Inspired after reading about Luhn Algorithm (or Modulus 10 Algorithm) article (https://en.wikipedia.org/wiki/Luhn_algorithm) from Wiki, I made this gem to easily validate a variety of identification numbers, for example Social Insurance numbers, or Credit card numbers.

Add this line to your application's Gemfile:

gem 'luhn_algorithm'

And then execute:

$ bundle 

Or install it yourself as:

$ gem install luhn_algorithm 

class Member include ActiveModel::Model

attr_accessor :social_insurance_number validates_luhn_algorithm_of :social_insurance_number end

OR

class Member include ActiveModel::Model

attr_accessor :social_insurance_number validates :social_insurance_number, luhn_algorithm: true end

person = Member.new(social_insurance_number: 'a valid number') person.valid? # => true

You can also pass in a customized message when validating an attribute with Luhn Algorithm, for example

validates_luhn_algorithm_of :social_insurance_number, message: 'is not in the correct format'

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/thukim/luhn_algorithm. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

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

Everyone interacting in the LuhnAlgorithm project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.