Question

我在Zend项目中使用了Doctrine 2 ORM，并且需要在几种情况下将我的实体序列化为JSON。

ATM我使用Querybuilder并加入我需要的所有表。但是我的序列化程序导致学说延迟加载每个相关的实体，导致相当大的数据量并引发递归。

现在我正在寻找一种完全禁用Doctrines延迟加载行为的方法。

我选择数据的方法如下：

$qb= $this->_em->createQueryBuilder()
            ->from("\Project\Entity\Personappointment", 'pa')
            ->select('pa', 't', 'c', 'a', 'aps', 'apt', 'p')
            ->leftjoin('pa.table', 't')
            ->leftjoin('pa.company', 'c')
            ->leftjoin('pa.appointment', 'a')
            ->leftjoin('a.appointmentstatus', 'aps')
            ->leftjoin('a.appointmenttype', 'apt')
            ->leftjoin('a.person','p')

我希望我的结果集只包含选定的表和关联。

非常感谢任何帮助。

Answer 1

在最新版本的JMSSerializer中，你应该看看的地方是

JMS\Serializer\EventDispatcher\Subscriber\DoctrineProxySubscriber

而不是

Serializer\Handler\DoctrineProxyHandler

要覆盖默认的延迟加载行为，应该定义自己的事件订阅者。

在app/config.yml添加此内容：

parameters:
    ...
    jms_serializer.doctrine_proxy_subscriber.class: Your\Bundle\Event\DoctrineProxySubscriber

您可以将类从JMS \ Serializer \ EventDispatcher \ Subscriber \ DoctrineProxySubscriber复制到您的\ Bundle \ Event \ DoctrineProxySubscriber并注释掉$ object-＆gt; __ load（）;线

public function onPreSerialize(PreSerializeEvent $event)
{
    $object = $event->getObject();
    $type = $event->getType();

    // If the set type name is not an actual class, but a faked type for which a custom handler exists, we do not
    // modify it with this subscriber. Also, we forgo autoloading here as an instance of this type is already created,
    // so it must be loaded if its a real class.
    $virtualType = ! class_exists($type['name'], false);

    if ($object instanceof PersistentCollection) {
        if ( ! $virtualType) {
            $event->setType('ArrayCollection');
        }

        return;
    }

    if ( ! $object instanceof Proxy && ! $object instanceof ORMProxy) {
        return;
    }

     //$object->__load(); Just comment this out

    if ( ! $virtualType) {
        $event->setType(get_parent_class($object));
    }
}

Answer 2

在Doctrine中寻找答案后，我的团队发现JMS Serializer是“问题”。它自动触发了Doctrine Proxies的使用。我们编写了一个Patch for JMS Serializer以避免延迟加载。

我们实现了自己的 DoctrineProxyHandler ，它不会触发Doctrines延迟加载机制并在我们的SerializationHandlers数组中注册它。

class DoctrineProxyHandler implements SerializationHandlerInterface {

public function serialize(VisitorInterface $visitor, $data, $type, &$handled)
{
    if (($data instanceof Proxy || $data instanceof ORMProxy) && (!$data->__isInitialized__ || get_class($data) === $type)) {
        $handled = true;

        if (!$data->__isInitialized__) {

            //don't trigger doctrine lazy loading
            //$data->__load();

            return null;
        }

        $navigator = $visitor->getNavigator();
        $navigator->detachObject($data);

        // pass the parent class not to load the metadata for the proxy class
        return $navigator->accept($data, get_parent_class($data), $visitor);
    }

    return null;
}

现在我可以简单地选择我的表，加入我需要的关联 - 我的JSON将只包含我选择的数据而不是无限深度关联和递归：）

$qb= $this->_em->createQueryBuilder()
        ->from("\Project\Entity\Personappointment", 'pa')
        ->select('pa', 't', 'c', 'a')
        ->leftjoin('pa.table', 't')
        ->leftjoin('pa.company', 'c')
        ->leftjoin('pa.appointment', 'a')

JSON将只包含

{  
  Personappointment: { table {fields}, company {fields}, appointment {fields}}
  Personappointment: { table {fields}, company {fields}, appointment {fields}}
  Personappointment: { table {fields}, company {fields}, appointment {fields}}
  .
  .
}

Answer 3

这可能被称为丑陋的拐杖，但您可以只选择（）您真正需要的数据，然后使用Query对象的getArrayResult（）方法将结果水合成数组...

