instance method
attr_readonly
Ruby on Rails edge
Since v3.2.22.5Signature
attr_readonly(*attributes)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
Parameters
-
attributesrest
Source
# File activerecord/lib/active_record/readonly_attributes.rb, line 32
def attr_readonly(*attributes)
attributes = attributes.map(&:to_s)
self._attr_readonly = ActiveSupport::Ractors.make_shareable(_attr_readonly | attributes)
# Pass the new attributes down to subclasses that hold their own copy.
descendants.each do |subclass|
next if subclass._attr_readonly.equal?(subclass.superclass._attr_readonly)
subclass._attr_readonly = ActiveSupport::Ractors.make_shareable(subclass._attr_readonly | attributes)
end
if ActiveRecord._raise_on_assign_to_attr_readonly
# The code generator changed, also for subclasses that already
# generated their own writers.
undefine_attribute_methods
descendants.each(&:undefine_attribute_methods)
include(HasReadonlyAttributes)
end
end
Defined in activerecord/lib/active_record/readonly_attributes.rb line 32
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