Question

I am using Ruby on Rails 3 and I would like to retrieve validating field names. That is, I defined some validation for a class and I would like to retrieve what fields (their names) are candidate for validation on submitting a form.

I need that because I would like to “play” with class error attributes (<name_class>.errors).

How can I do?

Answer 1

You can access your model’s validators method. This will return an array of validators on your model.

For example, if you had this:

class User < ActiveRecord::Base
  validates :name, :presence => true
  validates :email, :uniqueness => true
end

Then you could access the validators like this:

User.validators
# => [#<ActiveModel::Validations::PresenceValidator:0x123456 @attributes=[:name], @options={}>....]
User.validators.first.attributes
# => [:name]
User.validators.first.class
# => ActiveModel::Validations::PresenceValidator