instance method `validate`

Ruby on Rails 4.0.13

Since v3.0.20

Available in: v3.0.20 v3.1.12 v3.2.22.5 v4.0.13 v4.1.16 v4.2.9 v5.2.8.1 v6.0.6 v6.1.7.10 v7.0.10 v7.1.6 v7.2.3 v8.0.4 v8.1.2

Compare with:

validate(*args, &block)

Adds a validation method or block to the class. This is useful when overriding the validate instance method becomes too unwieldy and you’re looking for more descriptive declaration of your validations.

This can be done with a symbol pointing to a method:

class Comment
  include ActiveModel::Validations

  validate :must_be_friends

  def must_be_friends
    errors.add(:base, 'Must be friends to leave a comment') unless commenter.friend_of?(commentee)
  end
end

With a block which is passed with the current record to be validated:

class Comment
  include ActiveModel::Validations

  validate do |comment|
    comment.must_be_friends
  end

  def must_be_friends
    errors.add(:base, 'Must be friends to leave a comment') unless commenter.friend_of?(commentee)
  end
end

Or with a block where self points to the current record to be validated:

class Comment
  include ActiveModel::Validations

  validate do
    errors.add(:base, 'Must be friends to leave a comment') unless commenter.friend_of?(commentee)
  end
end

Options:

:on - Specifies the context where this validation is active (e.g. on: :create or on: :custom_validation_context)
:allow_nil - Skip validation if attribute is nil.
:allow_blank - Skip validation if attribute is blank.
:if - Specifies a method, proc or string to call to determine if the validation should occur (e.g. if: :allow_validation, or if: Proc.new { |user| user.signup_step > 2 }). The method, proc or string should return or evaluate to a true or false value.
:unless - Specifies a method, proc or string to call to determine if the validation should not occur (e.g. unless: :skip_validation, or unless: Proc.new { |user| user.signup_step <= 2 }). The method, proc or string should return or evaluate to a true or false value.

Parameters

args rest
block block

Source

# File activemodel/lib/active_model/validations.rb, line 140
      def validate(*args, &block)
        options = args.extract_options!
        if options.key?(:on)
          options = options.dup
          options[:if] = Array(options[:if])
          options[:if].unshift("validation_context == :#{options[:on]}")
        end
        args << options
        set_callback(:validate, *args, &block)
      end

Defined in activemodel/lib/active_model/validations.rb line 140 · View on GitHub · Improve this page · Find usages on GitHub

Defined in ActiveModel::Validations::ClassMethods

Signature

Parameters