TypeError: Object of type Cart is not JSON serializable

Question

I just started using session in Django framework. I have create an object cart from Cart model. And when i wan to set cart inside request.session with session['cart'] = cart, I get this error message: TypeError: Object of type Cart is not JSON serializable

This is my Cart model

class Cart(object):

    def __init__(self):
        self.items = []

    def addItem(self, itemCart):
        try:
            # get index of itemCart if exist
            index = self.items.index(itemCart)
            # itemCart exist then set its quantity
            self.items[index].setQuantity(
                self.items[index].quantity + itemCart.quantity)
        except ValueError:
            # the item does not exits then add to items list
            self.items.append(itemCart)

This is my view when i update the session

cart = Cart()
session['cart'] = cart

And When i run the code i get this error: File "C:\Users\Patrick-PC\AppData\Local\Programs\Python\Python37\lib\json\encoder.py", line 179, in default raise TypeError(f'Object of type {o.class.name} ' TypeError: Object of type Cart is not JSON serializable.

Please help

Answer 1

If Cart is a model, you'll want to inherit from models.Model. That said, you can try:

from django.core import serializers
session['cart'] = serializers.serialize('json', Cart.objects.all())