Answer 4

使用Doctrine的查询构建器时，您无法禁用链接模型类的延迟加载。如果您想绕过这种行为，最好不得不使用Doctrine的DBAL请求数据。

不要使用\Doctrine\ORM\QueryBuilder但\Doctrine\DBAL\Query\QueryBuilder。

$qb = new QueryBuilder($this->_em->getConnection());
$expr = $qb->expr();

$qb->select('pa.*', 't.*', 'c.*', 'a.*', 'aps.*', 'apt.*', 'p.*')
   ->from('person_appointment', 'pa')
   ->leftJoin('pa', 'table', 't', $expr->eq('pa.table_id', 't.table_id'))
   // put other joints here
   // ...
   ->leftjoin('a', 'person', 'p', $expr->eq('a.person_id', 'p.person_id'));

Answer 5

您希望实际使用您的或默认订阅者

的情况

@DavidLin回答：

您可以将类从JMS \ Serializer \ EventDispatcher \ Subscriber \ DoctrineProxySubscriber复制到您的\ Bundle \ Event \ DoctrineProxySubscriber并注释掉$ object-＆gt; __ load（）;线

<?php

/*
 * Copyright 2013 Johannes M. Schmitt <schmittjoh@gmail.com>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

namespace Your\Bundle\Event;

use Doctrine\ORM\PersistentCollection;
use Doctrine\ODM\MongoDB\PersistentCollection as MongoDBPersistentCollection;
use Doctrine\ODM\PHPCR\PersistentCollection as PHPCRPersistentCollection;
use Doctrine\Common\Persistence\Proxy;
use Doctrine\ORM\Proxy\Proxy as ORMProxy;
use JMS\Serializer\EventDispatcher\PreSerializeEvent;
use JMS\Serializer\EventDispatcher\EventSubscriberInterface;

class AvoidDoctrineProxySubscriber implements EventSubscriberInterface
{
    public function onPreSerialize(PreSerializeEvent $event)
    {
        $object = $event->getObject();
        $type = $event->getType();

        // If the set type name is not an actual class, but a faked type for which a custom handler exists, we do not
        // modify it with this subscriber. Also, we forgo autoloading here as an instance of this type is already created,
        // so it must be loaded if its a real class.
        $virtualType = ! class_exists($type['name'], false);

        if ($object instanceof PersistentCollection
            || $object instanceof MongoDBPersistentCollection
            || $object instanceof PHPCRPersistentCollection
        ) {
            if ( ! $virtualType) {
                $event->setType('ArrayCollection');
            }

            return;
        }

        if ( ! $object instanceof Proxy && ! $object instanceof ORMProxy) {
            return;
        }


        //Avoiding doctrine lazy load proxyes
        //$object->__load();

        if ( ! $virtualType) {
            $event->setType(get_parent_class($object));
        }
    }

    public static function getSubscribedEvents()
    {
        return array(
            array('event' => 'serializer.pre_serialize', 'method' => 'onPreSerialize'),
        );
    }
}

并像这样初始化序列化：

$serializer = JMS\Serializer\SerializerBuilder::create()
    //remove this to use lazy loading 
    ->configureListeners(function(JMS\Serializer\EventDispatcher\EventDispatcher $dispatcher) {
        $dispatcher->addSubscriber(new Your\Bundle\Event\AvoidDoctrineProxySubscriber());
    })  
    // !remove this to use lazy loading 
    ->build();

//and serialize the data with/without Lazy

serializer->serialize($data, 'json');

使用JMS Serializer时禁用Doctrine 2延迟加载？

5 个答案: