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More clear description of factory service creation #7377

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105 changes: 78 additions & 27 deletions service_container/factories.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -13,9 +13,9 @@ 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::
object by calling the static ``createNewsletterManager()`` method::

class NewsletterManagerFactory
class NewsletterManagerStaticFactory
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This class name looks ugly ... but at the same time it's perfectly understandable. I'm divided about it 😕

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Exactly my thought, I'm happy to change it either way ;].

{
public static function createNewsletterManager()
{
Expand All @@ -29,45 +29,98 @@ object::

To make the ``NewsletterManager`` object available as a service, you can
configure the service container to use the
``NewsletterManagerFactory::createNewsletterManager()`` factory method:
``NewsletterManagerStaticFactory::createNewsletterManager()`` factory method:

.. configuration-block::

.. code-block:: yaml

# app/config/services.yml

services:
app.newsletter_manager:
class: AppBundle\Email\NewsletterManager
# call a static method
factory: ['AppBundle\Email\NewsletterManager', create]
# call the static method
factory: ['AppBundle\Email\NewsletterManagerStaticFactory', createNewsletterManager]

.. code-block:: xml

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we should add a comment containing the filename like this:

<!-- app/config/services.xml -->

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Can you please add this for the other formats too (using config.yml and config.php respectively)?

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I've done this. Am however wondering whether it's not app/config/services.yml and app/config/services.php to be exactly?

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Of course, you are absolutely right. Sorry for the confusion.

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No worries ;].

<!-- 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="app.newsletter_manager" class="AppBundle\Email\NewsletterManager">
<!-- call the static method -->
<factory class="AppBundle\Email\NewsletterManagerStaticFactory" method="createNewsletterManager" />
</service>
</services>
</container>

.. code-block:: php

// app/config/services.php

use AppBundle\Email\NewsletterManager;
use AppBundle\Email\NewsletterManagerStaticFactory;
use Symfony\Component\DependencyInjection\Definition;
// ...

$definition = new Definition(NewsletterManager::class);
// call the static method
$definition->setFactory(array(NewsletterManagerStaticFactory::class, 'createNewsletterManager'));

$container->setDefinition('app.newsletter_manager', $definition);

.. 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,
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About this:

However, the configured class name may be used by compiler passes and therefore should be set to a sensible value.

Should I open a Symfony code issue to improve this behavior and make this class optional?

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(This note was already there, don't know why it is marked as new by the diff.)

I do however believe the note is still valid, because it might be handy to use the class definition somewhere in a compiler pass.

On the other hand, it might be good to check why no active validation is done on the return type of the creation method...

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:
app.newsletter_manager_factory:
class: AppBundle\Email\NewsletterManagerFactory

app.newsletter_manager:
class: AppBundle\Email\NewsletterManager
# call a method on the specified service
# call a method on the specified factory service
factory: 'app.newsletter_manager_factory:createNewsletterManager'

.. 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="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 -->
<!-- call a method on the specified factory service -->
<factory service="app.newsletter_manager_factory"
method="createNewsletterManager"
/>
Expand All @@ -77,50 +130,42 @@ configure the service container to use the

.. code-block:: php

// app/config/services.php

use AppBundle\Email\NewsletterManager;
use AppBundle\Email\NewsletterManagerFactory;
use Symfony\Component\DependencyInjection\Definition;
// ...

$definition = new Definition(NewsletterManager::class);
// call a static method
$definition->setFactory(array(NewsletterManager::class, 'create'));

$container->setDefinition('app.newsletter_manager', $definition);

$container->register('app.newsletter_manager_factory', NewsletterManagerFactory::class);

$newsletterManager = new Definition(NewsletterManager::class);

// call a method on the specified service
// call a method on the specified factory 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.

.. note::

The traditional configuration syntax in YAML files used an array to define
the factory service and the method name:

.. code-block:: yaml

# app/config/services.yml

app.newsletter_manager:
# new syntax
factory: 'app.newsletter_manager_factory:createNewsletterManager'
# old syntax
factory: ['@app.newsletter_manager_factory', createNewsletterManager]

.. _factories-passing-arguments-factory-method:

Passing Arguments to the Factory Method
---------------------------------------

Expand All @@ -132,6 +177,8 @@ method in the previous example takes the ``templating`` service as an argument:

.. code-block:: yaml

# app/config/services.yml

services:
# ...

Expand All @@ -142,6 +189,8 @@ method in the previous example takes the ``templating`` service as an argument:

.. 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"
Expand All @@ -159,6 +208,8 @@ method in the previous example takes the ``templating`` service as an argument:

.. code-block:: php

// app/config/services.php

use AppBundle\Email\NewsletterManager;
use Symfony\Component\DependencyInjection\Reference;
use Symfony\Component\DependencyInjection\Definition;
Expand Down