I have Four models.

Product Category Categorization Images

Product.rb

has_many  :images 
has_many  :categorizations
has_many  :categories, :through => :categorizations

Category.rb

has_many :categorizations
has_many :products, :through => :categorizations

Categorization.rb

belongs_to :category
belongs_to :product

Image.rb

belongs_to :product

When a user clicks to see a product, I want to have a section on the bottom that shows images similar products (based on same category/categories).

I guess my problem is that there are so many nested relationships that I don't know how to extract the relationships out.

Any help is appreciated. Thanks.

• ruby-on-rails

Just think of what object you are currently working with and what object you need to access. In this case I assume you set up @product in the controller, and it seems that you want a collection @similar_products that you then loop through on the bottom of the page.

We have a product to work with at the beginning. From this, we want products that are in the same categories as the product. So, in your controller do

@similar_products = @product.categories.inject({}) do |result_hash, category|
    result_hash[category.name.to_sym] => category.products.reject {|p| p == @product}
    result_hash
end

So what we end up with is something that looks like this:

{:category_1 => [product1, product2, product3], :category_2 => [product4,product5]...}

I might recommend limiting the number of products for each category to something like 5 by changing the result_hash assignment to

result_hash[category.name.to_sym] => category.products[0..4]

Now in your view you can loop through the products by category if you like:

<% @similar_products.each do |k,product_array| # remember that the key is the name and the value is an array %>
    <% product_array.each do |product| %>
        <img src="<%= product.image.path %>" />
    <% end %>
<% end %>