RailsModelValidator

Rails validates_* DSL with complex if:, unless: and on: conditions becomes ugly very quick. This micro gem introduces base PORO class which aims to replace standard Rails DSL and still allows to use default ActiveModel validations for individual checks.

Installation

Add this line to your application's Gemfile:

gem 'rails_model_validator'

And then execute:

$ bundle

Or install it yourself as:

$ gem install rails_model_validator

Usage

The following piece of code:

class User < ApplicationRecord
  validate :subject_essential_attributes_present,   on: :update, if: :move_to_open_status?
  validate :essential_attributes_present,           on: :update, if: :move_to_open_status?
  validate :reviewed_attributes_present,            on: :update, if: :move_to_review_required_status?
  validate :creator_email_present, on: :update,                  if: :closing?

  # ... 15+ lines

  def subject_essential_attributes_present
    errors.add(:name, :invalid) if name.to_s.blank?
    # ... 20+ lines
  end
end

May be transformed into one or several simple, clean and reusable classes:

class SubjectEssentialAttributesValidator < RailsModelValidator
  def validate
    validate_personal_attributes_present
    validate_there_are_not_too_much_images
  end

  private

  def validate_personal_attributes_present
    validate_presence_of(:name, :age, :gender)
  end

  def validate_there_are_not_too_much_images
    errors.add(:images, :too_many) if subject.images.count > 10
  end
end

class User < ApplicationRecord
  validate { SubjectEssentialAttributesValidator.validate(self) }
end

Rails custom validators are the way to go as well, but they tend to be little more verbose.

If you have really complex validations, check: tram-policy.

Base class also provides #create? and #update? methods which will work in ActiveRecord context.

Development

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.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/[USERNAME]/rails_model_validator. 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.

License

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

Code of Conduct

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

gzigzigzeo / rails_model_validator