django forloop counter as a variable

Question

So I am trying to make an e-commerce pizza site where when a user adds an item to the basket it is stored as a cookie in the form cart=[{"id":"2","quantity":"1"},{"id":"3","quantity":"5"},{"id":"5","quantity":"3"},{"id":"5","quantity":"3"}]

And my views.py is...

def cart(request):
    cart = request.COOKIES.get('cart')
    cart = json.loads(cart)

    items =[]
    basket=[]
    for i in cart:
        pizza = Product.objects.filter(pk=i['id']).first()
        basket.append(int(i['quantity']))
        items.append(pizza)

    cart = len(cart)

    context = {
        "cart":cart,
        "pizzas":items,
        "basket":basket
    }
    return render (request, "store/cart.html", context)

And my models.py is ...

class Product(models.Model):
    name = models.CharField(max_length=70)
    price = models.IntegerField()
    description = models.CharField(max_length=300)
    image = models.ImageField(upload_to="pizza_images")

    def save(self, *args, **kwargs):
        super().save()
        img = Image.open(self.image.path)

        img.save(self.image.path)

    def __str__(self):
        return f"{self.name}"

In which my template code...

 
                {% for pizza in pizzas %}

                    
                        
                {% endfor %}

            
            
                
                    Item
                    Product
                    Quantity
                    Price
                
            

            
                        {{forloop.counter}}
                        {{pizza.name}}
                        
                            
                            
                                
                                
                            
                        
                        
                            $25

And in the input field I want the quantity of the product to be displayed. The line which says... and for somereason the forloop.counter doesn't get the the value of the list and makes it null.

Any ideas on how i could make it work? Thanks!

user_67579 · Answer

{{ basket.forloop.counter0 }} will not work, since this simply will look if basket has a forloop attribute or item, but that is not the case, since both basket.forloop and basket['forloop'] will raise an error.

It is also not a good idea, what you do here is writing business logic in the template. A template should only contain rendering logic: logic that explains how to render data in a pleaseant way, not what data to render.

You can make use of zip(…) [python-doc] to generate 2-tuples of items, and then enumerate over these 2-tuples in the template:

def cart(request):
    cart = request.COOKIES.get('cart')
    cart = json.loads(cart)

    items = []
    basket = []
    for i in cart:
        pizza = Product.objects.filter(pk=i['id']).first()
        basket.append(int(i['quantity']))
        items.append(pizza)
    cart = len(cart)

    context = {
        "cart":cart,
        'pizzabaskets': zip(items, basket),
    }
    return render (request, 'store/cart.html', context)

and then render this with:

{% for pizza, basket in pizzabaskets %}
  
    {{forloop.counter}}
    {{pizza.name}}
    
      
      
        
        
      
    
    …
{% endfor %}

the basket it is stored as a cookie.

I would advise not to work with cookies. Cookies can easily be manipulated by the user through request forgery. This thus means that a user can alter the cookies and for example make an order with

[{"id":"2","quantity":"-10"},{"id":"3","quantity":"5"},{"id":"5","quantity":"3"}]

so a person can order a negative amount of pizzas to reduce the price. The user has the freedom to submit a different structure and try to look for vulnerabilities. If you want to have data that is attached to the session, it is better to make use of session variables [Django-doc], since these are stored at the server side.

django forloop counter as a variable

1 Answers