How to check if an attribute has a presence validation in Ruby on Rails

Question

Is there a way to know if an attribute has a validation? Something like following:

Model.attribute.has_presence_validation?

Answer 1

Well not sure about simplest solution but I achieved this functionality with quite complexity. Maybe someone come up with some simpler solution. Here is the code which worked perfectly for me.

I get all the validations on a model, chose presence validations(ActiveRecord::Validations::PresenceValidator) and then select all of their attributes and used include to check attribute(:your_attribute)presence in this array

Model.validators.collect{|validation| validation if validation.class==ActiveRecord::Validations::PresenceValidator}.compact.collect(&:attributes).flatten.include? :your_attribute

you can change compare statement

validation.class==ActiveRecord::Validations::PresenceValidator

to get all other types validation i.e uniqueness etc

Answer 2

For me, the following code is working (it is basically checking if any validator for given field is an instance of the presence validator):

MyModel.validators_on(:my_attribute).any?{|validator| validator.kind_of?(ActiveModel::Validations::PresenceValidator)}