Method: ActiveModel::Validations::HelperMethods#validates_exclusion_of

Defined in:
lib/active_model/validations/exclusion.rb

#validates_exclusion_of(*attr_names) ⇒ Object

Validates that the value of the specified attribute is not in a particular enumerable object.

class Person < ActiveRecord::Base
  validates_exclusion_of :username, :in => %w( admin superuser ), :message => "You don't belong here"
  validates_exclusion_of :age, :in => 30..60, :message => "This site is only for under 30 and over 60"
  validates_exclusion_of :format, :in => %w( mov avi ), :message => "extension %{value} is not allowed"
end

Configuration options:

  • :in - An enumerable object of items that the value shouldn’t be part of.

  • :message - Specifies a custom error message (default is: “is reserved”).

  • :allow_nil - If set to true, skips this validation if the attribute is nil (default is false).

  • :allow_blank - If set to true, skips this validation if the attribute is blank (default is false).

  • :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.



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# File 'lib/active_model/validations/exclusion.rb', line 38

def validates_exclusion_of(*attr_names)
  validates_with ExclusionValidator, _merge_attributes(attr_names)
end