Form with dynamic number of items

Question

Just thinking about the best way to build an Order form that would (from user-perspective):

• Allow adding multiple items.
• Each item has Name, Job Type drop-down and File upload.
• User can add or remove items.
• User must provide at least one item.
• All the items should be validated (eg: Name, JobType and File are required).
• When he hits the Submit, an Order should be created with all the items in it.

---

So the model looks like: User -1---*-Order-1---*- OrderItem-*--1-JobType. Additionally OrderItem includes number of attributes, let's say name, file.

---

Now I would like to have as skinny controller as possible. Better with the 'standard' code like:

class OrdersController < ApplicationController
  def create
    @order = Order.new(params[:order])
    if @order.save
      redirect_to account_url
    else
      flash.now[:error] = "Could not save Order"
      render :action => "new"
    end
  end
end

The most interesting thing is how a view should look like so that rails automatically binds all the values posted to the correct objects?

For now I don't worry about degradation from JavaScript, but rather the template for the items to be added and linking all that with the validation (probably as a partial).

I expect a template to look like the one below, but not sure.

<input type='text' name='order[order_items[name[]]][]' />
<select name='order[order_items[job_type[]]][]'>...</select>
<input type='file' name='order[order_items[file[]]][]' />

I have to clone this template in order to add item using JS.

---

So the answer should:

• Include the view or part of it that demonstrates:
  • correct binding of the post values;
  • correct validation for all items;
• Include related part of model.
• Include changes to the controller IF and ONLY IF necessary.
• (JavaScript is not required)

Ideally I would like to see a sample if somebody knows one (maybe somewhere on GitHub).

And the last note, please, check your solutions before posting.

Thanks,
Dmitriy.

Answer 1

Not answering the question directly, but here are some sources to get you there:

• Railscasts: Nested Model Form Part 1
• Railscasts: Nested Model Form Part 2
• Railscasts: Complex Forms Part 3

On a personal note. Your question comes across as asking for someone to do your work for you. I would gladly post an answer to cover all your needs if I was on the clock.