Module: ActiveModel::Validations::HelperMethods

Defined in:
lib/active_model/validations/with.rb,
lib/active_model/validations/format.rb,
lib/active_model/validations/length.rb,
lib/active_model/validations/presence.rb,
lib/active_model/validations/exclusion.rb,
lib/active_model/validations/inclusion.rb,
lib/active_model/validations/acceptance.rb,
lib/active_model/validations/confirmation.rb,
lib/active_model/validations/numericality.rb

Instance Method Summary collapse

Instance Method Details

#validates_acceptance_of(*attr_names) ⇒ Object

Encapsulates the pattern of wanting to validate the acceptance of a terms of service check box (or similar agreement). Example:

class Person < ActiveRecord::Base
  validates_acceptance_of :terms_of_service
  validates_acceptance_of :eula, :message => "must be abided"
end

If the database column does not exist, the terms_of_service attribute is entirely virtual. This check is performed only if terms_of_service is not nil and by default on save.

Configuration options:

  • :message - A custom error message (default is: “must be accepted”).

  • :on - Specifies when this validation is active. Runs in all validation contexts by default (nil), other options are :create and :update.

  • :allow_nil - Skip validation if attribute is nil (default is true).

  • :accept - Specifies value that is considered accepted. The default value is a string “1”, which makes it easy to relate to an HTML checkbox. This should be set to true if you are validating a database column, since the attribute is typecast from “1” to true before validation.

  • :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 (for example, :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/acceptance.rb', line 61

def validates_acceptance_of(*attr_names)
  validates_with AcceptanceValidator, _merge_attributes(attr_names)
end

#validates_confirmation_of(*attr_names) ⇒ Object

Encapsulates the pattern of wanting to validate a password or email address field with a confirmation. For example:

Model:
  class Person < ActiveRecord::Base
    validates_confirmation_of :user_name, :password
    validates_confirmation_of :email_address,
                              :message => "should match confirmation"
  end

View:
  <%= password_field "person", "password" %>
  <%= password_field "person", "password_confirmation" %>

The added password_confirmation attribute is virtual; it exists only as an in-memory attribute for validating the password. To achieve this, the validation adds accessors to the model for the confirmation attribute.

NOTE: This check is performed only if password_confirmation is not nil, and by default only on save. To require confirmation, make sure to add a presence check for the confirmation attribute:

validates_presence_of :password_confirmation, :if => :password_changed?

Configuration options:

  • :message - A custom error message (default is: “doesn’t match confirmation”).

  • :on - Specifies when this validation is active. Runs in all validation contexts by default (nil), other options are :create and :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.



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# File 'lib/active_model/validations/confirmation.rb', line 61

def validates_confirmation_of(*attr_names)
  validates_with ConfirmationValidator, _merge_attributes(attr_names)
end

#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"
  validates_exclusion_of :password, :in => lambda { |p| [p.username, p.first_name] }, :message => "should not be the same as your username or first name"
end

Configuration options:

  • :in - An enumerable object of items that the value shouldn’t be part of. This can be supplied as a proc or lambda which returns an enumerable. If the enumerable is a range the test is performed with Range#cover? (backported in Active Support for 1.8), otherwise with include?.

  • :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).

  • :on - Specifies when this validation is active. Runs in all validation contexts by default (nil), other options are :create and :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.



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# File 'lib/active_model/validations/exclusion.rb', line 62

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

#validates_format_of(*attr_names) ⇒ Object

Validates whether the value of the specified attribute is of the correct form, going by the regular expression provided. You can require that the attribute matches the regular expression:

class Person < ActiveRecord::Base
  validates_format_of :email, :with => /\A([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})\Z/i, :on => :create
end

Alternatively, you can require that the specified attribute does not match the regular expression:

class Person < ActiveRecord::Base
  validates_format_of :email, :without => /NOSPAM/
end

You can also provide a proc or lambda which will determine the regular expression that will be used to validate the attribute

class Person < ActiveRecord::Base
  # Admin can have number as a first letter in their screen name
  validates_format_of :screen_name, :with => lambda{ |person| person.admin? ? /\A[a-z0-9][a-z0-9_\-]*\Z/i : /\A[a-z][a-z0-9_\-]*\Z/i }
end

Note: use \A and \Z to match the start and end of the string, ^ and $ match the start/end of a line.

You must pass either :with or :without as an option. In addition, both must be a regular expression or a proc or lambda, or else an exception will be raised.

Configuration options:

  • :message - A custom error message (default is: “is invalid”).

  • :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).

  • :with - Regular expression that if the attribute matches will result in a successful validation. This can be provided as a proc or lambda returning regular expression which will be called at runtime.

  • :without - Regular expression that if the attribute does not match will result in a successful validation. This can be provided as a proc or lambda returning regular expression which will be called at runtime.

  • :on - Specifies when this validation is active. Runs in all validation contexts by default (nil), other options are :create and :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.



