How to override product_url in Spree 2.x / Rails 4 to make more SEO friendly?

Question

After a lot of research I figured it out.

There are two steps in this process. The first is to create a route that matches the new product route.

So go into your routes.rb and in this section:

mount Spree::Core::Engine, :at => '/' 
 # Spree Specific routes here
end

Add this line: get ':id/p' => 'spree/products#show'

So now it looks like this:

mount Spree::Core::Engine, :at => '/' 
 # Spree Specific routes here
 get ':id/p' => 'spree/products#show'
end

At this point you should be able to visit the product page with the new url structure: /product-name-here/p

Problem now is that all of links automatically generated by spree to product pages will still use the old URL structure, so we must fix that as well. To do this we're going to create an over-ride for the product_path function that spree uses to generate these urls. Create a new directory in your helpers folder called "spree" and then a new file inside that directory called products_helper.rb

Now in this file app/helpers/spree/products_helper.rb add the following code:

module Spree::ProductsHelper

  def product_path(product)
    "/#{product.permalink}/p"
  end

end

And that's it. Now all of the links spree generates will use that new URL structure. You can modify this guide to make whatever url structure you want within spree for your products.

Troubleshooting tip:

Not sure why, but after I created the ProductsHelper I was getting an error when I went to the cart about an undefined function: line_item_description_text

I don't use the normal spree descriptions in my cart, so to fix this I just added:

def line_item_description_text (var)
  ""
end