Validation
If you set the virtual attribute using attr_accessor
, you should be able to validate on the model you're sending data to (alternatively using inverse_of
if you'd like to validate on the nested model):
http://api.rubyonrails.org/classes/ActiveModel/Validator.html
This can now be used in combination with the validates method (see ActiveModel::Validations::ClassMethods.validates for more on this).
class Person
include ActiveModel::Validations
attr_accessor :title
validates :title, presence: true
end
Code
I'd do this:
class Source < ActiveRecord::Base
belongs_to :source_type, inverse_of: :sources
attr_accessor :url
end
class SourceType < ActiveRecord::Base
has_many :sources, inverse_of: :source_type
validates :source_type_attr, presence: { if: :url_match? }
def url_match?
self.sources.url == [your_regex]
end
end