Scrooge

Make it easy to store money values in an ActiveRecord model, avoiding the annoying floating point math. The idea is to store the monetary values as the amount of cents in the database to avoid the math.

class Product < ActiveRecord::Base
  attr_cents :price
end

product = Product.new(:price => 10.99)
product.price #=> #<Scrooge::Money @cents="1099">

The Scrooge::Money objects will act as a Numeric in all regards, so you can do math with other numbers easily.

The products table should have an integer column price_in_cents for this to work.

Calculations

---

If you need aggregated calculations on your model, you can use the provided method Numeric#as_cents, which converts a number to a Scrooge::Money instance, assuming that the number is already the number of cents. For example:

class Sale < ActiveRecord::Base
  belongs_to :product
  attr_cents :value
end

class Product < ActiveRecord::Base
  has_many :sales

  def gross_sales
    sales.sum(:value_in_cents).as_cents
  end
end

product = Product.create
product.sales.create(:value => 20)
product.sales.create(:value => 20.5)
product.sales.create(:value => 25)

product.gross_sales #=> #<Scrooge::Money @cents="6550">
product.gross_sales == 65.5 #=> true

Why?

Because we only needed this, and most of the gems that do this stuff are too damn big and have a ton of un-needed functionality.

Install

gem install scrooge

Then, in order to require it, if you want the ActiveRecord helper methods:

require "scrooge/active_record"

Or:

config.gem "scrooge"

License

(The MIT License)

Copyright © 2010 Nicolas Sanguinetti, nicolassanguinetti.info

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.