.. index:: single: DependencyInjection; Factories
Symfony's Service Container provides a powerful way of controlling the creation of objects, allowing you to specify arguments passed to the constructor as well as calling methods and setting parameters. Sometimes, however, this will not provide you with everything you need to construct your objects. For this situation, you can use a factory to create the object and tell the service container to call a method on the factory rather than directly instantiating the class.
Suppose you have a factory that configures and returns a new NewsletterManager
object by calling the static createNewsletterManager() method:
class NewsletterManagerStaticFactory
{
public static function createNewsletterManager()
{
$newsletterManager = new NewsletterManager();
// ...
return $newsletterManager;
}
}
To make the NewsletterManager object available as a service, you can
configure the service container to use the
NewsletterManagerStaticFactory::createNewsletterManager() factory method:
.. configuration-block::
.. code-block:: yaml
# app/config/services.yml
services:
# ...
AppBundle\Email\NewsletterManager:
# call the static method that creates the object
factory: ['AppBundle\Email\NewsletterManagerStaticFactory', createNewsletterManager]
# define the class of the created object
class: AppBundle\Email\NewsletterManager
.. code-block:: xml
<!-- app/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="AppBundle\Email\NewsletterManager"
class="AppBundle\Email\NewsletterManager">
<!-- call the static method that creates the object -->
<factory class="AppBundle\Email\NewsletterManagerStaticFactory" method="createNewsletterManager" />
<!-- starting from Symfony 3.3, if the factory class is the same as the service
class, you can omit the 'class' attribute and define just the 'method' attribute:
<factory method="createNewsletterManager" />
-->
</service>
</services>
</container>
.. code-block:: php
// app/config/services.php
use AppBundle\Email\NewsletterManager;
use AppBundle\Email\NewsletterManagerStaticFactory;
// ...
$container->register(NewsletterManager::class, NewsletterManager::class)
// call the static method
->setFactory(array(NewsletterManagerStaticFactory::class, 'createNewsletterManager'));
Note
When using a factory to create services, the value chosen for class has no effect on the resulting service. The actual class name only depends on the object that is returned by the factory. However, the configured class name may be used by compiler passes and therefore should be set to a sensible value.
If your factory is not using a static function to configure and create your service, but a regular method, you can instantiate the factory itself as a service too. Later, in the ":ref:`factories-passing-arguments-factory-method`" section, you learn how you can inject arguments in this method.
Configuration of the service container then looks like this:
.. configuration-block::
.. code-block:: yaml
# app/config/services.yml
services:
# ...
AppBundle\Email\NewsletterManagerFactory: ~
AppBundle\Email\NewsletterManager:
# call a method on the specified factory service
factory: 'AppBundle\Email\NewsletterManagerFactory:createNewsletterManager'
class: AppBundle\Email\NewsletterManager
.. code-block:: xml
<!-- app/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="AppBundle\Email\NewsletterManagerFactory" />
<service id="AppBundle\Email\NewsletterManager"
class="AppBundle\Email\NewsletterManager">
<!-- call a method on the specified factory service -->
<factory service="AppBundle\Email\NewsletterManagerFactory"
method="createNewsletterManager"
/>
</service>
</services>
</container>
.. code-block:: php
// app/config/services.php
use AppBundle\Email\NewsletterManager;
use AppBundle\Email\NewsletterManagerFactory;
use Symfony\Component\DependencyInjection\Reference;
// ...
$container->register(NewsletterManagerFactory::class);
$container->register(NewsletterManager::class, NewsletterManager::class)
// call a method on the specified factory service
->setFactory(array(
new Reference(NewsletterManagerFactory::class),
'createNewsletterManager',
));
Note
The traditional configuration syntax in YAML files used an array to define the factory service and the method name:
# app/config/services.yml
AppBundle\Email\NewsletterManager:
class: AppBundle\Email\NewsletterManager
# new syntax
factory: 'AppBundle\Email\NewsletterManagerFactory:createNewsletterManager'
# old syntax
factory: ['@AppBundle\Email\NewsletterManagerFactory', createNewsletterManager]Tip
Arguments to your factory method are :ref:`autowired <services-autowire>` if that's enabled for your service.
If you need to pass arguments to the factory method you can use the arguments
options. For example, suppose the createNewsletterManager() method in the previous
example takes the templating service as an argument:
.. configuration-block::
.. code-block:: yaml
# app/config/services.yml
services:
# ...
AppBundle\Email\NewsletterManager:
class: AppBundle\Email\NewsletterManager
factory: 'AppBundle\Email\NewsletterManagerFactory:createNewsletterManager'
arguments: ['@templating']
.. code-block:: xml
<!-- app/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="AppBundle\Email\NewsletterManager"
class="AppBundle\Email\NewsletterManager">
<factory service="AppBundle\Email\NewsletterManagerFactory" method="createNewsletterManager"/>
<argument type="service" id="templating"/>
</service>
</services>
</container>
.. code-block:: php
// app/config/services.php
use AppBundle\Email\NewsletterManager;
use AppBundle\Email\NewsletterManagerFactory;
use Symfony\Component\DependencyInjection\Reference;
// ...
$container->register(NewsletterManager::class, NewsletterManager::class)
->addArgument(new Reference('templating'))
->setFactory(array(
new Reference(NewsletterManagerFactory::class),
'createNewsletterManager',
));