问题描述
我已经为Doctrine onFlush事件侦听器创建了一个服务。在这个听众中，我想引用我在另一个服务中的一个常见的功能来检查实体的快捷方式路径。那个其他服务使用实体管理器来执行此操作，因此该其他服务的服务定义会将doctrine实体管理器作为构造函数参数进行注入。但是，如果我在主要的onFlush事件监听器中包含这个其他服务，我会收到关于循环引用的讨厌的错误。
I have created a service for a Doctrine onFlush event listener. In this listener I would like to reference a common function I have in another service to check the entity's shortcut path. That other service uses the entity manager to do this, so the service definition for that other service injects the doctrine entity manager as a constructor argument. But if I include that other service in my main onFlush event listener, I get a nasty error about circular references.
code> entity_helper 服务接受实体管理器的集合函数 setEntityManager（$ entityManager）。但是这意味着每当我在其他地方使用这个 entity_helper 服务时，我必须始终传入EntityManager。也许没关系，但这是唯一的解决方案吗？我的逻辑/理解开始有什么问题吗？ （我是Symfony的新人，所以我经常出错）。
I could make this entity_helper service accept the Entity Manager in a set function setEntityManager($entityManager). But that means whenever I use this entity_helper service anywhere else, I have to always pass in the EntityManager. Maybe that's okay, but is that the only solution here? Is there something wrong with my logic/understanding to begin with? (I am new to Symfony so I'm frequently wrong).
展览A：讨厌的错误
Fatal error: Uncaught exception 'Symfony\Component\DependencyInjection\Exception\ServiceCircularReferenceException' with message 'Circular reference detected for service "doctrine.dbal.cms_connection", path: "doctrine.dbal.cms_connection".' in /var/www/core/cms/vendor/symfony/symfony/src/Symfony/Component/DependencyInjection/Dumper/PhpDumper.php:456 Stack trace: #0 /var/www/core/cms/vendor/symfony/symfony/src/Symfony/Component/DependencyInjection/Dumper/PhpDumper.php(604): Symfony\Component\DependencyInjection\Dumper\PhpDumper->addServiceInlinedDefinitionsSetup('doctrine.dbal.c...', Object(Symfony\Component\DependencyInjection\Definition)) #1 /var/www/core/cms/vendor/symfony/symfony/src/Symfony/Component/DependencyInjection/Dumper/PhpDumper.php(630): Symfony\Component\DependencyInjection\Dumper\PhpDumper->addService('doctrine.dbal.c...', Object(Symfony\Component\DependencyInjection\Definition)) #2 /var/www/core/cms/vendor/symfony/symfony/src/Symfony/Component/DependencyInjection/Dumper/PhpDumper.php(117): Symfony\Componen in /var/www/core/cms/vendor/symfony/symfony/src/Symfony/Component/DependencyInjection/Dumper/PhpDumper.php on line 456
Services.yml
# This is the helper class for all entities
gutensite_cms.entity_helper:
class: Gutensite\CmsBundle\Service\EntityHelper
# This causes the Circular Reference Error when this service is included in Event Listener
arguments: [ "@doctrine.orm.cms_entity_manager" ]
# Passing via a setter injection also causes the same error.
#calls:
# - [setEntityManager, ['@doctrine.orm.cms_entity_manager']]
# An event listener for any entity that is Versionable
gutensite_cms.listener.is_versionable:
class: Gutensite\CmsBundle\EventListener\IsVersionableListener
#only pass in the services we need
arguments: [ "@gutensite_cms.entity_helper" ]
tags:
- { name: doctrine.event_listener, event: onFlush }
Gutensite\CmsBundle\Service\EntityHelper
namespace Gutensite\CmsBundle\Service;
use Doctrine\ORM\EntityManager;
class EntityHelper {
/**
* @var $em EntityManager
*/
private $em;
public function __construct(EntityManager $entityManager) {
$this->em = $entityManager;
}
/**
* Get the bundle shortcut path for an entity based on it's namespace.
