forms.py 文件源码

def clean(self):
        cleaned_data = super(AddToCartForm, self).clean()
        quantity = cleaned_data.get('quantity')
        if quantity is None:
            return cleaned_data
        try:
            product_variant = self.get_variant(cleaned_data)
        except ObjectDoesNotExist:
            msg = self.error_messages['variant-does-not-exists']
            self.add_error(NON_FIELD_ERRORS, msg)
        else:
            cart_line = self.cart.get_line(product_variant)
            used_quantity = cart_line.quantity if cart_line else 0
            new_quantity = quantity + used_quantity
            try:
                product_variant.check_quantity(new_quantity)
            except InsufficientStock as e:
                remaining = e.item.get_stock_quantity() - used_quantity
                if remaining:
                    msg = self.error_messages['insufficient-stock']
                    self.add_error('quantity', msg % remaining)
                else:
                    msg = self.error_messages['empty-stock']
                    self.add_error('quantity', msg)
        return cleaned_data