- V
Instance Public methods
validates_absence_of(*attr_names) Link
Validates that the specified attributes are blank (as defined by Object#present?
). Happens by default on save.
class Person < ActiveRecord::Base
validates_absence_of :first_name
end
The first_name attribute must be in the object and it must be blank.
Configuration options:
-
:message
- A custom error message (default is: “must be blank”).
There is also a list of default options supported by every validator: :if
, :unless
, :on
, :allow_nil
, :allow_blank
, and :strict
. See ActiveModel::Validations#validates
for more information
validates_acceptance_of(*attr_names) Link
Encapsulates the pattern of wanting to validate the acceptance of a terms of service check box (or similar agreement).
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”). -
:accept
- Specifies a value that is considered accepted. Also accepts an array of possible values. The default value is an array [“1”, true], which makes it easy to relate to an HTML checkbox. This should be set to, or include,true
if you are validating a database column, since the attribute is typecast from “1” totrue
before validation.
There is also a list of default options supported by every validator: :if
, :unless
, :on
, :allow_nil
, :allow_blank
, and :strict
. See ActiveModel::Validations#validates
for more information.
validates_confirmation_of(*attr_names) Link
Encapsulates the pattern of wanting to validate a password or email address field with a confirmation.
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
. 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%{translated_attribute_name}
”). -
:case_sensitive
- Looks for an exact match. Ignored by non-text columns (true
by default).
There is also a list of default options supported by every validator: :if
, :unless
, :on
, :allow_nil
, :allow_blank
, and :strict
. See ActiveModel::Validations#validates
for more information
validates_exclusion_of(*attr_names) Link
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: ->(person) { [person.username, person.first_name] },
message: 'should not be the same as your username or first name'
validates_exclusion_of :karma, in: :reserved_karmas
end
Configuration options:
-
:in
- An enumerable object of items that the value shouldn't be part of. This can be supplied as a proc, lambda or symbol which returns an enumerable. If the enumerable is a numerical, time or datetime range the test is performed withRange#cover?
, otherwise withinclude?
. When using a proc or lambda the instance under validation is passed as an argument. -
:within
- A synonym(or alias) for:in
Range#cover?
, otherwise withinclude?
. -
:message
- Specifies a custom error message (default is: “is reserved”).
There is also a list of default options supported by every validator: :if
, :unless
, :on
, :allow_nil
, :allow_blank
, and :strict
. See ActiveModel::Validations#validates
for more information
validates_format_of(*attr_names) Link
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: ->(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.
Due to frequent misuse of ^
and $
, you need to pass the multiline: true
option in case you use any of these two anchors in the provided regular expression. In most cases, you should be using \A
and \z
.
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”). -
: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. -
:multiline
- Set to true if your regular expression contains anchors that match the beginning or end of lines as opposed to the beginning or end of the string. These anchors are^
and$
.
There is also a list of default options supported by every validator: :if
, :unless
, :on
, :allow_nil
, :allow_blank
, and :strict
. See ActiveModel::Validations#validates
for more information
validates_inclusion_of(*attr_names) Link
Validates whether the value of the specified attribute is available in a particular enumerable object.
class Person < ActiveRecord::Base
validates_inclusion_of :role, in: %w( admin contributor )
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: ->(person) { STATES[person.country] }
validates_inclusion_of :karma, in: :available_karmas
end
Configuration options:
-
:in
- An enumerable object of available items. This can be supplied as a proc, lambda or symbol which returns an enumerable. If the enumerable is a numerical, time or datetime range the test is performed withRange#cover?
, otherwise withinclude?
. When using a proc or lambda the instance under validation is passed as an argument. -
:within
- A synonym(or alias) for:in
-
:message
- Specifies a custom error message (default is: “is not included in the list”).
There is also a list of default options supported by every validator: :if
, :unless
, :on
, :allow_nil
, :allow_blank
, and :strict
. See ActiveModel::Validations#validates
for more information
validates_length_of(*attr_names) Link
Validates that the specified attributes match the length restrictions supplied. Only one constraint option can be used at a time apart from :minimum
and :maximum
that can be combined together:
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 :words_in_essay, minimum: 100, too_short: 'Your essay must be at least 100 words.'
private
def words_in_essay
essay.scan(/\w+/)
end
end
Constraint options:
-
:minimum
- The minimum size of the attribute. -
:maximum
- The maximum size of the attribute. Allowsnil
by default if not used with:minimum
. -
: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
.
Other options:
-
:allow_nil
- Attribute may benil
; 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 (minimum 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 appropriatetoo_long
/too_short
/wrong_length
message.
There is also a list of default options supported by every validator: :if
, :unless
, :on
and :strict
. See ActiveModel::Validations#validates
for more information
validates_numericality_of(*attr_names) Link
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
). Precision of Kernel
.Float values are guaranteed up to 15 digits.
class Person < ActiveRecord::Base
validates_numericality_of :value, on: :create
end
Configuration options:
-
:message
- A custom error message (default is: “is not a number”). -
:only_integer
- Specifies whether the value has to be an integer, e.g. an integral value (default isfalse
). -
:allow_nil
- Skip validation if attribute isnil
(default isfalse
). Notice that forInteger
andFloat
columns empty strings are converted tonil
. -
: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. -
:other_than
- Specifies the value must be other than the supplied value. -
:odd
- Specifies the value must be an odd number. -
:even
- Specifies the value must be an even number.
There is also a list of default options supported by every validator: :if
, :unless
, :on
, :allow_nil
, :allow_blank
, and :strict
. See ActiveModel::Validations#validates
for more information
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
-
:only_integer
-
:other_than
For example:
class Person < ActiveRecord::Base
validates_numericality_of :width, less_than: ->(person) { person.height }
validates_numericality_of :width, greater_than: :minimum_weight
end
validates_presence_of(*attr_names) Link
Validates that the specified attributes are not blank (as defined by Object#blank?
). Happens by default on save.
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”).
There is also a list of default options supported by every validator: :if
, :unless
, :on
, :allow_nil
, :allow_blank
, and :strict
. See ActiveModel::Validations#validates
for more information