get all products of category and child categories (rails, awesome_nested_set)

Question

having an e-commerce application under development i am trying to get my head around the following problem: I have my categories realized through the awesome_nested_set plugin.

Answer 1

The key with awesome_nested_set is to use a range in the lft column. Here's a code sample of how I do it with a direct association (category has_many articles)

  module Category
    extend ActiveSupport::Concern
    included do
      belongs_to :category
      scope :sorted, includes(:category).order("categories.lft, #{table_name}.position")
    end

    module ClassMethods
      def tree(category=nil) 
        return scoped unless category
        scoped.includes(:category).where([
          "categories.tree_id=1 AND categories.lft BETWEEN ? AND ?", 
          category.lft, category.rgt
        ])
      end
    end # ClassMethods
  end

Then somewhere in a controller

@category = Category.find_by_name("fruits")
@articles = Article.tree(@category) 

that will find all articles under the categories apples, oranges, bananas, etc etc. You should adapt that idea with a join on categorizations (but are you sure you need a many to many relationship here?)

Anyway I would try this :

class Product < AR
      has_many :categorizations

      def self.tree(category=nil) 
        return scoped unless category
        select("distinct(products.id), products.*").
        joins(:categorizations => :category).where([
          "categories.lft BETWEEN ? AND ?", category.lft, category.rgt
        ])
      end
end

Let me know if there's any gotcha