validates_presence_of(*attr_names) — ActiveModel::Validations::ClassMethods

validates_presence_of(*attr_names)

Validates that the specified attributes are not blank (as defined by Object#blank?). Happens by default on save. Example:

class Person < ActiveRecord::Base
  validates_presence_of :first_name
end

The first_name attribute must be in the object and it cannot be blank.

If you want to validate the presence of a boolean field (where the real values are true and false), you will want to use

validates_inclusion_of :field_name, :in => [true, false]

This is due to the way Object#blank? handles boolean values:

false.blank? # => true

Configuration options:

:message - A custom error message (default is: “can’t be blank”)
:on - Specifies when this validation is active (default is :save, other options :create, :update)
: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

attr_names rest

Source

# File activemodel/lib/active_model/validations/presence.rb, line 30
      def validates_presence_of(*attr_names)
        configuration = { :message => ActiveRecord::Errors.default_error_messages[:blank], :on => :save }
        configuration.update(attr_names.extract_options!)

        # can't use validates_each here, because it cannot cope with nonexistent attributes,
        # while errors.add_on_empty can
        send(validation_method(configuration[:on]), configuration) do |record|
          record.errors.add_on_blank(attr_names, configuration[:message])
        end
      end

Defined in activemodel/lib/active_model/validations/presence.rb line 30 · View on GitHub · Improve this page · Find usages on GitHub

Defined in ActiveModel::Validations::ClassMethods

Signature

Parameters