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Service Method Calls and Setter Injection

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Service Method Calls and Setter Injection¶

Tip

If you're using autowiring, you can use @required to automatically configure method calls.

Usually, you'll want to inject your dependencies via the constructor. But sometimes, especially if a dependency is optional, you may want to use "setter injection". For example:

namespace App\Service;

use Psr\Log\LoggerInterface;

class MessageGenerator
{
    private $logger;

    public function setLogger(LoggerInterface $logger)
    {
        $this->logger = $logger;
    }

    // ...
}

To configure the container to call the setLogger method, use the calls key:

YAML

# config/services.yaml
services:
    App\Service\MessageGenerator:
        # ...
        calls:
            - method: setLogger
              arguments:
                  - '@logger'

XML

<!-- config/services.xml -->
<?xml version="1.0" encoding="UTF-8" ?>
<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
        https://symfony.com/schema/dic/services/services-1.0.xsd">

    <services>
        <service id="App\Service\MessageGenerator">
            <!-- ... -->
            <call method="setLogger">
                <argument type="service" id="logger"/>
            </call>
        </service>
    </services>
</container>

PHP

// config/services.php
use App\Service\MessageGenerator;
use Symfony\Component\DependencyInjection\Reference;

$container->register(MessageGenerator::class)
    ->addMethodCall('setLogger', [new Reference('logger')]);

This work, including the code samples, is licensed under a Creative Commons BY-SA 3.0 license.