instance method `validates`

Ruby on Rails 3.0.20

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:

validates(*attributes)

This method is a shortcut to all default validators and any custom validator classes ending in ‘Validator’. Note that Rails default validators can be overridden inside specific classes by creating custom validator classes in their place such as PresenceValidator.

Examples of using the default rails validators:

validates :terms, :acceptance => true
validates :password, :confirmation => true
validates :username, :exclusion => { :in => %w(admin superuser) }
validates :email, :format => { :with => /\A([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})\Z/i, :on => :create }
validates :age, :inclusion => { :in => 0..9 }
validates :first_name, :length => { :maximum => 30 }
validates :age, :numericality => true
validates :username, :presence => true
validates :username, :uniqueness => true

The power of the validates method comes when using custom validators and default validators in one call for a given attribute e.g.

class EmailValidator < ActiveModel::EachValidator
  def validate_each(record, attribute, value)
    record.errors[attribute] << (options[:message] || "is not an email") unless
      value =~ /\A([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})\z/i
  end
end

class Person
  include ActiveModel::Validations
  attr_accessor :name, :email

  validates :name, :presence => true, :uniqueness => true, :length => { :maximum => 100 }
  validates :email, :presence => true, :email => true
end

Validator classes may also exist within the class being validated allowing custom modules of validators to be included as needed e.g.

class Film
  include ActiveModel::Validations

  class TitleValidator < ActiveModel::EachValidator
    def validate_each(record, attribute, value)
      record.errors[attribute] << "must start with 'the'" unless value =~ /\Athe/i
    end
  end

  validates :name, :title => true
end

The validators hash can also handle regular expressions, ranges and arrays:

validates :email, :format => /@/
validates :gender, :inclusion => %w(male female)
validates :password, :length => 6..20

Finally, the options :if, :unless, :on, :allow_blank and :allow_nil can be given to one specific validator:

validates :password, :presence => { :if => :password_required? }, :confirmation => true

Or to all at the same time:

validates :password, :presence => true, :confirmation => true, :if => :password_required?

Parameters

attributes rest

Source

# File activemodel/lib/active_model/validations/validates.rb, line 73
      def validates(*attributes)
        defaults = attributes.extract_options!
        validations = defaults.slice!(:if, :unless, :on, :allow_blank, :allow_nil)

        raise ArgumentError, "You need to supply at least one attribute" if attributes.empty?
        raise ArgumentError, "Attribute names must be symbols" if attributes.any?{ |attribute| !attribute.is_a?(Symbol) }
        raise ArgumentError, "You need to supply at least one validation" if validations.empty?

        defaults.merge!(:attributes => attributes)

        validations.each do |key, options|
          begin
            validator = const_get("#{key.to_s.camelize}Validator")
          rescue NameError
            raise ArgumentError, "Unknown validator: '#{key}'"
          end

          validates_with(validator, defaults.merge(_parse_validates_options(options)))
        end
      end

Defined in activemodel/lib/active_model/validations/validates.rb line 73 · View on GitHub · Improve this page · Find usages on GitHub

Defined in ActiveModel::Validations::ClassMethods

Signature

Parameters