Type:
Class
Constants:
CALLBACKS_OPTIONS
:
[:if, :unless, :on, :allow_nil, :allow_blank, :strict]
Active Model Errors
Provides a modified Hash that you can include in your object
for handling error messages and interacting with Action View helpers.
A minimal implementation could be:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 | class Person # Required dependency for ActiveModel::Errors extend ActiveModel::Naming def initialize @errors = ActiveModel::Errors.new(self) end attr_accessor :name attr_reader :errors def validate! errors.add(:name, "cannot be nil") if name == nil end # The following methods are needed to be minimally implemented def read_attribute_for_validation(attr) send(attr) end def Person.human_attribute_name(attr, options = {}) attr end def Person.lookup_ancestors [self] endend |
The last three methods are required in your object for Errors to be able to generate error messages correctly and also handle multiple languages. Of course, if you extend your object with ActiveModel::Translation you will not need to implement the last two. Likewise, using ActiveModel::Validations will handle the validation related methods for you.
The above allows you to do:
1 2 3 4 | person = Person.newperson.validate! # => ["cannot be nil"]person.errors.full_messages # => ["name cannot be nil"]# etc.. |