Nested Resource Creation in Parent Form

I have a class called Quote which has_many :line_items, as: :line_itemable (line_items are polymorphic). A quote must have at least one line_item upon creation, so in my Quote creation form I have a section dedicated to adding line items. My routes look like this:

resources :quotes, shallow: true do
  resources :line_items
end

which means my routes look like this:

                     POST  /quotes/:quote_id/line_items(.:format)      line_items#create
new_quote_line_item  GET   /quotes/:quote_id/line_items/new(.:format)  line_items#new

In the line items section of the quote form I have a button that, when clicked, links to the new_quote_line_item controller action to render a line_item creation modal. My issue is that since the quote hasn't been created yet it doesn't have :quote_id to use in the path. How can I go about achieving this the Rails Way™? I was considering using ajax but I'm not sure if that is overkill for this situation. Thanks for your help!

Solution

Ajax

You wouldn't need ajax functionality for this - Ajax only allows you to pull data from the server asynchronously, which essentially means you don't have to reload the page.

Nested Attributes

What you're looking for, as alluded to by atomAltera sounds like accepts_nested_attributes_for - which allows you to create dependent models from the parent

It sounds to me that you'll need to create a quote before you try and populate line_items, which is actually quite simple using ActiveRecord:

#app/models/quote.rb
Class Quote < ActiveRecord::Base
   has_many :line_items
   accepts_nested_attributes_for :line_items
end

#app/controllers/quotes_controller.rb
Class QuotesController < ApplicationController
    def new
       @quote = Quote.new
       @quote.line_items.build
    end

    def create
       @quote = Quote.new(quote_params)
       @quote.save
    end

    private

    def quote_params
        params.require(:quote).permit(:quote, :attributes, :new, line_items_attributes: [:line, :items, :attributes])
    end
end

If you need any further information, please let me know!!