How to access params in the callback of a Rails model?

activemodel, activerecord, ruby-on-rails, ruby-on-rails-3, ruby-on-rails-3.2

Solution

params are not accessible in models, even if you pass them as a parameter then it would be consider as bad practice and might also be dangerous.

What you can do is to create virtual attribute and use it in your model.

class User < ActiveRecord::Base
 attr_accessible :name, :sign_up_date
 has_many :enrollments

 after_create :create_enrollment_log
 private
 def create_enrollment_log
   enrollments.create!(status: 'signed up', started: sign_up_date)
 end
end

Where sign_up_date is your virtual attribute

Problem

I have a callback of a model that needs to create a dependent object based on another field entered in the form. But `params` is undefined in the callback method. Is there another way to access it? What's the proper way to pass a callback method parameters from a form? ``` class User < ActiveRecord::Base attr_accessible :name has_many :enrollments after_create :create_enrollment_log private def create_enrollment_log enrollments.create!(status: 'signed up', started: params[:sign_up_date]) end end ```

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