Symfony's Service Container provides multiple features to control the creation of objects, allowing you to specify arguments passed to the constructor as well as calling methods and setting parameters.
However, sometimes you need to apply the factory design pattern to delegate the object creation to some special object called "the factory". In those cases, the service container can call a method on your factory to create the object 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:
// src/Email/NewsletterManagerStaticFactory.php
namespace App\Email;
// ...
class NewsletterManagerStaticFactory
{
public static function createNewsletterManager(): NewsletterManager
{
$newsletterManager = new NewsletterManager();
// ...
return $newsletterManager;
}
}
To make the NewsletterManager object available as a service, use the
factory option to define which method of which class must be called to
create its object:
.. configuration-block::
.. code-block:: yaml
# config/services.yaml
services:
# ...
App\Email\NewsletterManager:
# the first argument is the class and the second argument is the static method
factory: ['App\Email\NewsletterManagerStaticFactory', 'createNewsletterManager']
.. code-block:: 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\Email\NewsletterManager">
<!-- the first argument is the class and the second argument is the static method -->
<factory class="App\Email\NewsletterManagerStaticFactory" method="createNewsletterManager"/>
</service>
</services>
</container>
.. code-block:: php
// config/services.php
namespace Symfony\Component\DependencyInjection\Loader\Configurator;
use App\Email\NewsletterManager;
use App\Email\NewsletterManagerStaticFactory;
return function(ContainerConfigurator $container): void {
$services = $container->services();
$services->set(NewsletterManager::class)
// the first argument is the class and the second argument is the static method
->factory([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.
When the static factory method is on the same class as the created instance,
the class name can be omitted from the factory declaration.
Let's suppose the NewsletterManager class has a create() method that needs
to be called to create the object and needs a sender:
// src/Email/NewsletterManager.php
namespace App\Email;
// ...
class NewsletterManager
{
private string $sender;
public static function create(string $sender): self
{
$newsletterManager = new self();
$newsletterManager->sender = $sender;
// ...
return $newsletterManager;
}
}
You can omit the class on the factory declaration:
.. configuration-block::
.. code-block:: yaml
# config/services.yaml
services:
# ...
App\Email\NewsletterManager:
factory: [null, 'create']
arguments:
$sender: '[email protected]'
.. code-block:: 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\Email\NewsletterManager">
<factory method="create"/>
</service>
</services>
</container>
.. code-block:: php
// config/services.php
namespace Symfony\Component\DependencyInjection\Loader\Configurator;
use App\Email\NewsletterManager;
return function(ContainerConfigurator $container): void {
$services = $container->services();
// Note that we are not using service()
$services->set(NewsletterManager::class)
->factory([null, 'create']);
};
It is also possible to use the constructor option, instead of passing null
as the factory class:
.. configuration-block::
.. code-block:: php-attributes
// src/Email/NewsletterManager.php
namespace App\Email;
use Symfony\Component\DependencyInjection\Attribute\Autoconfigure;
#[Autoconfigure(bind: ['$sender' => '[email protected]'], constructor: 'create')]
class NewsletterManager
{
private string $sender;
public static function create(string $sender): self
{
$newsletterManager = new self();
$newsletterManager->sender = $sender;
// ...
return $newsletterManager;
}
}
.. code-block:: yaml
# config/services.yaml
services:
# ...
App\Email\NewsletterManager:
constructor: 'create'
arguments:
$sender: '[email protected]'
.. code-block:: 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\Email\NewsletterManager" constructor="create">
</service>
</services>
</container>
.. code-block:: php
// config/services.php
namespace Symfony\Component\DependencyInjection\Loader\Configurator;
use App\Email\NewsletterManager;
return function(ContainerConfigurator $containerConfigurator) {
$services = $containerConfigurator->services();
$services->set(NewsletterManager::class)
->constructor('create');
};
If your factory is using a regular method instead of a static one to configure and create the service, instantiate the factory itself as a service too. Configuration of the service container then looks like this:
.. configuration-block::
.. code-block:: yaml
# config/services.yaml
services:
# ...
# first, create a service for the factory
App\Email\NewsletterManagerFactory: ~
# second, use the factory service as the first argument of the 'factory'
# option and the factory method as the second argument
App\Email\NewsletterManager:
factory: ['@App\Email\NewsletterManagerFactory', 'createNewsletterManager']
.. code-block:: 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>
<!-- first, create a service for the factory -->
<service id="App\Email\NewsletterManagerFactory"/>
<!-- second, use the factory service as the first argument of the 'factory'
option and the factory method as the second argument -->
<service id="App\Email\NewsletterManager">
<factory service="App\Email\NewsletterManagerFactory"
method="createNewsletterManager"
/>
</service>
</services>
</container>
.. code-block:: php
// config/services.php
namespace Symfony\Component\DependencyInjection\Loader\Configurator;
use App\Email\NewsletterManager;
use App\Email\NewsletterManagerFactory;
return function(ContainerConfigurator $container): void {
$services = $container->services();
// first, create a service for the factory
$services->set(NewsletterManagerFactory::class);
// second, use the factory service as the first argument of the 'factory'
// method and the factory method as the second argument
$services->set(NewsletterManager::class)
->factory([service(NewsletterManagerFactory::class), 'createNewsletterManager']);
};
Suppose you now change your factory method to __invoke() so that your
factory service can be used as a callback:
// src/Email/InvokableNewsletterManagerFactory.php
namespace App\Email;
// ...
