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module ActiveModel
module Validations
class AcceptanceValidator < EachValidator # :nodoc:
def initialize(options)
super({ allow_nil: true, accept: ["1", true] }.merge!(options))
setup!(options[:class])
end
def validate_each(record, attribute, value)
unless acceptable_option?(value)
record.errors.add(attribute, :accepted, options.except(:accept, :allow_nil))
end
end
private
def setup!(klass)
klass.include(LazilyDefineAttributes.new(AttributeDefinition.new(attributes)))
end
def acceptable_option?(value)
Array(options[:accept]).include?(value)
end
class LazilyDefineAttributes < Module
def initialize(attribute_definition)
define_method(:respond_to_missing?) do |method_name, include_private=false|
super(method_name, include_private) || attribute_definition.matches?(method_name)
end
define_method(:method_missing) do |method_name, *args, &block|
if attribute_definition.matches?(method_name)
attribute_definition.define_on(self.class)
send(method_name, *args, &block)
else
super(method_name, *args, &block)
end
end
end
end
class AttributeDefinition
def initialize(attributes)
@attributes = attributes.map(&:to_s)
end
def matches?(method_name)
attr_name = convert_to_reader_name(method_name)
attributes.include?(attr_name)
end
def define_on(klass)
attr_readers = attributes.reject { |name| klass.attribute_method?(name) }
attr_writers = attributes.reject { |name| klass.attribute_method?("#{name}=") }
klass.send(:attr_reader, *attr_readers)
klass.send(:attr_writer, *attr_writers)
end
protected
attr_reader :attributes
private
def convert_to_reader_name(method_name)
method_name.to_s.chomp("=")
end
end
end
module HelperMethods
# 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:
# * <tt>:message</tt> - A custom error message (default is: "must be
# accepted").
# * <tt>:accept</tt> - 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" to +true+
# before validation.
#
# There is also a list of default options supported by every validator:
# +:if+, +:unless+, +:on+, +:allow_nil+, +:allow_blank+, and +:strict+.
# See <tt>ActiveModel::Validation#validates</tt> for more information.
def validates_acceptance_of(*attr_names)
validates_with AcceptanceValidator, _merge_attributes(attr_names)
end
end
end
end
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