Question

In this code:

<

    % @products.each do |product| %>
      <div class="entry">
        <%= image_tag(product.image_url) %>
        <h3><%= product.title %></h3>
        <p><%= sanitize(product.description) %></p>
        <div class="price_line">
          <span class="price"><%= number_to_currency(product.price) %></span>
    <!-- START_HIGHLIGHT -->
          <%= button_to 'Add to Cart', line_items_path(product_id: product),
            remote: true %>
    <!-- END_HIGHLIGHT -->
        </div>
      </div>
    <% end %>

At the bottom where we have button_to method with the params passed to it:

    <%= button_to 'Add to Cart', line_items_path(product_id: product),
        remote: true %>

Looking at the code, here is my understanding of what is going on, Did I understand it correctly or I have missed something?

In that code we are creating a button with text of “Add to Cart” and then we are
passing the product_id of the prodcut varaible to it, which is coming
from that for-each loop at the top and telling it go to link_items page with a
POST method for a product with ID of product_id .

Another question: in the lines_items_path could we just pass product.product_id ? or that wouldn’t work?

Answer 1

I think it is an example from the Agile Web Development with Rails book. I read it long time ago… if I remember it right, there are products, orders and line_items.

if you call rake routes you will se that line_items_path, as POST, is the route for thecreate action in the line_items_controller. More details: CRUD verbs and actions

So, you are passing the product_id to the create action, where you should have something like:

def create
  product = Product.find(params[:product_id])
...
end