Issue with Dependency Injection in Custom Price Modificator

[AlephCode]

Hello Pimcore Community,

I am currently developing a custom price modificator named Shipping for the cart system (specifically on the price calculator) in Pimcore. My goal is to inject a service called LocalShippingService into this modificator to utilize some of its specific functionalities.

Context
I have configured my Shipping modificator in the Pimcore system as follows:

price_calculator:
    factory_id: Pimcore\Bundle\EcommerceFrameworkBundle\CartManager\CartPriceCalculatorFactory
    factory_options:
        class: Pimcore\Bundle\EcommerceFrameworkBundle\CartManager\CartPriceCalculator
    modificators:
        shipping:
            class: App\Ecommerce\Cart\PriceModifier\Shipping

The issue arises when I attempt to inject the LocalShippingService directly into the constructor of Shipping. The CartPriceCalculator class, which is responsible for creating the modificators, does not pass this service to the constructor, resulting in a "Too few arguments" error, as the constructor expects to receive the service as an argument.

Specific Problem
When CartPriceCalculator instances the modificators, there is no provision to inject services or additional dependencies other than those explicitly configured in modificators:

protected function buildModificator(array $config): CartPriceModificatorInterface
{
    $className = $config['class'];
    if (!empty($config['options'])) {
        $modificator = new $className($config['options']);
    } else {
        $modificator = new $className();
    }

    return $modificator;
}

I attempted to use a custom class instead of CartPriceCalculator by extending it and injecting the LocalShippingService into its constructor. However, this resulted in an error stating that the constructor is not compatible with the CartPriceCalculatorInterface.

Requests for Help
Is there a standard or Pimcore-recommended way to handle dependency injection in price modificators? I am looking for a solution that allows me to integrate services without modifying Pimcore's core logic.

Has anyone faced and overcome a similar issue when trying to extend cart functionality or working with custom modificators? Any code examples or guidance would be greatly appreciated.

Would modifying CartPriceCalculator to allow dependency injections be advisable, or is there a better practice for handling such configuration needs?

Thank you in advance for any help or direction you can provide.

[AlephCode]

@mattamon Could you lend me a hand with this at some point, please? I would greatly appreciate it if you could provide me with some guidance on how to use my service within my Modifier class, as I won't be using a static shipping fee but rather it should be calculated using the service I want to inject.

[mattamon]

Hey @AlephCode

Have you tried to apply the rules via Pricing Rules yet? https://pimcore.com/docs/platform/Ecommerce_Framework/Working_with_Prices/Pricing_Rules

The way I did it in my last project was to implement a custom pricing rules condition and action. Maybe this suits your use-case.

For the shipping class I am not sure it was intended to be extended. Another way would maybe to decorate it or use a setter injection via symfony instead of injecting it into the constructor.
I linked the docs.

https://symfony.com/doc/current/service_container/service_decoration.html

https://symfony.com/doc/current/service_container/calls.html

[AlephCode]

I'm going to take a look at pricing rules to see if it can be useful, but I already have a service (LocalShippingService) that helps me determine the charge I should make to my customer for their shipment based on various parameters. That’s why I wanted to inject it into the constructor of my modificator. I tried using setter injection along with calls to invoke the setter, but it only works when I instantiate Shipping myself. However, the class that instantiates the modificators is Pimcore\Bundle\EcommerceFrameworkBundle\CartManager\CartPriceCalculator, and when this class creates an instance, it does not execute my call, meaning the setter does not inject my LocalShippingService dependency. I also tried creating my own modificator instead of extending it from \Pimcore\Bundle\EcommerceFrameworkBundle\CartManager\CarPriceModificator\Shipping and implementing the interface Pimcore\Bundle\EcommerceFrameworkBundle\CartManager\CartPriceModificator\ShippingInterface. However, I encounter the same problem: when the CartPriceCalculator instances the modificators, it only considers 2 cases, when creating an empty constructor or when passed ['options']. I tried to extend this class and modify the protected function buildModificator to inject my LocalShippingService from there, but when I wanted to add the instance to the constructor, I got an error stating that the constructor is not compatible with the CartPriceCalculatorInterface.

Do you have any idea what else I could do @mattamon ? Thanks in advance.