Add new cart events for modification of quantity

[aashan10]

CoreShop/src/CoreShop/Component/Order/Cart/CartModifier.php

Lines 68 to 92 in d1822b1

	private function resolveItem(StorageListInterface $storageList, StorageListItemInterface $storageListItem): void
	{
	foreach ($storageList->getItems() as $item) {
	if ($this->cartItemResolver->equals($item, $storageListItem)) {
	$this->cartItemQuantityModifier->modify(
	$item,
	$item->getQuantity() + $storageListItem->getQuantity(),
	);
	return;
	}
	}
	$this->eventDispatcher->dispatch(
	new GenericEvent($storageList, ['item' => $storageListItem]),
	CartEvents::PRE_ADD_ITEM,
	);
	$storageList->addItem($storageListItem);
	$this->eventDispatcher->dispatch(
	new GenericEvent($storageList, ['item' => $storageListItem]),
	CartEvents::POST_ADD_ITEM,
	);
	}

We have events to intercept the addition/removal of items in cart, but there is no way of intercepting if an already existing item in cart has it's quantity changed.

For example, we want to conditionally verify that only x number of products can be added to the cart. An event like coreshop.cart.pre_item_quantity_modified would really be helpful.

[dpfaffenbauer]

Use Form Constraints to do that:

<?php

namespace App\Validator\Constraint;

use Symfony\Component\Validator\Constraint;

class OrderMaxItems extends Constraint
{
    /**
     * @var string
     */
    public $message = 'cart.max_items';

    public function validatedBy()
    {
        return 'order_max_items';
    }

    public function getTargets()
    {
        return self::CLASS_CONSTRAINT;
    }
}

<?php

declare(strict_types=1);

namespace App\Validator\Constraint;

use CoreShop\Bundle\OrderBundle\DTO\AddToCartInterface;
use Symfony\Component\Validator\Constraint;
use Symfony\Component\Validator\ConstraintValidator;
use Webmozart\Assert\Assert;

final class OrderMaxItemsValidator extends ConstraintValidator
{
    public function validate($value, Constraint $constraint)
    {
        /** @var OrderMaxItems $constraint */
        /** @var AddToCartInterface $value */
        Assert::isInstanceOf($constraint, OrderMaxItems::class);
        Assert::isInstanceOf($value, AddToCartInterface::class);

        if (count((array)$value->getCart()->getItems()) >= 6) {
            $this->context->addViolation(
                $constraint->message
            );

            return;
        }
    }
}

# services.yaml
services:
    App\Validator\Constraint\OrderMaxItemsValidator:
        tags:
            - { name: validator.constraint_validator, alias: order_max_items }

# config/validator/AddToCart.yaml
CoreShop\Bundle\OrderBundle\DTO\AddToCart:
  constraints:
    - \App\Validator\Constraint\OrderMaxItems: { groups: [ 'coreshop' ] }