I’m writing a library that will require programmatically copying
validations from one model to another, but I’m stumped on how to pull
this
off.
I have a model that is an ActiveModel::Model with some validation:
class User < ActiveRecord::Base
validates :name, presence: true
end
And another model that I’d like to have the same validations:
class UserForm
include ActiveModel::Model
attr_accessor :name
end
Now I’d like to give UserForm the same validations as User, and
without
modifying User. Copying the validators over doesn’t work, because
ActiveModel::Validations hooks into callbacks during the validation
check:
UserForm._validators = User._validators
UserForm.new.valid?
# => true # We wanted to see `false` here, but no
validations
# are actually running because the :validate
callback
# is empty.
Unfortunately, there doesn’t seem to be an easy way that I can see to
programmatically give one model another’s validation callbacks and still
have it work. I think my best bet is if I can ask Rails to regenerate
the
validation callbacks based on the validators that are present at a given
moment in time.
Is that possible? If not, is there a better way to do this?