You are browsing the Symfony 4 documentation, which changes significantly from Symfony 3.x. If your app doesn't use Symfony 4 yet, browse the Symfony 3.4 documentation.

Service Method Calls and Setter Injection

4.1 version

Maintained

2.8 3.4 4.2 master

Unmaintained

2.7 3.2 3.3 4.0

edit this page

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
        http://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', array(new Reference('logger')));

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