Dependency Injection

Overview

In this guide you'll learn how to inject services into other services. You can read more about injecting services in the Symfony documentation.

Prerequisites

To add your own custom service for your plugin, you first need a plugin as a base. Therefore, you can refer to the Plugin Base Guide.

Furthermore, you need a working service. Therefore, you can refer to Adding a custom service guide.

INFO

Refer to this video on Injecting services into a command explaining DI based on the example of a custom CLI command. It is also available on our free online training "Shopware 6 Backend Development".

Injecting another service

This example will be about injecting the SystemConfigService into our ExampleService. First, we are preparing the ExampleService PHP class. Add the SystemConfigService as parameter to the constructor of the service class.

PLUGIN_ROOT/src/Service/ExampleService.php

<?php declare(strict_types=1);

namespace Swag\BasicExample\Service;

use Shopware\Core\System\SalesChannel\SalesChannelContext;
use Shopware\Core\System\SystemConfig\SystemConfigService;

class ExampleService
{
    public function __construct(
        private SystemConfigService $systemConfigService
    ) {
    }

    public function getShopname(SalesChannelContext $context): string
    {
        return $this->systemConfigService->getString('core.basicInformation.shopName', $context->getSalesChannel()->getId());
    }
}

Using autowire and autoconfigure

If you previously declared autowire and autoconfigure in your services.xml file, you do not need to do anything else. The SystemConfigService will be injected into the ExampleService automatically.

Explicit declaration

If you declared the service explicitly, you need to add the SystemConfigService as argument to the service.

PLUGIN_ROOT/src/Resources/config/services.xml

<?xml version="1.0" ?>

<container xmlns="http://symfony.com/schema/dic/services"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
           xsi:schemaLocation="http://symfony.com/schema/dic/services http://symfony.com/schema/dic/services/services-1.0.xsd">

    <services>
        <service id="Swag\BasicExample\Service\ExampleService">
            <argument type="service" id="Shopware\Core\System\SystemConfig\SystemConfigService"/>
        </service>
    </services>
</container>