_permutations => 2
}
> Arca[Ticket].analyzed_callbacks
{
  :before_save => [
    {
      :callback                       => :before_save,
      :callback_file_path             => "test/fixtures/ticket.rb",
      :callback_line_number           => 5,
      :external_callback              => false,
      :target                         => :set_title,
      :target_file_path               => "test/fixtures/ticket.rb",
      :target_line_number             => 8,
      :external_target                => false,
      :lines_to_target                => 3,
      :conditional                    => nil,
      :conditional_target             => nil,
      :conditional_target_file_path   => nil,
      :conditional_target_line_number => nil,
      :external_conditional_target    => nil,
      :lines_to_conditional_target    => nil
    },
    {
      :callback                       => :before_save,
      :callback_file_path             => "test/fixtures/ticket.rb",
      :callback_line_number           => 5,
      :external_callback              => false,
      :target                         => :set_body,
      :target_file_path               => "test/fixtures/ticket.rb",
      :target_line_number             => 12,
      :external_target                => false,
      :lines_to_target                => 7,
      :conditional                    => nil,
      :conditional_target             => nil,
      :conditional_target_file_path   => nil,
      :conditional_target_line_number => nil,
      :external_conditional_target    => nil,
      :lines_to_conditional_target    => nil
    },
    {
      :callback                       => :before_save,
      :callback_file_path             => "test/fixtures/ticket.rb",
      :callback_line_number           => 6,
      :external_callback              => false,
      :target                         => :upcase_title,
      :target_file_path               => "test/fixtures/ticket.rb",
      :target_line_number             => 16,
      :external_target                => false,
      :lines_to_target                => 10,
      :conditional                    => :if,
      :conditional_target             => :title_is_a_shout?,
      :conditional_target_file_path   => "test/fixtures/ticket.rb",
      :conditional_target_line_number => 20,
      :external_conditional_target    => false,
      :lines_to_conditional_target    => nil
    }
  ],
  :after_save  => [
    {
      :callback                       => :after_save,
      :callback_file_path             => "test/fixtures/announcements.rb",
      :callback_line_number           => 4,
      :external_callback              => true,
      :target                         => :announce_save,
      :target_file_path               => "test/fixtures/announcements.rb",
      :target_line_number             => 8,
      :external_target                => false,
      :lines_to_target                => 4,
      :conditional                    => nil,
      :conditional_target             => nil,
      :conditional_target_file_path   => nil,
      :conditional_target_line_number => nil,
      :external_conditional_target    => nil,
      :lines_to_conditional_target    => nil
    }
  ]
}

License

The MIT License (MIT)

Copyright (c) 2015 Jonathan Hoyt

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.