Module: ActiveModel::Validations::ClassMethods
Relationships & Source Files | |
Defined in: | activemodel/lib/active_model/validations.rb, activemodel/lib/active_model/validations/validates.rb, activemodel/lib/active_model/validations/with.rb |
Instance Method Summary
-
#attribute_method?(attribute) ⇒ Boolean
Returns
true
ifattribute
is an attribute method,false
otherwise. -
#clear_validators!
Clears all of the validators and validations.
-
#validate(*args, &block)
Adds a validation method or block to the class.
-
#validates(*attributes)
This method is a shortcut to all default validators and any custom validator classes ending in ‘Validator’.
-
#validates!(*attributes)
This method is used to define validations that cannot be corrected by end users and are considered exceptional.
-
#validates_each(*attr_names, &block)
Validates each attribute against a block.
-
#validates_with(*args, &block)
Passes the record off to the class or classes specified and allows them to add errors based on more complex conditions.
-
#validators
List all validators that are being used to validate the model using #validates_with method.
-
#validators_on(*attributes)
List all validators that are being used to validate a specific attribute.
Instance Method Details
#attribute_method?(attribute) ⇒ Boolean
Returns true
if attribute
is an attribute method, false
otherwise.
class Person
include ActiveModel::Validations
attr_accessor :name
end
User.attribute_method?(:name) # => true
User.attribute_method?(:age) # => false
# File 'activemodel/lib/active_model/validations.rb', line 284
def attribute_method?(attribute) method_defined?(attribute) end
#clear_validators!
Clears all of the validators and validations.
Note that this will clear anything that is being used to validate the model for both the #validates_with and #validate methods. It clears the validators that are created with an invocation of #validates_with and the callbacks that are set by an invocation of #validate.
class Person
include ActiveModel::Validations
validates_with MyValidator
validates_with OtherValidator, on: :create
validates_with StrictValidator, strict: true
validate :cannot_be_robot
def cannot_be_robot
errors.add(:base, 'A person cannot be a robot') if person_is_robot
end
end
Person.validators
# => [
# #<MyValidator:0x007fbff403e808 @options={}>,
# #<OtherValidator:0x007fbff403d930 @options={on: :create}>,
# #<StrictValidator:0x007fbff3204a30 @options={strict:true}>
# ]
If one runs Person.clear_validators!
and then checks to see what validators this class has, you would obtain:
Person.validators # => []
Also, the callback set by validate :cannot_be_robot
will be erased so that:
Person._validate_callbacks.empty? # => true
# File 'activemodel/lib/active_model/validations.rb', line 248
def clear_validators! reset_callbacks(:validate) _validators.clear end
#validate(*args, &block)
Adds a validation method or block to the class. This is useful when overriding the validate
instance method becomes too unwieldy and you’re looking for more descriptive declaration of your validations.
This can be done with a symbol pointing to a method:
class Comment
include ActiveModel::Validations
validate :must_be_friends
def must_be_friends
errors.add(:base, 'Must be friends to leave a comment') unless commenter.friend_of?(commentee)
end
end
With a block which is passed with the current record to be validated:
class Comment
include ActiveModel::Validations
validate do |comment|
comment.must_be_friends
end
def must_be_friends
errors.add(:base, 'Must be friends to leave a comment') unless commenter.friend_of?(commentee)
end
end
Or with a block where self
points to the current record to be validated:
class Comment
include ActiveModel::Validations
validate do
errors.add(:base, 'Must be friends to leave a comment') unless commenter.friend_of?(commentee)
end
end
Note that the return value of validation methods is not relevant. It’s not possible to halt the validate callback chain.
Options:
-
:on
- Specifies the contexts where this validation is active. Runs in all validation contexts by defaultnil
. You can pass a symbol or an array of symbols. (e.g.on: :create
oron: :custom_validation_context
oron: [:create, :custom_validation_context]
) -
:if
- Specifies a method, proc, or string to call to determine if the validation should occur (e.g.if: :allow_validation
, orif: Proc.new { |user| user.signup_step > 2 }
). The method, proc or string should return or evaluate to atrue
orfalse
value. -
:unless
- Specifies a method, proc, or string to call to determine if the validation should not occur (e.g.unless: :skip_validation
, orunless: Proc.new { |user| user.signup_step <= 2 }
). The method, proc, or string should return or evaluate to atrue
orfalse
value.
NOTE: Calling validate
multiple times on the same method will overwrite previous definitions.
