Question

I am a Objective-c programmer so I am not used to having code outside of methods.

I have a two-part question about Rail’s validates.

Consider this code:

class User < ActiveRecord::Base
  attr_accessible :name, :email

  email_regex = /\A[\w+\-.]+@[a-z\d\-.]+\.[a-z]+\z/i

  validates :name,  :presence   => true,
                    :length     => { :maximum => 50}

  validates :email, :presence   => true,
                    :format     => { :with => email_regex }.
                    :uniqueness => true

end

1. When exactly is the validates method executed? Upon instantiating a User instance or when its class definition is loaded?
2. When does the User actually get validated? When I save the User instance or create it?

Answer 1

All of the calls within the class definition are called when the class definition is executed, not when an instance is created. It is worth mentioning that the variable email_regex is not a instance variable, but rather a local variable to the class definition.