*
* As an example, if your entity is Gutensite\CmsBundle\Entity\View\ViewVersion the function will return
* GutensiteCmsBundle:View\ViewVersion
*
* @param $entity
* @return string
*/
public function getEntityBundleShortcut($entity) {
// wrap get_class() in the entityManager metadata function to avoid returning cached proxy class
$path = explode('\Entity\\', $this->em->getClassMetadata(get_class($entity))->getName());
return str_replace('\\', '', $path[0]).':'.$path[1];
}
}
Gutensite\CmsBundle \EventListener\IsVersionableListener
namespace Gutensite\CmsBundle\EventListener;
use Doctrine\ORM\Event\OnFlushEventArgs;
use Gutensite\CmsBundle\Service\EntityHelper;
/**
* Class IsVersionableListener
* @package Gutensite\CmsBundle\EventListener
*/
class IsVersionableListener
{
/*
private $entityHelper;
public function __construct(EntityHelper $entityHelper) {
$this->entityHelper = $entityHelper;
}
*/
public function onFlush(OnFlushEventArgs $eventArgs)
{
// This never is excecuted because of the error
print('ON FLUSH EVENT EXECUTED');
exit;
$em = $eventArgs->getEntityManager();
$uow = $em->getUnitOfWork();
$updatedEntities = $uow->getScheduledEntityUpdates();
foreach($updatedEntities AS $entity) {
// This is generic listener for all entities that have an isVersionable method (e.g. ViewVersion)
// TODO: at the moment, we only want to do the following code for the viewVersion entity
if (method_exists($entity, 'isVersionable') && $entity->isVersionable()) {
// Get the Correct Repo for this entity
$entityShortcut = $this->entityHelper->getEntityBundleShortcut($entity);
$repo = $em->getRepository($entityShortcut);
// If the repo for this entity has an onFlush method, use it.
// This allows us to keep the functionality in the entity repo
if(method_exists($repo, 'onFlush')) {
$repo->onFlush($em, $entity);
}
}
}
}
}
推荐答案
对此的基本解决方案（如我所指出的）是删除 EntityManager 从服务定义（和服务类）。相反，您必须将 EntityManager 传递到需要它的函数中。这阻止了循环引用。
The basic solution to this (as I indicated) is to remove the construct or setter injection of the EntityManager from the service definition (and the service class). Instead you have to pass the EntityManager into the function that needs it. This prevents the circular reference.
我选择了这个，而不是创建一个 setEntityManager ，因为它似乎很笨重在EntityHelper服务上设置，然后调用该函数。似乎最好把它直接传递给需要它的功能。
I opted for this instead of a creating a setEntityManager because it seems clunky to have to set that on the EntityHelper service, before calling the function. It seems better to just pass it to the functions that need it directly.
Services.yml
Services.yml
# This is the helper class for all entities
gutensite_cms.entity_helper:
class: Gutensite\CmsBundle\Service\EntityHelper
# Do NOT pass in EntityManager via constructor or injector, because it causes a Circular Reference Error when this service is included in Event Listener
# An event listener for any entity that is Versionable
gutensite_cms.listener.is_versionable:
class: Gutensite\CmsBundle\EventListener\IsVersionableListener
#only pass in the services we need
arguments: [ "@gutensite_cms.entity_helper" ]
tags:
- { name: doctrine.event_listener, event: onFlush }
Gutensite\CmsBundle\Service\EntityHelper
Gutensite\CmsBundle\Service\EntityHelper
namespace Gutensite\CmsBundle\Service;
use Doctrine\ORM\EntityManager;
class EntityHelper {
/**
* Get the bundle shortcut path for an entity based on it's namespace.
*
* As an example, if your entity is Gutensite\CmsBundle\Entity\View\ViewVersion the function will return
* GutensiteCmsBundle:View\ViewVersion
*
* @param $entity
* @return string
*/
public function getEntityBundleShortcut(EventManager $eventManager, $entity) {
// wrap get_class() in the entityManager metadata function to avoid returning cached proxy class
$path = explode('\Entity\\', $eventManager->getClassMetadata(get_class($entity))->getName());
return str_replace('\\', '', $path[0]).':'.$path[1];
}
}
Gutensite\CmsBundle\EventListener \IsVersionableListener
Gutensite\CmsBundle\EventListener\IsVersionableListener
namespace Gutensite\CmsBundle\EventListener;
use Doctrine\ORM\Event\OnFlushEventArgs;
use Gutensite\CmsBundle\Service\EntityHelper;
/**
* Class IsVersionableListener
* @package Gutensite\CmsBundle\EventListener
*/
class IsVersionableListener
{
/*
private $entityHelper;
public function __construct(EntityHelper $entityHelper) {
$this->entityHelper = $entityHelper;
}
*/
public function onFlush(OnFlushEventArgs $eventArgs)
{
$em = $eventArgs->getEntityManager();
$uow = $em->getUnitOfWork();
$updatedEntities = $uow->getScheduledEntityUpdates();
foreach($updatedEntities AS $entity) {
// This is generic listener for all entities that have an isVersionable method (e.g. ViewVersion)
// TODO: at the moment, we only want to do the following code for the viewVersion entity
if (method_exists($entity, 'isVersionable') && $entity->isVersionable()) {
// Get the Correct Repo for this entity
$entityShortcut = $this->entityHelper->getEntityBundleShortcut($em, $entity);
$repo = $em->getRepository($entityShortcut);
// If the repo for this entity has an onFlush method, use it.
// This allows us to keep the functionality in the entity repo
if(method_exists($repo, 'onFlush')) {
$repo->onFlush($em, $entity);
}
}
}
}
}
这篇关于关于Flush事件听众服务原则的Symfony循环引用异常的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！