Thanks to visit codestin.com
Credit goes to github.com

Skip to content

[DoctrineBridge] update doctrine event listeners doc for Symfony 4.2 change #9973

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 4 commits into from
Jun 29, 2018
Merged

[DoctrineBridge] update doctrine event listeners doc for Symfony 4.2 change #9973

Changes from all commits
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
601450e
Update event_listeners_subscribers.rst
dmaicher Jun 27, 2018
d8bb849
Reworded and added the versionadded directive
javiereguiluz Jun 28, 2018
b56ef9e
Update event_listeners_subscribers.rst
javiereguiluz Jun 28, 2018
4409fd6
Explain that lazy listeners are mandatory, not default
javiereguiluz Jun 29, 2018
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
62 changes: 11 additions & 51 deletions doctrine/event_listeners_subscribers.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -186,57 +186,17 @@ interface and have an event method for each event it subscribes to::

For a full reference, see chapter `The Event System`_ in the Doctrine documentation.

Lazy loading for Event Listeners
--------------------------------
Performance Considerations
--------------------------

One subtle difference between listeners and subscribers is that Symfony can load
entity listeners lazily. This means that your listener class will only be fetched
from the service container (and thus be instantiated) once the event it is linked
to actually fires.
One important difference between listeners and subscribers is that Symfony loads
entity listeners lazily. This means that the listener classes are only fetched
from the service container (and instantiated) if the related event is actually
fired.

Lazy loading might give you a slight performance improvement when your listener
runs for events that rarely fire. Also, it can help you when you run into
*circular dependency issues* that may occur when your listener service in turn
depends on the DBAL connection.
That's why it is preferable to use entity listeners instead of subscribers
whenever possible.

To mark a listener service as lazily loaded, just add the ``lazy`` attribute
to the tag like so:

.. configuration-block::

.. code-block:: yaml

services:
App\EventListener\SearchIndexer:
tags:
- { name: doctrine.event_listener, event: postPersist, lazy: true }

.. code-block:: xml

<?xml version="1.0" ?>
<container xmlns="http://symfony.com/schema/dic/services"
xmlns:doctrine="http://symfony.com/schema/dic/doctrine">

<services>
<service id="App\EventListener\SearchIndexer" autowire="true">
<tag name="doctrine.event_listener" event="postPersist" lazy="true" />
</service>
</services>
</container>

.. code-block:: php

use App\EventListener\SearchIndexer;

$container
->autowire(SearchIndexer::class)
->addTag('doctrine.event_listener', array('event' => 'postPersist', 'lazy' => 'true'))
;

.. note::

  Marking an event listener as ``lazy`` has nothing to do with lazy service
definitions which are described :doc:`in their own section </service_container/lazy_services>`

.. _`The Event System`: http://docs.doctrine-project.org/projects/doctrine-orm/en/latest/reference/events.html
.. _`the Doctrine Documentation`: http://docs.doctrine-project.org/projects/doctrine-orm/en/latest/reference/events.html#entity-listeners
.. versionadded:: 4.2
Starting from Symfony 4.2, Doctrine entity listeners are always lazy. In
previous Symfony versions this behavior was configurable.