19. Cart update for anonymous users

Adding products

Our website will support purchases by anonymous customers who do not have an account throught the use of cookies (that generate and store unique ids for each user that enters). To facilitate this, first we will implement a system that automatically generates a customer ID upon adding a item to the cart.

Important Note: At present, the shopping cart functionality is restricted to authenticated users (specifically the admin user). Ensure you are logged into your admin account, as the cart will not function without authentication.

We will begin by importing the uuid (Universal Unique Identifier) library into the views.py file. This library will be responsible for generating unique identifiers.

views.py

import uuid

Next, we will modify the is_authenticated condition check within our add_to_cart function to generate a unique customer ID if the user does not have an existing account.

views.py

def add_to_cart(request, product_id):
    if request.method == "POST" and product_id : #? if the user is sending a new product
        data = request.POST.dict() #? converts the request data to a dictionary
        size = data.get('size') #? used get instead of ['size'] as it wont return a error
        color_id = data.get('color')
        if not size: #? only check the size as it only appears after selecting the color
            return redirect('store')
        
        #!getting the client
        answer = redirect('cart') #? to implement cookies we need to edit the redirect response
        if request.user.is_authenticated:
            client = request.user.client
        else :
            if request.COOKIES.get("id_session") : #? checks if there is already a registred anonymous session
                id_session = request.COOKIES.get("id_session")
            else :
                id_session = str(uuid.uuid4()) #? uuid4 guarantees uniqueness and safety
                answer.set_cookie(key="id_session", value=id_session)
            client, created = Client.objects.get_or_create(id_session=id_session) 
            
        order, created = Order.objects.get_or_create(client=client, finished=False)
        item_stock = ItemStock.objects.get(product__id=product_id, size=size, color=color_id) #? In the forms we enter the color, id, and the size
        item_ordered, created = OrderedItem.objects.get_or_create(order=order, itemstock=item_stock) #? adding the product to the cart
        item_ordered.quantity += 1
        item_ordered.save() #? Must save changes made directly to a element
        return answer
    else :
        return redirect('store') #? redirect the user to the store if he didn't choose a product

The modifications implemented in the updated code are detailed below:

• Redirect Initialization:

  • answer = redirect('cart')

    • Initializes a redirect response to the 'cart' view.

• Authenticated User Check:

  • if request.user.is_authenticated:

    • Checks if the user is authenticated.

  • client = request.user.client

    • Retrieves the authenticated user's client object.

• Anonymous User Handling:

  • Check for Existing Anonymous Session:

    • if request.COOKIES.get("id_session"):

      • Checks if an id_session cookie already exists in the user's cookies.

    • id_session = request.COOKIES.get("id_session")

      • Retrieves the existing id_session value.

  • Generate New Anonymous Session ID:

    • else:

      • Executes if no id_session cookie is found.

    • id_session = str(uuid.uuid4())

      • Generates a new unique identifier using uuid4, ensuring a unique ID independent of the user's device.

    • answer.set_cookie(key="id_session", value=id_session)

      • Sets a new cookie with the key id_session and the generated unique ID.

  • Client Object Retrieval/Creation:

    • client, created = Client.objects.get_or_create(id_session=id_session)

      • Retrieves or creates a Client object associated with the id_session. If the Client object does not exist, it will be created.

Upon logging out of the admin account and attempting to add an item to the cart, the following error message will be encountered:

This issue arises because we have not yet adapted the cart view to accommodate anonymous customers.

Upon logging back into the admin account, it will be observed that a new client and order have been created, with the client name displayed as None.

Order list

Client list

Removing products

The process for enabling product removal is akin to the recent implementation. We will proceed to modify the remove_from_cart function accordingly.

views.py

if request.user.is_authenticated:
            client = request.user.client
        else :
            if request.COOKIES.get('id_session') :
                id_session = request.COOKIES.get("id_session")
                client, created = Client.objects.get_or_create(id_session=id_session)
            else : #? if the client enters directly on the cart, whithout generating cookies
                return redirect('store') #? return directly to the store as the cart should be empty

In the updated remove_from_cart function, we have incorporated similar logic to handle anonymous clients. If no id is found (indicating the client accessed the cart directly without adding a product), a redirect to the store is implemented, ensuring an empty cart state.