Undefined method 'find'

Hello, I am following the guide in AWDWR for the shopping cart in Chapter 8 Iteration C2. I have the the cart and cart_item models set up as shown below, but am receiving the error 'undefined method `find' for #<CartItem:0xb6e7d644>' when I try to add to my cart. Here is the extract:

app/models/cart.rb:10:in `add_product' app/controllers/store_controller.rb:9:in `add_to_cart' -e:2:in `load' -e:2

Here is my Cart model:

class Cart   attr_reader :items

  def initialize     @items =   end

  def add_product(product)     current_item = @items.find {|item| item.product == product}     if current_item       current_item.increment_quantity     else       @items << CartItem.new(product)     end   end end

And here is the CartItem model:

class CartItem

  attr_reader :product, :quantity

  def initialize(product)     @product = product     @quantity = 1   end

  def increment_quantity     @quantity += 1   end

  def title     @product.title   end

  def price     @product.price * @quantity   end end

Can somebody point me in the right direction as to what is throwing this error? I tried creating a method called 'find' in the CartItem model just to see if that did anything, but didn't have much luck.

Never mind...found the problem. Although I am storing the session information in my database, it seems as though running 'rake db:sessions:clear' did what it is supposed to do, but there was somehow session data in my browser yet. According to the book, one only needs to run the rake task and then refresh the page.

Once I actually closed my browser and reopened it, everything worked as designed. Perhaps I have misread how storing the session data in the database instead of cookies works...Is there something that changed with Rails 2.0.2?

Never mind...found the problem. Although I am storing the session information in my database, it seems as though running 'rake db:sessions:clear' did what it is supposed to do, but there was
somehow session data in my browser yet. According to the book, one only needs to run the rake task and then refresh the page.

Once I actually closed my browser and reopened it, everything worked
as designed. Perhaps I have misread how storing the session data in the database instead of cookies works...Is there something that changed
with Rails 2.0.2?

Yes - by default in rails 2.0.2 the entire session is in the cookie. On the way you've found out the pitfall of putting complex objects in
the session: you can get nonsensical and confusing results when the
code changes but the user still has an old session with the old model.

Fred