class InvokableNewsletterManagerFactory
{
public function __invoke(): NewsletterManager
{
$newsletterManager = new NewsletterManager();
// ...
return $newsletterManager;
}
}
Services can be created and configured via invokable factories by omitting the method name:
.. configuration-block::
.. code-block:: yaml
# config/services.yaml
services:
# ...
App\Email\NewsletterManager:
class: App\Email\NewsletterManager
factory: '@App\Email\InvokableNewsletterManagerFactory'
.. code-block:: 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\Email\NewsletterManager"
class="App\Email\NewsletterManager">
<factory service="App\Email\InvokableNewsletterManagerFactory"/>
</service>
</services>
</container>
.. code-block:: php
// config/services.php
namespace Symfony\Component\DependencyInjection\Loader\Configurator;
use App\Email\NewsletterManager;
use App\Email\NewsletterManagerFactory;
return function(ContainerConfigurator $container): void {
$services = $container->services();
$services->set(NewsletterManager::class)
->factory(service(InvokableNewsletterManagerFactory::class));
};
Instead of using PHP classes as a factory, you can also use :doc:`expressions </service_container/expression_language>`. This allows you to e.g. change the service based on a parameter:
.. configuration-block::
.. code-block:: yaml
# config/services.yaml
services:
App\Email\NewsletterManagerInterface:
# use the "tracable_newsletter" service when debug is enabled, "newsletter" otherwise.
# "@=" indicates that this is an expression
factory: '@=parameter("kernel.debug") ? service("tracable_newsletter") : service("newsletter")'
# you can use the arg() function to retrieve an argument from the definition
App\Email\NewsletterManagerInterface:
factory: "@=arg(0).createNewsletterManager() ?: service("default_newsletter_manager")"
arguments:
- '@App\Email\NewsletterManagerFactory'
.. code-block:: 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\Email\NewsletterManagerInterface">
<!-- use the "tracable_newsletter" service when debug is enabled, "newsletter" otherwise -->
<factory expression="parameter('kernel.debug') ? service('tracable_newsletter') : service('newsletter')"/>
</service>
<!-- you can use the arg() function to retrieve an argument from the definition -->
<service id="App\Email\NewsletterManagerInterface">
<factory expression="arg(0).createNewsletterManager() ?: service("default_newsletter_manager")"/>
<argument type="service" id="App\Email\NewsletterManagerFactory"/>
</service>
</services>
</container>
.. code-block:: php
// config/services.php
namespace Symfony\Component\DependencyInjection\Loader\Configurator;
use App\Email\NewsletterManagerFactory;
use App\Email\NewsletterManagerInterface;
return function(ContainerConfigurator $containerConfigurator) {
$services = $containerConfigurator->services();
$services->set(NewsletterManagerInterface::class)
// use the "tracable_newsletter" service when debug is enabled, "newsletter" otherwise.
->factory(expr("parameter('kernel.debug') ? service('tracable_newsletter') : service('newsletter')"))
;
// you can use the arg() function to retrieve an argument from the definition
$services->set(NewsletterManagerInterface::class)
->factory(expr("arg(0).createNewsletterManager() ?: service('default_newsletter_manager')"))
->args([
service(NewsletterManagerFactory::class),
])
;
};
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
option. For example, suppose the createNewsletterManager() method in the
previous examples takes the templating service as an argument:
.. configuration-block::
.. code-block:: yaml
# config/services.yaml
services:
# ...
App\Email\NewsletterManager:
factory: ['@App\Email\NewsletterManagerFactory', createNewsletterManager]
arguments: ['@templating']
.. code-block:: 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\Email\NewsletterManager">
<factory service="App\Email\NewsletterManagerFactory" method="createNewsletterManager"/>
<argument type="service" id="templating"/>
</service>
</services>
</container>
.. code-block:: php
// config/services.php
namespace Symfony\Component\DependencyInjection\Loader\Configurator;
use App\Email\NewsletterManager;
use App\Email\NewsletterManagerFactory;
return function(ContainerConfigurator $container): void {
$services = $container->services();
$services->set(NewsletterManager::class)
->factory([service(NewsletterManagerFactory::class), 'createNewsletterManager'])
->args([service('templating')])
;
};