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Check if method is an attribute method or not.
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# File activemodel/lib/active_model/validations.rb, line 156 def attribute_method?(attribute) method_defined?(attribute) end
Copy validators on inheritance.
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# File activemodel/lib/active_model/validations.rb, line 161 def inherited(base) dup = _validators.dup base._validators = dup.each { |k, v| dup[k] = v.dup } super end
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
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# File activemodel/lib/active_model/validations.rb, line 131 def validate(*args, &block) options = args.extract_options! if options.key?(:on) options = options.dup options[:if] = Array.wrap(options[:if]) options[:if].unshift("validation_context == :#{options[:on]}") end args << options set_callback(:validate, *args, &block) end
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 :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/, :on => :create } validates :age, :inclusion => { :in => 0..9 } validates :first_name, :length => { :maximum => 30 } validates :age, :numericality => true validates :username, :presence => true validates :username, :uniqueness => true
The power of the validates
method comes when using custom
validators and default validators in one call for a given attribute e.g.
class EmailValidator < ActiveModel::EachValidator def validate_each(record, attribute, value) record.errors.add attribute, (options[:message] || "is not an email") unless value =~ /\A([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})\z/ end end class Person include ActiveModel::Validations attr_accessor :name, :email validates :name, :presence => true, :uniqueness => true, :length => { :maximum => 100 } validates :email, :presence => true, :email => true end
Validator classes may also exist within the class being validated allowing custom modules of validators to be included as needed e.g.
class Film include ActiveModel::Validations class TitleValidator < ActiveModel::EachValidator def validate_each(record, attribute, value) record.errors.add attribute, "must start with 'the'" unless value =~ /\Athe/ 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, e.g.
validates :email, :format => /@/ validates :gender, :inclusion => %W(male female) validates :password, :length => 6..20
When using shortcut form, ranges and arrays are passed to your validator’s initializer as +options+ while other types including regular expressions and strings are passed as +options+
Finally, the options :if
, :unless
,
:on
, :allow_blank
and :allow_nil
can
be given to one specific validator, as a hash:
validates :password, :presence => { :if => :password_required? }, :confirmation => true
Or to all at the same time:
validates :password, :presence => true, :confirmation => true, :if => :password_required?
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# File activemodel/lib/active_model/validations/validates.rb, line 82 def validates(*attributes) defaults = attributes.extract_options! 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.merge!(:attributes => attributes) validations.each do |key, options| key = "#{key.to_s.camelize}Validator" begin validator = key.include?('::') ? key.constantize : const_get(key) rescue NameError raise ArgumentError, "Unknown validator: '#{key}'" end validates_with(validator, defaults.merge(_parse_validates_options(options))) end end
Validates each attribute against a block.
class Person include ActiveModel::Validations attr_accessor :first_name, :last_name validates_each :first_name, :last_name do |record, attr, value| record.errors.add attr, 'starts with z.' if value.to_s[0] == zz end end
Options:
-
:on
- Specifies the context where this validation is active (e.g.:on => :create
or:on => :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
, 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 activemodel/lib/active_model/validations.rb, line 86 def validates_each(*attr_names, &block) options = attr_names.extract_options!.symbolize_keys validates_with BlockValidator, options.merge(:attributes => attr_names.flatten), &block end
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
Configuration options:
-
:on
- Specifies when this validation is active (:create
or: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.
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) options[:my_custom_key] # => "my custom value" end end
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# File activemodel/lib/active_model/validations/with.rb, line 79 def validates_with(*args, &block) options = args.extract_options! args.each do |klass| validator = klass.new(options, &block) validator.setup(self) if validator.respond_to?(:setup) 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, options) end end
List all validators that are being used to validate the model using
validates_with
method.
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# File activemodel/lib/active_model/validations.rb, line 144 def validators _validators.values.flatten.uniq end
List all validators that being used to validate a specific attribute.
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# File activemodel/lib/active_model/validations.rb, line 149 def validators_on(*attributes) attributes.map do |attribute| _validators[attribute.to_sym] end.flatten end
When creating custom validators, it might be useful to be able to specify additional default keys. This can be done by overwriting this method.
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# File activemodel/lib/active_model/validations/validates.rb, line 108 def _validates_default_keys [ :if, :unless, :on, :allow_blank, :allow_nil ] end