Update a datetime attribute using a boolean input

Question

I've got a model Story for which I'm adding a pinned_at attribute. I want a user to be able to select if the story needs to be pinned to the top of the index page but not be able to set the datetime value as it should always be the present datetime when being set.

My thinking was something like

= f.check_box :pinned_at, value: DateTime.now

But the value doesn't seem to set. Anyone have any ideas? The reason why it's not a simple boolean attribute in the first place is that I want to sort stories by whether they are pinned and their creation date. I don't think rails has a good way of sorting by a boolean?

Answer 1

Just use a datetime column together with a separate setter/getter:

class Story < ApplicationRecord
  def pinned
    pinned_at.present?
  end
  alias_method :pinned?, :pinned

  def pinned=(value)
    if value
      self.pinned_at = Time.current unless pinned? 
    else
      self.pinned_at = nil
    end
  end
end

= f.check_box :pinned