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# File 'lib/active_model/validations/format.rb', line 87

def validates_format_of(*attr_names)
  validates_with FormatValidator, _merge_attributes(attr_names)
end

#validates_inclusion_of(*attr_names) ⇒ Object

Validates whether the value of the specified attribute is available in a particular enumerable object.

class Person < ActiveRecord::Base
  validates_inclusion_of :gender, :in => %w( m f )
  validates_inclusion_of :age, :in => 0..99
  validates_inclusion_of :format, :in => %w( jpg gif png ), :message => "extension %{value} is not included in the list"
  validates_inclusion_of :states, :in => lambda{ |person| STATES[person.country] }
end

Configuration options:

  • :in - An enumerable object of available items. This can be supplied as a proc or lambda which returns an enumerable. If the enumerable is a range the test is performed with Range#cover? (backported in Active Support for 1.8), otherwise with include?.

  • :message - Specifies a custom error message (default is: “is not included in the list”).

  • :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).

  • :on - Specifies when this validation is active. Runs in all validation contexts by default (nil), other options are :create and :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.



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# File 'lib/active_model/validations/inclusion.rb', line 62

def validates_inclusion_of(*attr_names)
  validates_with InclusionValidator, _merge_attributes(attr_names)
end

#validates_length_of(*attr_names) ⇒ Object Also known as: validates_size_of

Validates that the specified attribute matches the length restrictions supplied. Only one option can be used at a time:

class Person < ActiveRecord::Base
  validates_length_of :first_name, :maximum => 30
  validates_length_of :last_name, :maximum => 30, :message => "less than 30 if you don't mind"
  validates_length_of :fax, :in => 7..32, :allow_nil => true
  validates_length_of :phone, :in => 7..32, :allow_blank => true
  validates_length_of :user_name, :within => 6..20, :too_long => "pick a shorter name", :too_short => "pick a longer name"
  validates_length_of :zip_code, :minimum => 5, :too_short => "please enter at least 5 characters"
  validates_length_of :smurf_leader, :is => 4, :message => "papa is spelled with 4 characters... don't play me."
  validates_length_of :essay, :minimum => 100, :too_short => "Your essay must be at least 100 words.", :tokenizer => lambda { |str| str.scan(/\w+/) }
end

Configuration options:

  • :minimum - The minimum size of the attribute.

  • :maximum - The maximum size of the attribute.

  • :is - The exact size of the attribute.

  • :within - A range specifying the minimum and maximum size of the attribute.

  • :in - A synonym(or alias) for :within.

  • :allow_nil - Attribute may be nil; skip validation.

  • :allow_blank - Attribute may be blank; skip validation.

  • :too_long - The error message if the attribute goes over the maximum (default is: “is too long (maximum is %count characters)”).

  • :too_short - The error message if the attribute goes under the minimum (default is: “is too short (min is %count characters)”).

  • :wrong_length - The error message if using the :is method and the attribute is the wrong size (default is: “is the wrong length (should be %count characters)”).

  • :message - The error message to use for a :minimum, :maximum, or :is violation. An alias of the appropriate too_long/too_short/wrong_length message.

  • :on - Specifies when this validation is active. Runs in all validation contexts by default (nil), other options are :create and :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.

  • :tokenizer - Specifies how to split up the attribute string. (e.g. :tokenizer => lambda {|str| str.scan(/\w+/)} to count words as in above example.) Defaults to lambda{ |value| value.split(//) } which counts individual characters.



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# File 'lib/active_model/validations/length.rb', line 99

def validates_length_of(*attr_names)
  validates_with LengthValidator, _merge_attributes(attr_names)
end

#validates_numericality_of(*attr_names) ⇒ Object

Validates whether the value of the specified attribute is numeric by trying to convert it to a float with Kernel.Float (if only_integer is false) or applying it to the regular expression /\A[+\-]?\d+\Z/ (if only_integer is set to true).

class Person < ActiveRecord::Base
  validates_numericality_of :value, :on => :create
end

Configuration options:

  • :message - A custom error message (default is: “is not a number”).

  • :on - Specifies when this validation is active. Runs in all validation contexts by default (nil), other options are :create and :update.

  • :only_integer - Specifies whether the value has to be an integer, e.g. an integral value (default is false).

  • :allow_nil - Skip validation if attribute is nil (default is false). Notice that for fixnum and float columns empty strings are converted to nil.

  • :greater_than - Specifies the value must be greater than the supplied value.

  • :greater_than_or_equal_to - Specifies the value must be greater than or equal the supplied value.

  • :equal_to - Specifies the value must be equal to the supplied value.

  • :less_than - Specifies the value must be less than the supplied value.

  • :less_than_or_equal_to - Specifies the value must be less than or equal the supplied value.

  • :odd - Specifies the value must be an odd number.

  • :even - Specifies the value must be an even number.

  • :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.

The following checks can also be supplied with a proc or a symbol which corresponds to a method:

  • :greater_than

  • :greater_than_or_equal_to

  • :equal_to

  • :less_than

  • :less_than_or_equal_to

    class Person < ActiveRecord::Base

    validates_numericality_of :width, :less_than => Proc.new { |person| person.height }
validates_numericality_of :width, :greater_than => :minimum_weight

    end



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# File 'lib/active_model/validations/numericality.rb', line 123

def validates_numericality_of(*attr_names)
  validates_with NumericalityValidator, _merge_attributes(attr_names)
end

#validates_presence_of(*attr_names) ⇒ Object

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. Runs in all validation contexts by default (nil), other options are :create and :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.



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# File 'lib/active_model/validations/presence.rb', line 39

def validates_presence_of(*attr_names)
  validates_with PresenceValidator, _merge_attributes(attr_names)
end