# File 'activemodel/lib/active_model/validations.rb', line 171
def validate(*args, &block) = args. if args.all?(Symbol) .each_key do |k| unless VALID_OPTIONS_FOR_VALIDATE.include?(k) raise ArgumentError.new("Unknown key: #{k.inspect}. Valid keys are: #{VALID_OPTIONS_FOR_VALIDATE.map(&:inspect).join(', ')}. Perhaps you meant to call `validates` instead of `validate`?") end end end if .key?(:on) = .merge(if: [predicate_for_validation_context( [:on]), * [:if]]) end set_callback(:validate, *args, , &block) end
#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 :username, absence: true
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
The power of the validates
method comes when using custom validators and default validators in one call for a given attribute.
class EmailValidator < ActiveModel::EachValidator
def validate_each(record, attribute, value)
record.errors.add attribute, ( [: ] || "is not an email") unless
/\A([^@\s])@((?:[-a-z0-9]\.)+[a-z]{2,})\z/i.match?(value)
end
end
class Person
include ActiveModel::Validations
attr_accessor :name, :email
validates :name, presence: true, length: { maximum: 100 }
validates :email, presence: true, email: true
end
::ActiveModel::Validator
classes may also exist within the class being validated allowing custom modules of validators to be included as needed.
class Film
include ActiveModel::Validations
class TitleValidator < ActiveModel::EachValidator
def validate_each(record, attribute, value)
record.errors.add attribute, "must start with 'the'" unless /\Athe/i.match?(value)
end
end
validates :name, title: true
end
Additionally validator classes may be in another namespace and still used within any class.
validates :name, :'film/title' => true
The validators hash can also handle regular expressions, ranges, arrays and strings in shortcut form.
validates :email, format: /@/
validates :role, inclusion: %w(admin contributor)
validates :password, length: 6..20
When using shortcut form, ranges and arrays are passed to your validator’s initializer as options[:in]
while other types including regular expressions and strings are passed as options[:with]
.
There is also a list of options that could be used along with validators:
-
:on
- Specifies the contexts where this validation is active. Runs in all validation contexts by defaultnil
. You can pass a symbol or an array of symbols. (e.g.on: :create
oron: :custom_validation_context
oron: [:create, :custom_validation_context]
) -
:if
- Specifies a method, proc, or string to call to determine if the validation should occur (e.g.if: :allow_validation
, orif: Proc.new { |user| user.signup_step > 2 }
). The method, proc or string should return or evaluate to atrue
orfalse
value. -
:unless
- Specifies a method, proc, or string to call to determine if the validation should not occur (e.g.unless: :skip_validation
, orunless: Proc.new { |user| user.signup_step <= 2 }
). The method, proc, or string should return or evaluate to atrue
orfalse
value. -
:allow_nil
- Skip validation if the attribute isnil
. -
:allow_blank
- Skip validation if the attribute is blank. -
:strict
- If the:strict
option is set to true will raise ActiveModel::StrictValidationFailed instead of adding the error.:strict
option can also be set to any other exception.
Example:
validates :password, presence: true, confirmation: true, if: :password_required?
validates :token, length: { is: 24 }, strict: TokenLengthException
Finally, the options :if
, :unless
, :on
, :allow_blank
, :allow_nil
, :strict
and :message
can be given to one specific validator, as a hash:
validates :password, presence: { if: :password_required?, message: 'is forgotten.' }, confirmation: true
# File 'activemodel/lib/active_model/validations/validates.rb', line 106
def validates(*attributes) defaults = attributes. .dup validations = defaults.slice!(*_validates_default_keys) raise ArgumentError, "You need to supply at least one attribute" if attributes.empty? raise ArgumentError, "You need to supply at least one validation" if validations.empty? defaults[:attributes] = attributes validations.each do |key, | key = "#{key.to_s.camelize}Validator" begin validator = const_get(key) rescue NameError raise ArgumentError, "Unknown validator: '#{key}'" end next unless validates_with(validator, defaults.merge( ( ))) end end
#validates!(*attributes)
This method is used to define validations that cannot be corrected by end users and are considered exceptional. So each validator defined with bang or :strict
option set to true
will always raise ::ActiveModel::StrictValidationFailed
instead of adding error when validation fails. See #validates for more information about the validation itself.
class Person
include ActiveModel::Validations
attr_accessor :name
validates! :name, presence: true
end
person = Person.new
person.name = ''
person.valid?
