Doctrine onFlush 事件侦听器服务的 Symfony 循环引用异常-php问题

Symfony Circular Reference Exception for Doctrine onFlush Event Listener Service(Doctrine onFlush 事件侦听器服务的 Symfony 循环引用异常)

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问题描述

我为 Doctrine onFlush 事件监听器创建了一个服务.在这个监听器中，我想引用我在另一个服务中的一个通用函数来检查实体的快捷路径.该 other 服务使用实体管理器来执行此操作，因此该 other 服务的服务定义将原则实体管理器作为构造函数参数注入.但是，如果我在主 onFlush 事件侦听器中包含该other 服务，则会收到关于循环引用的严重错误.

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.

我可以让这个 entity_helper 服务在集合函数 setEntityManager($entityManager) 中接受实体管理器.但这意味着每当我在其他任何地方使用此 entity_helper 服务时，我都必须始终传入 EntityManager.也许没关系，但这是唯一的解决方案吗?一开始我的逻辑/理解有问题吗?(我是 Symfony 的新手，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).

附件 A:严重错误

Fatal error: Uncaught exception 'SymfonyComponentDependencyInjectionExceptionServiceCircularReferenceException' 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): SymfonyComponentDependencyInjectionDumperPhpDumper->addServiceInlinedDefinitionsSetup('doctrine.dbal.c...', Object(SymfonyComponentDependencyInjectionDefinition)) #1 /var/www/core/cms/vendor/symfony/symfony/src/Symfony/Component/DependencyInjection/Dumper/PhpDumper.php(630): SymfonyComponentDependencyInjectionDumperPhpDumper->addService('doctrine.dbal.c...', Object(SymfonyComponentDependencyInjectionDefinition)) #2 /var/www/core/cms/vendor/symfony/symfony/src/Symfony/Component/DependencyInjection/Dumper/PhpDumper.php(117): SymfonyComponen 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: GutensiteCmsBundleServiceEntityHelper
    # 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: GutensiteCmsBundleEventListenerIsVersionableListener
    #only pass in the services we need
    arguments: [ "@gutensite_cms.entity_helper" ]
    tags:
        - { name: doctrine.event_listener, event: onFlush }

GutensiteCmsBundleServiceEntityHelper

namespace GutensiteCmsBundleService;

use DoctrineORMEntityManager;

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 GutensiteCmsBundleEntityViewViewVersion the function will return
     * GutensiteCmsBundle:ViewViewVersion
     *
     * @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];
    }

}

GutensiteCmsBundleEventListenerIsVersionableListener

namespace GutensiteCmsBundleEventListener;

use DoctrineORMEventOnFlushEventArgs;
use GutensiteCmsBundleServiceEntityHelper;


/**
 * Class IsVersionableListener
 * @package GutensiteCmsBundleEventListener
 */
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(正如我所指出的)是从服务定义中移除 EntityManager 的构造或设置注入(和服务类).相反，您必须将 EntityManager 传递给需要它的函数.这可以防止循环引用.

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 因为在调用函数之前必须在 EntityHelper 服务上设置它似乎很笨拙.直接把它传递给需要它的函数似乎更好.

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.

服务.yml

# This is the helper class for all entities
gutensite_cms.entity_helper:
    class: GutensiteCmsBundleServiceEntityHelper
    # 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: GutensiteCmsBundleEventListenerIsVersionableListener
    #only pass in the services we need
    arguments: [ "@gutensite_cms.entity_helper" ]
    tags:
        - { name: doctrine.event_listener, event: onFlush }

GutensiteCmsBundleServiceEntityHelper

namespace GutensiteCmsBundleService;

use DoctrineORMEntityManager;

class EntityHelper {


    /**
     * Get the bundle shortcut path for an entity based on it's namespace.
     *
     * As an example, if your entity is GutensiteCmsBundleEntityViewViewVersion the function will return
     * GutensiteCmsBundle:ViewViewVersion
     *
     * @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];
    }

}

GutensiteCmsBundleEventListenerIsVersionableListener

namespace GutensiteCmsBundleEventListener;

use DoctrineORMEventOnFlushEventArgs;
use GutensiteCmsBundleServiceEntityHelper;


/**
 * Class IsVersionableListener
 * @package GutensiteCmsBundleEventListener
 */
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);
                }

            }
        }
    }
}

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