Ruby on Rails - Activeadmin - Update model with virtual attribute

Question

I have a activeadmin form to which allows to add a youtube URL. I validate this URL in my video model. It does works well when I want to add a new video but does nothing when I'm editing the video.
app/admin/video.rb :

ActiveAdmin.register Media, as: 'Videos' do     
form do |f|
        f.inputs "Add youtube video" do
          f.input :category
          f.semantic_errors :error
            f.has_many :videos, allow_destroy: true do |g|
                g.input :mylink, :label => "Youtube link : ",  :type => :text
        end
        actions
        end
     end
end

model/video.rb :

class Video < ApplicationRecord
  belongs_to :media
  attr_accessor :mylink 
  YT_LINK_FORMAT = /\A.*(youtu.be\/|v\/|u\/\w\/|embed\/|watch\?v=|\&v=)([^#\&\?]*).*\z/i
  before_create :before_add_to_galerie
  before_update :before_add_to_galerie

  def before_add_to_galerie
    uid = @mylink.match(YT_LINK_FORMAT)
    self.uid = uid[2] if uid && uid[2]
    if self.uid.to_s.length != 11
      self.errors.add(:mylink, 'is invalid.')
      throw :abort
      false
    elsif Video.where(uid: self.uid).any?
      self.errors.add(:mylink, 'is not unique.')
      throw :abort
      false
    end
end

validates :mylink, presence: true, format: YT_LINK_FORMAT
end

It looks like the before_update method is never triggered.
How can I make my edit work ?

EDIT :I figured out that it is calling the before_update link for the Media model and not for the Video one.But the create is fine.

why do you think it's not triggered? Have you tried to update an existing record? — Bohdan, Apr 17 '17 at 16:26
I just tried to call another method in the before_update that only print some text into the console and it does not print anything — KingOfBabu, Apr 17 '17 at 16:35
It does work when I don't use the virtual attribute but I really need this to validate the link — KingOfBabu, Apr 17 '17 at 17:13

Bohdan · Accepted Answer · 2017-04-18T18:37:47.450

Let me try to rephrase the issue:

You have a model Video
Video has a virtual attribute my_link
Video has a before_update callback before_add_to_galerie
You want this callback to trigger when only my_link was changed

does this look correct? If so you have 2 options, first - if you have updated_at change it along with my_link

class Video < ApplicationRecord
  attr_reader :my_link
  # ...
  def my_link=(val)
    return val if val == my_link
    @my_link = val
    self.updated_at = Time.zone.now
  end
end

or you can use ActiveModel

Ruby on Rails - Activeadmin - Update model with virtual attribute

1 Answers1