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module ActiveModel #:nodoc:
# A simple base class that can be used along with ActiveModel::Base.validates_with
#
# class Person < ActiveModel::Base
# validates_with MyValidator
# end
#
# class MyValidator < ActiveModel::Validator
# def validate
# 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 will have access to <tt>record</tt>,
# which is an instance of the record being validated, and must implement a method called <tt>validate</tt>.
#
# class Person < ActiveModel::Base
# validates_with MyValidator
# end
#
# class MyValidator < ActiveModel::Validator
# def validate
# record # => The person instance being validated
# options # => Any non-standard options passed to validates_with
# end
# end
#
# To cause a validation error, you must add to the <tt>record<tt>'s errors directly
# from within the validators message
#
# class MyValidator < ActiveModel::Validator
# def validate
# 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, options)
# super
# @my_custom_field = options[:field_name] || :first_name
# end
# end
class Validator
attr_reader :options
def initialize(options)
@options = options
end
def validate(record)
raise NotImplementedError
end
end
# EachValidator is a validator which iterates through the attributes given
# in the options hash invoking the validate_each method passing in the
# record, attribute and value.
#
# All ActiveModel validations are built on top of this Validator.
class EachValidator < Validator
attr_reader :attributes
def initialize(options)
@attributes = Array(options.delete(:attributes))
raise ":attributes cannot be blank" if @attributes.empty?
super
check_validity!
end
def validate(record)
attributes.each do |attribute|
value = record.send(:read_attribute_for_validation, attribute)
next if (value.nil? && options[:allow_nil]) || (value.blank? && options[:allow_blank])
validate_each(record, attribute, value)
end
end
def validate_each(record, attribute, value)
raise NotImplementedError
end
def check_validity!
end
end
# BlockValidator is a special EachValidator which receives a block on initialization
# and call this block for each attribute being validated. +validates_each+ uses this
# Validator.
class BlockValidator < EachValidator
def initialize(options, &block)
@block = block
super
end
def validate_each(record, attribute, value)
@block.call(record, attribute, value)
end
end
end
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