ri > ActiveModel::Validations

= ActiveModel::Validations

------------------------------------------------------------------------
= Includes:
HelperMethods (from /home/chedong/.local/share/rdoc)

------------------------------------------------------------------------
= Extended by:
(from /home/chedong/.local/share/rdoc)
  ActiveSupport::Concern
  ActiveModel::Naming
  ActiveModel::Callbacks
  ActiveModel::Translation
  HelperMethods

(from /home/chedong/.local/share/rdoc)
------------------------------------------------------------------------
== Active Model Validations

Provides a full validation framework to your objects.

A minimal implementation could be:

  class Person
    include ActiveModel::Validations

    attr_accessor :first_name, :last_name

    validates_each :first_name, :last_name do |record, attr, value|
      record.errors.add attr, "starts with z." if value.start_with?("z")
    end
  end

Which provides you with the full standard validation stack that you know
from Active Record:

  person = Person.new
  person.valid?                   # => true
  person.invalid?                 # => false

  person.first_name = 'zoolander'
  person.valid?                   # => false
  person.invalid?                 # => true
  person.errors.messages          # => {first_name:["starts with z."]}

Note that ActiveModel::Validations automatically adds an errors method
to your instances initialized with a new ActiveModel::Errors object, so
there is no need for you to do this manually.














------------------------------------------------------------------------
= Instance methods:

  errors
  invalid?
  raise_validation_error
  valid?
  validate
  validate!
  validates_with
  validation_context

= Attributes:

  attr_accessor validation_context