dealing with concerns

Taking care of concerns, my views are

They are meant not to have large/GOD classes

They are not specific to ActiveRecord

They are there to help us out find out dependencies easier

They should not be dependent on each other, if module A has concern :b, then there should exist paths “root/a.rb” and “/root/a/b.rb“. Though this we ourself have to make sure about concerns path by writing additional code at initialization

I always willing to write clean and neat code, and have end up maintaining my concerns the following ways

1. Reopening Class
2. Include Module
3. Extend ActiveSupport::Concern

I do have one doubt though, out of 3 approaches, which one is good for faster execution?

	# config/initializers/concerns.rb
	class << ActiveRecord::Base
	def concerned_with(*concerns)
	concerns.each do |concern|
	require_dependency "#{name.underscore}/#{concern}"
	klass = concern.to_s.classify.constantize rescue nil
	send(:include, klass) if klass.is_a? Module
	end
	end
	end
	# Approach #1 opening User class
	# app/models/user/validations.rb
	class User << ActiveRecord::Base
	validates :mobile, :length => { :in => 6..20 }, :allow_blank => true, :allow_nil => true
	validates_presence_of :country, :name
	before_create :is_zip_validated_by_yahoo?
	# and so on
	end
	# Approach #2 Let User include module
	# app/models/user/module_name.rb
	module ModuleName
	def blah_blah_blah
	end # and so on ….
	end
	# Approach #3 extend ActiveSupport::Concern
	# app/models/user/ensure_something_type.rb
	module EnsureSomethingType
	extend ActiveSupport::Concern
	included do
	before_create :ensure_something_type
	belongs_to :something_type
	has_one :something_base_type, :through => :something_type
	end
	def ensure_something_type
	self.something_type ||= SomethingType.find_by_name("something something")
	end
	end
	# app/models/user.rb
	concerned_with  :validations,
	:data_uploader,
	:ensure_something_type,
	:jingo_filters,
	:macro_reports,
	:pricing,

view raw

concerns.rb

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