Using a Factory to Create Services
Using a Factory to Create Services¶
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:
1 2 3 4 5 6 7 8 9 10 11 | class NewsletterManagerFactory
{
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
NewsletterManagerFactory::createNewsletterManager()
factory method:
- YAML
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services: app.newsletter_manager: class: AppBundle\Email\NewsletterManager # call a static method factory: ['AppBundle\Email\NewsletterManager', create] app.newsletter_manager_factory: class: AppBundle\Email\NewsletterManagerFactory app.newsletter_manager: class: AppBundle\Email\NewsletterManager # call a method on the specified service factory: ['@app.newsletter_manager_factory', createNewsletterManager]
- XML
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<?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.newsletter_manager" class="AppBundle\Email\NewsletterManager"> <!-- call a static method --> <factory class="AppBundle\Email\NewsletterManager" method="create" /> </service> <service id="app.newsletter_manager_factory" class="AppBundle\Email\NewsletterManagerFactory" /> <service id="app.newsletter_manager" class="AppBundle\Email\NewsletterManager"> <!-- call a method on the specified service --> <factory service="app.newsletter_manager_factory" method="createNewsletterManager" /> </service> </services> </container>
- PHP
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use Symfony\Component\DependencyInjection\Definition; // ... $definition = new Definition('AppBundle\Email\NewsletterManager'); // call a static method $definition->setFactory(array('AppBundle\Email\NewsletterManager', 'create')); $container->setDefinition('app.newsletter_manager', $definition); $container->register('app.newsletter_manager_factory', 'AppBundle\Email\NewsletterManagerFactory'); $newsletterManager = new Definition('AppBundle\Email\NewsletterManager'); // call a method on the specified service $newsletterManager->setFactory(array( new Reference('app.newsletter_manager_factory'), 'createNewsletterManager' )); $container->setDefinition('app.newsletter_manager', $newsletterManager);
Note
When using a factory to create services, the value chosen for the class
option 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.
Passing Arguments to the Factory Method¶
If you need to pass arguments to the factory method, you can use the arguments
options inside the service container. For example, suppose the createNewsletterManager()
method in the previous example takes the templating
service as an argument:
- YAML
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services: # ... app.newsletter_manager: class: AppBundle\Email\NewsletterManager factory: ['@newsletter_manager_factory', createNewsletterManager] arguments: ['@templating']
- XML
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<?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.newsletter_manager" class="AppBundle\Email\NewsletterManager"> <factory service="app.newsletter_manager_factory" method="createNewsletterManager"/> <argument type="service" id="templating"/> </service> </services> </container>
- PHP
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use Symfony\Component\DependencyInjection\Reference; use Symfony\Component\DependencyInjection\Definition; // ... $newsletterManager = new Definition('AppBundle\Email\NewsletterManager', array( new Reference('templating') )); $newsletterManager->setFactory(array( new Reference('app.newsletter_manager_factory'), 'createNewsletterManager' )); $container->setDefinition('app.newsletter_manager', $newsletterManager);
This work, including the code samples, is licensed under a Creative Commons BY-SA 3.0 license.