# settings.py

TEMPLATES = [
    {
        "OPTIONS": {
            "context_processors": [
                ...,
                "dj_shop_cart.context_processors.cart", # If you want access to the cart instance in all templates
            ],
        },
    }
]

# models.py

from django.db import models
from dj_shop_cart.cart import CartItem
from dj_shop_cart.protocols import Numeric

class Product(models.Model):
    ...

    def get_price(self, item:CartItem) -> Numeric:
        """The only requirements of the dj_shop_cart package apart from the fact that the products you add
        to the cart must be instances of django based models. You can use a different name for this method
        but be sure to update the corresponding setting (see Configuration). Even if you change the name the
        function signature should match this one.
        """


# views.py

from dj_shop_cart.cart import get_cart_class
from django.http import HttpRequest
from django.views.decorators.http import require_POST
from django.shortcuts import get_object_or_404

from .models import Product

Cart = get_cart_class()


@require_POST
def add_product(request: HttpRequest, product_id:int):
    product = get_object_or_404(Product.objects.all(), pk=product_id)
    quantity = int(request.POST.get("quantity"))
    cart = Cart.new(request)
    cart.add(product, quantity=quantity)
    ...


@require_POST
def remove_product(request: HttpRequest):
    item_id = request.POST.get("item_id")
    quantity = int(request.POST.get("quantity"))
    cart = Cart.new(request)
    cart.remove(item_id=item_id, quantity=quantity)
    ...


@require_POST
def empty_cart(request: HttpRequest):
    Cart.new(request).empty()
    ...