Class: ActiveModel::Validator
- Inherits:
-
Object
- Object
- ActiveModel::Validator
- Defined in:
- lib/active_model/validator.rb
Overview
Active Model Validator
A simple base class that can be used along with ActiveModel::Validations::ClassMethods.validates_with
class Person
include ActiveModel::Validations
validates_with MyValidator
end
class MyValidator < ActiveModel::Validator
def validate(record)
if some_complex_logic
record.errors[:base] = "This record is invalid"
end
end
private
def some_complex_logic
# ...
end
end
Any class that inherits from ActiveModel::Validator must implement a method called validate
which accepts a record
.
class Person
include ActiveModel::Validations
validates_with MyValidator
end
class MyValidator < ActiveModel::Validator
def validate(record)
record # => The person instance being validated
# => Any non-standard options passed to validates_with
end
end
To cause a validation error, you must add to the record
‘s errors directly from within the validators message
class MyValidator < ActiveModel::Validator
def validate(record)
record.errors[:base] << "This is some custom error message"
record.errors[:first_name] << "This is some complex validation"
# etc...
end
end
To add behavior to the initialize method, use the following signature:
class MyValidator < ActiveModel::Validator
def initialize(record, )
super
@my_custom_field = [:field_name] || :first_name
end
end
The easiest way to add custom validators for validating individual attributes is with the convenient ActiveModel::EachValidator for example:
class TitleValidator < ActiveModel::EachValidator
def validate_each(record, attribute, value)
record.errors[attribute] << 'must be Mr. Mrs. or Dr.' unless ['Mr.', 'Mrs.', 'Dr.'].include?(value)
end
end
This can now be used in combination with the validates
method (see ActiveModel::Validations::ClassMethods.validates for more on this)
class Person
include ActiveModel::Validations
attr_accessor :title
validates :title, :presence => true, :title => true
end
Validator may also define a setup
instance method which will get called with the class that using that validator as it’s argument. This can be useful when there are prerequisites such as an attr_accessor being present for example:
class MyValidator < ActiveModel::Validator
def setup(klass)
klass.send :attr_accessor, :custom_attribute
end
end
This setup method is only called when used with validation macros or the class level validates_with
method.
Direct Known Subclasses
Instance Attribute Summary collapse
-
#options ⇒ Object
readonly
Returns the value of attribute options.
Class Method Summary collapse
-
.kind ⇒ Object
Returns the kind of the validator.
Instance Method Summary collapse
-
#initialize(options) ⇒ Validator
constructor
Accepts options that will be made available through the
options
reader. -
#kind ⇒ Object
Return the kind for this validator.
-
#validate(record) ⇒ Object
Override this method in subclasses with validation logic, adding errors to the records
errors
array where necessary.
Constructor Details
#initialize(options) ⇒ Validator
Accepts options that will be made available through the options
reader.
113 114 115 |
# File 'lib/active_model/validator.rb', line 113 def initialize() @options = .freeze end |
Instance Attribute Details
#options ⇒ Object (readonly)
Returns the value of attribute options.
99 100 101 |
# File 'lib/active_model/validator.rb', line 99 def @options end |
Class Method Details
.kind ⇒ Object
Returns the kind of the validator.
Examples
PresenceValidator.kind # => :presence
UniquenessValidator.kind # => :uniqueness
108 109 110 |
# File 'lib/active_model/validator.rb', line 108 def self.kind @kind ||= name.split('::').last.underscore.sub(/_validator$/, '').to_sym unless anonymous? end |
Instance Method Details
#kind ⇒ Object
Return the kind for this validator.
118 119 120 |
# File 'lib/active_model/validator.rb', line 118 def kind self.class.kind end |
#validate(record) ⇒ Object
Override this method in subclasses with validation logic, adding errors to the records errors
array where necessary.
124 125 126 |
# File 'lib/active_model/validator.rb', line 124 def validate(record) raise NotImplementedError end |