Working with active records in rails is nice because a lot of your domain is directly represented in your model classes.

Sometimes however, you still need to create some domain classes that aren’t tied to a database model, and reference them in your app.

I’m not sure what the best way (or convention) is for doing this, but what’s been working for me is to create a separate directory called domain

and place my domain object(s) in there:

class TimeRange
  def self.today
    (Time.now.midnight)..Time.now.end_of_day
  end

  def self.yesterday
    (Time.now.midnight - 1.day)..Time.now.end_of_day
  end

  def self.last_week
    (Time.now.prev_week)..Time.now.end_of_day
  end

  def self.ages_ago
    (Time.now.prev_year)..Time.now.end_of_day
  end
end

And then referencing them where I need them using the ‘require_relative’ command.

require_relative '../domain/time_range'
require_relative '../domain/constants'

class CitiesController < ApplicationController