Rails 4堆栈级别太深错误

Question

I'm creating a marketplace app where sellers can list items to sell. I want to create a category dropdown so customers can select a category to shop.

In my listing model, I have a 'category' field. When a user selects a category, I want the view to filter listings from that category.

In my routes.rb:

  get '/listings/c/:category' => 'listings#category', as: 'category'

To create the category menu - in my index.html.erb:

 <%= Listing.uniq.pluck(:category).each do |category| %>
    <%= link_to category, category_path(category: category) %> 
 <% end %>

In my listings controller:

  def category
    @category = category
    @listings = Listing.not_expired.where(:category => @category)
  end

category.html.erb:

<% @listings.each do |listing| %>
        #some html
<% end %>

The homepage category menu shows up. The routes are created. But when I click on the category, the url such as listings/c/necklaces gives me the stack level too deep error.

Answer 1

FYI "Stack Level Too Deep" basically means you have an infinite loop in your code somewhere

--

From what I can see, the error will be here:

def category
    @category = category

With this code, you're basically invoking the category method again, which in turn will invoke the category method etc, in a never-ending cycle. This will prevent your application from being able to run without reloading itself in infinite recursion.

You should change it to:

def category
    @category = params[:category]
    @listings = Listing.not_expired.where(:category => @category)
  end

However, a much more refined way would be:

#app/models/category.rb
class Category < ActiveRecord::Base
   has_many :listings do
      def not_available
         #your not available method here
      end
   end
end

#app/models/listing.rb
class Listing < ActiveRecord::Base
   belongs_to :category
end

#app/controllers/your_controller.rb
def category
  @category = Category.find params[:categpry]
  @listings = @category.listings.not_available