Skipping :touch associations when saving an ActiveRecord object

activerecord, ruby, ruby-on-rails

Solution

One option that avoids directly monkey patching is to override the method that gets created when you have a relation with a `:touch` attribute.

Given the setup from the OP:

class Student < ActiveRecord::Base
  belongs_to :school, touch: true

  attr_accessor :skip_touch

  def belongs_to_touch_after_save_or_destroy_for_school
    super unless skip_touch
  end

  after_commit :reset_skip_touch

  def reset_skip_touch
    skip_touch = false
  end
end

@student.skip_touch = true
@student.save # touch will be skipped for this save

This is obviously pretty hacky and depends on really specific internal implementation details in AR.

Problem

Is there a way to skip updating associations with a `:touch` association when saving? Setup: ``` class School < ActiveRecord::Base has_many :students end class Student < ActiveRecord::Base belongs_to :school, touch: true end ``` I would like to be able to do something like the following where the touch is skipped. ``` @school = School.create @student = Student.create(school_id: @school.id) @student.name = "Trevor" @student.save # Can I do this without touching the @school record? ``` Can you do this? Something like `@student.save(skip_touch: true)` would be fantastic but I haven't found anything like that. I don't want to use something like `update_column` because I don't want to skip the AR callbacks.

Original source