# => ActiveModel::StrictValidationFailed: Name can't be blank
# File 'activemodel/lib/active_model/validations/validates.rb', line 148
def validates!(*attributes) = attributes. [:strict] = true validates(*(attributes << )) end
#validates_each(*attr_names, &block)
Validates each attribute against a block.
class Person
include ActiveModel::Validations
attr_accessor :first_name, :last_name
validates_each :first_name, :last_name, allow_blank: true do |record, attr, value|
record.errors.add attr, "starts with z." if value.start_with?("z")
end
end
Options:
-
:on
- Specifies the contexts where this validation is active. Runs in all validation contexts by defaultnil
. You can pass a symbol or an array of symbols. (e.g.on: :create
oron: :custom_validation_context
oron: [:create, :custom_validation_context]
) -
:allow_nil
- Skip validation if attribute isnil
. -
:allow_blank
- Skip validation if attribute is blank. -
:if
- Specifies a method, proc, or string to call to determine if the validation should occur (e.g.if: :allow_validation
, orif: Proc.new { |user| user.signup_step > 2 }
). The method, proc or string should return or evaluate to atrue
orfalse
value. -
:unless
- Specifies a method, proc, or string to call to determine if the validation should not occur (e.g.unless: :skip_validation
, orunless: Proc.new { |user| user.signup_step <= 2 }
). The method, proc, or string should return or evaluate to atrue
orfalse
value.
# File 'activemodel/lib/active_model/validations.rb', line 104
def validates_each(*attr_names, &block) validates_with BlockValidator, _merge_attributes(attr_names), &block end
#validates_with(*args, &block)
Passes the record off to the class or classes specified and allows them to add errors based on more complex conditions.
class Person
include ActiveModel::Validations
validates_with MyValidator
end
class MyValidator < ActiveModel::Validator
def validate(record)
if some_complex_logic
record.errors.add :base, 'This record is invalid'
end
end
private
def some_complex_logic
# ...
end
end
You may also pass it multiple classes, like so:
class Person
include ActiveModel::Validations
validates_with MyValidator, MyOtherValidator, on: :create
end
There is no default error message for validates_with
. You must manually add errors to the record’s errors collection in the validator class.
To implement the validate method, you must have a record
parameter defined, which is the record to be validated.
Configuration options:
-
:on
- Specifies the contexts where this validation is active. Runs in all validation contexts by defaultnil
. You can pass a symbol or an array of symbols. (e.g.on: :create
oron: :custom_validation_context
oron: [:create, :custom_validation_context]
) -
:if
- Specifies a method, proc, or string to call to determine if the validation should occur (e.g.if: :allow_validation
, orif: Proc.new { |user| user.signup_step > 2 }
). The method, proc, or string should return or evaluate to atrue
orfalse
value. -
:unless
- Specifies a method, proc, or string to call to determine if the validation should not occur (e.g.unless: :skip_validation
, orunless: Proc.new { |user| user.signup_step <= 2 }
). The method, proc, or string should return or evaluate to atrue
orfalse
value. -
:strict
- Specifies whether validation should be strict. SeeActiveModel::Validations#validates!
for more information.
If you pass any additional configuration options, they will be passed to the class and available as options
:
class Person
include ActiveModel::Validations
validates_with MyValidator, my_custom_key: 'my custom value'
end
class MyValidator < ActiveModel::Validator
def validate(record)
[:my_custom_key] # => "my custom value"
end
end
# File 'activemodel/lib/active_model/validations/with.rb', line 88
def validates_with(*args, &block) = args. [:class] = self args.each do |klass| validator = klass.new( .dup, &block) if validator.respond_to?(:attributes) && !validator.attributes.empty? validator.attributes.each do |attribute| _validators[attribute.to_sym] << validator end else _validators[nil] << validator end validate(validator, ) end end
#validators
List all validators that are being used to validate the model using #validates_with method.
class Person
include ActiveModel::Validations
validates_with MyValidator
validates_with OtherValidator, on: :create
validates_with StrictValidator, strict: true
end
Person.validators
# => [
# #<MyValidator:0x007fbff403e808 @options={}>,
# #<OtherValidator:0x007fbff403d930 @options={on: :create}>,
# #<StrictValidator:0x007fbff3204a30 @options={strict:true}>
# ]
# File 'activemodel/lib/active_model/validations.rb', line 206
def validators _validators.values.flatten.uniq end
#validators_on(*attributes)
List all validators that are being used to validate a specific attribute.
class Person
include ActiveModel::Validations
attr_accessor :name, :age
validates_presence_of :name
validates_inclusion_of :age, in: 0..99
end
Person.validators_on(:name)
# => [
# #<ActiveModel::Validations::PresenceValidator:0x007fe604914e60 @attributes=[:name], @options={}>,
# ]
# File 'activemodel/lib/active_model/validations.rb', line 268
def validators_on(*attributes) attributes.flat_map do |attribute| _validators[attribute.to_sym] end end