ActiveModel::Validations::Reflection

ActiveModel::Validations::Reflection extends ActiveModel reflection capabilities on validations.

Installation

ActiveModel::Validations::Reflection is distributed as a gem and available on rubygems.org so you can add it to your Gemfile or install it manually with:

gem install active_model_validations_reflection

Usage

ActiveModel, at least since 3.0, provide a basic mechanism to inspect validations on a model through ActiveModel::Validations::ClassMethods#validators and ActiveModel::Validations::ClassMethods#validators_on.

This extends it with easier filtering on validators on class level and contextual filtering on instance level.

.validators_of_kinds(*kinds) & .validators_on_of_kinds(attribute, *kinds)

.validators_of_kinds & .validators_on_of_kinds are class methods to filter validators by kind, respectively on all or a single attribute.

Any kind supported by validates (:presence , :inclusion, :uniqueness, or custom validator's kind) can be used to filter validators.

class Article < ApplicationRecord
  include ActiveModel::Validations::Reflection
  
  validates :date,
            presence: true,
            timeliness: { type: :date }
end

Article.validators_of_kinds(:presence)
# => [#<ActiveModel::Validations::PresenceValidator […]>]
Article.validators_on_of_kinds(:date, :timeliness)
# => [#<ValidatesTimeliness::Validator […]>]

.flat_validators_of_kinds(*kinds) & .flat_validators_on_of_kinds(attribute, *kinds)

Same as the above two but only return validators without conditions (:if / :unless).

class Article < ApplicationRecord
  include ActiveModel::Validations::Reflection
  
  enum :status, %i[draft published]
  
  validates :date,
            presence: true,
            timeliness: { type: :date, if: :published? }
end

Article.validators_of_kinds(:presence)
# => [#<ActiveModel::Validations::PresenceValidator […]>]
Article.validators_on_of_kinds(:date, :timeliness)
# => []

#relevant_validators(*kinds) & #relevant_validators_on(attribute, *kinds)

Returns validator that will be applied considering the instance current state: flat validators and conditional validators whose condition is met.

class Article < ApplicationRecord
  include ActiveModel::Validations::Reflection
  
  enum :status, %i[draft published]
  
  validates :date,
            presence: true,
            timeliness: { type: :date, if: :published? }
end

article = Article.new
article.relevant_validators
# => [#<ActiveModel::Validations::PresenceValidator […]>]
article.relevant_validators_on(:date)
# => [#<ActiveModel::Validations::PresenceValidator […]>]

article.status = :published
article.relevant_validators_on(:date)
# => [#<ActiveModel::Validations::PresenceValidator […]>, #<ValidatesTimeliness::Validator […]>]

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/notus-sh/active_model_validations_reflection.