Active Model Errors

Provides a modified OrderedHash that you can include in your object for handling error messages and interacting with Action Pack 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, "can not 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::Translations 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: 

  p = Person.new
  p.validate!             # => ["can not be nil"]
  p.errors.full_messages  # => ["name can not be nil"]
  # etc..

Aliases

  • []
  • set

Constants

CALLBACKS_OPTIONS = [:if, :unless, :on, :allow_nil, :allow_blank]

Attributes

Show files where this class is defined (1 file)
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