Question

I have the following two classes:

class Menu < ActiveRecord::Base
  has_many :menu_headers
  accepts_nested_attributes_for :menu_headers
end

class MenuHeader < ActiveRecord::Base
  belongs_to :menu
end

Here’s the quetsion:
I am populating via a json file:

{"name":"Dinner Menu","internal_notes":"dinner menu","location_name":"test-loc",
"menu_headers_attributes":
    [
       {"name":"ceviches"}
       {"name":"dim sum"}
    ]
}

I have a sort value in the menu_header value. If there is not a sort value, it should auto_increment so that the previous json looks like this:

dinner menu
  -ceviches sort 0
  -dim sum sort 1

I’m assuming in the MenuHeader I could create a before_create to set default values. I’d like something like:

h=MenuHeader.where('menu_id=?',self.associated_model.id).order('sort desc').first

How could I determine the menu_id in the menu_header class? Would this even be available?

thx

Edit: It’s possible to also do this after the insert as an after_create but that just doesn’t seem right.

Answer 1

I’d do it using acts_as_list:

class Menu < ActiveRecord::Base
  has_many :menu_headers, :order => 'sort'
  accepts_nested_attributes_for :menu_headers
end

class MenuHeader < ActiveRecord::Base
  belongs_to :menu
  acts_as_list :scope => :menu
end

If there’s a reason you want to maintain your own list handling (not a terribly complicated thing), digging into the source and doing it however acts_as_list does would most likely be good; they’ve probably iterated on the idea a couple times.