问题描述
我正在编写一个新的ZF2应用程序.我注意到ZF3不推荐使用从任何地方"调用服务的ServiceLocator使用模式.我想为ZF3编写代码.
I am writing a new ZF2 app. I have noticed that ServiceLocator usage pattern of calling services "from anywhere" has been deprecated from ZF3. I want to write code in mind for ZF3.
我能够设置我的Controller以便在构造函数时调用所有依赖项.但这意味着我需要先加载Doctrine对象.
I was able to set up my Controller to call all dependencies at constructor time. But that means loading i.e. Doctrine object upfront before I need it.
问题
如何设置它以便仅在需要时立即加载? (延迟加载).我了解到ZF3将加载工作转移到Controller构造上，这使得如何及时加载某些东西变得不明显.
How do I set it up so that it is only loaded when I need it immediately? (lazy-loaded). I understand that ZF3 moves loading to Controller construction, which makes it not apparent as to how to load something Just-In-Time.
旧代码
class CommissionRepository
{
protected $em;
function getRepository()
{
//Initialize Doctrine ONLY when getRepository is called
//it is not always called, and Doctrine is not always set up
if (! $this->em)
$this->em = $this->serviceLocator->get('doctrine');
return $this->em;
}
}
重构ServiceLocator模式后的当前代码
class CommissionRepository
{
protected $em;
function getRepository()
{
return $this->em;
}
function setRepository($em)
{
$this->em = $em;
}
function useRepository($id)
{
return $this->em->find($id);
}
}
class CommissionControllerFactory implements FactoryInterface
{
public function createService(ServiceLocatorInterface $serviceLocator)
{
$parentLocator = $controllerManager->getServiceLocator();
// set up repository
$repository = new CommissionRepository();
$repository->setRepository($parentLocator->get('doctrine'));
// set up controller
$controller = new CommissionController($repository);
$controller->setRepository();
return $controller;
}
}
class CommissionController extends AbstractActionController
{
protected $repository;
public function setRepository(CommissionRepository $repository)
{
$this->repository = $repository;
}
public function indexAction()
{
//$this->repository already contains Doctrine but it should not
//I want it to be initialized upon use. How?
//Recall that it has been set up during Repository construction time
//and I cannot call it from "anywhere" any more in ZF3
//is there a lazy loading solution to this?
$this->repository->useRepository();
}
推荐答案
如果您没有任何有效/强烈的理由来实例化自定义实体存储库，则您最好在存储库中扩展Doctrine\ORM\EntityRepository，例如CommissionRepository .例如；
If you don't have any valid/strong reason to instantiate a custom entity repository, you should prefer extending of Doctrine\ORM\EntityRepository in your repositories like CommissionRepository. For example;
use Doctrine\ORM\EntityRepository;
class CommissionRepository extends EntityRepository
{
// No need to think about $em here. It will be automatically
// injected by doctrine when you call getRepository().
//
function fetchCommissionById($id)
{
// You can easily get the object manager directly (_em) or
// using getEntityManager() accessor method in a repository
return $this->_em->find($id);
}
}
通过这种方式，当您调用$em->getRepository('App\Entity\Commission')方法时，实体管理器将自动注入到构建中的存储库中.
By this way, entity manager will be automatically injected to the repository on construction when you call the $em->getRepository('App\Entity\Commission') method.
<?php
namespace App\Entity;
use Doctrine\ORM\Mapping as ORM;
/**
* @ORM\Entity(repositoryClass="App\Repo\CommissionRepository")
* @ORM\Table
*/
class Commission
{
}
然后，您可以简化工厂中存储库的注入过程，例如:
Then you can simplify the injecting process of the repository in your factory something like:
// ZF2 Way
class CommissionControllerFactory implements FactoryInterface
{
public function createService(ServiceLocatorInterface $services)
{
$em = $services->getServiceLocator()->get('doctrine');
$repository = $em->getRepository('App\Entity\Commission');
return new CommissionController($repository);
}
}
// ZF3 Way
use Zend\ServiceManager\Factory\FactoryInterface;
use Interop\Container\ContainerInterface;
use Doctrine\ORM\EntityManager;
class CommissionControllerFactory implements FactoryInterface
{
public function __invoke(ContainerInterface $dic, $name, array $options = null) {
$em = $dic->get(EntityManager::class);
$repository = $em->getRepository('App\Entity\Commission');
return new CommissionController($repository);
}
}
这个问题；就像marcosh所说的那样， 懒惰服务 是在需要时立即创建服务的方法. ZF3发行时将使用zend-servicemanager 3.0组件. (当前zend-expressive使用它)自 servicemanager v3 您可以通过定义创建一些代理服务服务配置中的lazy_services 和代理人:
For the question; as of marcosh's said, Lazy Services are way to go to create services when need it immediately. ZF3 will use the zend-servicemanager 3.0 component when released. (Currently zend-expressive uses it) As of servicemanager v3 you can create some proxied services by defining lazy_services and delegators in your service configuration:
'factories' => [],
'invokables' => [],
'delegators' => [
FooService::class => [
FooServiceDelegatorFactory::class,
],
],
'lazy_services' => [
// map of service names and their relative class names - this
// is required since the service manager cannot know the
// class name of defined services up front
'class_map' => [
// 'foo' => 'MyApplication\Foo',
],
// directory where proxy classes will be written - default to system_get_tmp_dir()
'proxies_target_dir' => null,
// namespace of the generated proxies, default to "ProxyManagerGeneratedProxy"
'proxies_namespace' => null,
// whether the generated proxy classes should be written to disk or generated on-the-fly
'write_proxy_files' => false,
];
此外，从服务管理器v3开始工厂与 ContainerInterface 兼容.为了实现前向兼容性，您可能希望在工厂中同时保留__invoke()和createService()方法，以实现平稳迁移.
Also, starting with service manager v3 factories are compatible with the ContainerInterface. For the forward-compatibility, you may want to keep both __invoke() and createService() methods in your factories for a smooth migration.
最后，您的 ZF3兼容工厂可能看起来像:
In the end, your ZF3 compatible factory may look like:
class CommissionControllerFactory implements FactoryInterface
{
public function __invoke(ContainerInterface $container, $name, array $options = null)
{
$em = $container->get('doctrine');
$repository = $em->getRepository('App\Entity\Commission');
return new CommissionController($repository);
}
public function createService(ServiceLocatorInterface $container, $name = null, $requestedName = null)
{
return $this($container, $requestedName, []);
}
}
希望有帮助.
这篇关于如何使用ZF3设置延迟加载(任何地方都没有ServiceLocator模式)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！