Method: ActiveRecord::ReadonlyAttributes::ClassMethods#attr_readonly

Defined in:

activerecord/lib/active_record/readonly_attributes.rb

#attr_readonly(*attributes) ⇒ Object

Attributes listed as readonly will be used to create a new record. Assigning a new value to a readonly attribute on a persisted record raises an error.

By setting config.active_record.raise_on_assign_to_attr_readonly to false, it will not raise. The value will change in memory, but will not be persisted on save.

Examples

class Post < ActiveRecord::Base
  attr_readonly :title
end

post = Post.create!(title: "Introducing Ruby on Rails!")
post.title = "a different title" # raises ActiveRecord::ReadonlyAttributeError
post.update(title: "a different title") # raises ActiveRecord::ReadonlyAttributeError

# File 'activerecord/lib/active_record/readonly_attributes.rb', line 30

def attr_readonly(*attributes)
  self._attr_readonly |= attributes.map(&:to_s)

  if ActiveRecord.raise_on_assign_to_attr_readonly
    include(HasReadonlyAttributes)
  end
end