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:
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]
end
end
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:
person = Person.new person.validate! # => ["cannot be nil"] person.errors.full_messages # => ["name cannot be nil"] # etc..