ShoppingCart

Simple gem which adds shopping cart and checkout ability to your shop.

Add this line to your application's Gemfile to get latest update:

gem 'shopping_cart', github: 'rockandruby/shopping_cart'

or get last stable version

gem 'shopping_cart'

Define root in your routes and run rails g shopping_cart:config to install shopping cart.

Ensure you have flash messages in app/views/layouts/application.html.erb. For example:

    <p class="notice"><%= notice %></p>
    <p class="alert"><%= alert %></p>

Firstly, gem depends on devise. Thus your app must have current_{model_name} method to perform shopping cart functionality. For right now cart is accessible only for signed in users. Devise added as a dependency for cart thus you don't need add devise to your gemfile. All you need - to install device.

In config/initializers you will find shopping_cart initializer. By default, name of your user model is 'User' but you can override it by changing ShoppingCart.user_class = 'User' with proper model name in string format.

By default, you have 4 steps for checkout:

• address
• payment
• shipping
• complete

Payment and shipping are optional. In shopping cart initializer you have ShoppingCart.order_steps = %i(shipping payment). If you want to delete step, just delete it from array. If you want to delete optional steps at all, just comment the array ans you will have only address and complete steps.

When you install shopping cart, you retrieve migrations for default steps. You can delete proper migration for step you want to skip. Then run rails db:migrate to run migrations.

Of course, you can add your own steps. Just put the name of your step to steps' array in initializer and restart your app .

Run rails g shopping_cart:controller MySteps 'first_step' 'second_step' to generate controller, proper actions, views and routes for your steps. Don't forget that steps' names should be equal to names in your initializer.

Don't forget that all entities should be in shopping_cart namespace. For instance, to create model for your steps you suppose to run shopping_cart/YourModelName.

Your step controller will have 3 main methods:

• check_step(:your_step) which checks whether user able to proceed action and returns true/false.
• update_step(:your_step) which allows user to proceed to next step.
• redirect_by_step(:your_step) which redirects to next step.

Below simple example how it works:

 def your_step
 
  return redirect_to :back unless check_step(:your_step)
  
  //do some code
  
 end

 def add_your_step
 
   //do some code
   
   update_step(:your_step)
   
   redirect_by_step(:your_step)
   
 end

You should add the following association for your user model has_many :orders, :class_name => 'ShoppingCart::Order'.

Cart can process any product type quantity, you just need to add the following association to your product model(e.g. Book, Magazine etc.) has_many :order_items, :class_name => 'ShoppingCart::OrderItem', as: :productable. Also your model must have 'price' attribute.

You form should include following fields: hidden field "name='model' value='your model class'" e.g. "value='@book.class'". text field "name='quantity'" and hidden field "name='id' value='@book.id'". For instance,

 =form_tag(shopping_cart.order_items_path, class: 'form-inline') do
 
   =text_field_tag(:quantity, '', class: 'form-control', type: 'number', required: true, min: 1)
   
   =hidden_field_tag(:id, @book.id)
   
   =hidden_field_tag(:model, @book.class)
   
   =submit_tag

 = link_to('cart', shopping_cart.order_items_path)

Submit your form on the following path shopping_cart.order_items_path.

Order details

To get current order just do ShoppingCart::Order.current_order(user) with current user object as argument. AASM used to save states for order. Order has 3 states: 'in_progress', 'placed' and 'canceled' and proper events: 'place_order' and 'cancel_order'. How to use states you can read in aasm docs. Order object has some useful methods:

• subtotal_price raw price of goods without shipping and discount(if present)
• total_price final price including all costs
• order_items_count property to retrieve amount of items in cart

When user adds goods to cart a new order created with 'in_progress' state. It doesn't matter whether user delete all items or not, it can have only one order 'in_progress' unless he place it. It was made to avoid each time order creation.

You can override views and layout for shopping cart by generating them to your project with rails g shopping_cart:views.

Also, you're able to use discount for your cart. Just create the proper discount, for example: ShoppingCart::Discount.create(code: 'verification code', amount: 10), where amount is percentage. If you don't need discount ability, delete the proper button from view.

I18n: Run rails g shopping_cart:translate to generate internationalization file to your app.