undefined 'items' for nil class - ruby-on-rails

Question

on my e-store website when I try to checkout my cart, I'm getting
undefined method `items' for nil:NilClass.
Although on the error page
I know that my cart is there... but when I call it, it gives me nil
Cart Model
class Cart
attr_reader :items
def self.build_from_hash hash
items = if hash["cart"] then
hash["cart"]["items"].map do |item_data|
CartItem.new item_data["product_id"], item_data["quantity"]
end
else
[]
end
new items
end
def initialize items = []
#items = items
end
def add_item product_id
item = #items.find { |item| item.product_id == product_id }
if item
item.increment
else
#items << CartItem.new(product_id)
end
end
def empty?
#items.empty?
end
def count
#items.length
end
def serialize
items = #items.map do |item|
{
"product_id" => item.product_id,
"quantity" => item.quantity
}
end
{
"items" => items
}
end
def total_price
#items.inject(0) { |sum, item| sum + item.total_price }
end
end
Application Controller
def initialize_cart
#cart = Cart.build_from_hash session
end
Cart Controller
class CartsController < ApplicationController
before_filter :initialize_cart
def add
#cart.add_item params[:id]
session["cart"] = #cart.serialize
product = Product.find params[:id]
redirect_to :back, notice: "Added #{product.name} to cart."
end
def show
end
def checkout
#order_form = OrderForm.new user: User.new
end
end
Order Controller
class OrdersController
def create
#order_form = OrderForm.new(
user: User.new(order_params[:user]),
cart: #cart
)
if #order_form.save
redirect_to '/', notice: "Thank you for placing your order."
#cart.empty?
else
render 'carts/checkout'
end
end
Checkout View
<div class="container-checkout">
<p class="text-title"> You are checking out the following: </p>
<table class="table table-striped">
<thead class="name-table">
<tr>
<td> Image </td>
<td> Name </td>
<td> Category</td>
<td> Size </td>
<td> Item Price </td>
</tr>
</thead>
<tbody>
<% #cart.items.each do |item| %>
<tr>
<td><img src="<%= item.product.image %>" width="50px"></td>
<td><%= item.product.name.capitalize %></td>
<td><%= item.product.category.name %></td>
<td><%= item.product.size %></td>
<td class="price-item"><%= number_to_currency item.total_price %>
</td>
<% end %>
</tr>
<tr class="total-price total-price-checkout">
<td class="name-table">Total Price</td>
<td class="price-item"><%= number_to_currency #cart.total_price %></td>
</tr>
</tbody>
</table>
</div>
<div class="details-user-form">
<%= form_for #order_form, url: orders_path do |f|%>
<% f.fields_for :user, #order_form.user do |u| %>
<p class="text-title">Fill the form with your details</p>
<p><%= render "orders/errors" %></p>
<p><%= u.text_field :name, placeholder: "Name" %></p>
<p><%= u.text_field :email, placeholder: "Email" %></p>
<p><%= u.text_field :address, placeholder: "Address" %></p>
<p><%= u.text_field :postal_code, placeholder: "Postal code" %></p>
<p><%= u.text_field :city, placeholder: "City" %></p>
<p><%= u.text_field :country, placeholder: "Country" %></p>
<%= f.submit "Place order", class: "order-btn"%><br>
<% end %>
<% end %>
</div>
Any idea of why is it doing so? Also because, it was working before.. I don't know why it stopped.

Answer 1

I think the problem may be that the #cart variable isn't being set in the OrdersController. Setting the variable in CartsController doesn't make it available globally, as it would only be scoped to the controller that created it, in your case the CartsController.
Also, I see that your Cart model is more of a virtual model than an ActiveRecord model, is that the behaviour you were looking for as I believe ActiveRecord already has a lot of the methods you're recreating there.
I'm not totally sure but I think these may be the issues.
UPDATE
I think I found your error.
In your OrdersController you should have a
before_action :initialize_cart
That seems to be coming from your ApplicationController

Answer 2

If you check your checkout method in your CartController, you will see that you did not set #cart. So when you hit the checkout view, it comes to look for the value or #cart in this method. Setting it there, like the code below should clear your error.
def checkout
#order_form = OrderForm.new user: User.new
#cart = # cart object
end