如果我没有/无法使用 DI 注入服务，我如何直接从容器中获取服务?

2021-12-26 00:00:00 dependency-injection php symfony symfony4 service-locator

我有一部分代码，我通过依赖注入注入了两个服务 $checker 和 $paginator.它完美地工作:

I have a part of code where I'm injecting two services $checker and $paginator by dependency injection. It works perfectly:

public function index(Request $request, Paginator $paginator, Checker $checker)
    {
        $result = ['a', 'b', 'c', 'd', 'e', 'f', 'g'];
        $partialResult = $paginator->getPartial($result, 0, 3);
        $checker->isValid('A');
        var_dump("test");
        die;
    }

在services.yaml文件的配置下面:

   paginator:
        public: true
        class: 'AppHelperPaginator'

    checker:
        public: true
        class: 'AppHelperChecker'
        arguments:
         $paginator: '@paginator'

但由于某些原因我想通过方法注入服务:

But I'd like to inject for some reasons service by method:

$checker = $this->container->get('checker');

但它不起作用.在以前的 Symfony 版本中，像 3.4 那样.

But it doesn't work. In previous versions Symfony like 3.4 it used to.

我收到一个错误:

未找到服务checker":事件虽然它存在于应用程序的容器中，但AppControllerDefaultController"中的容器是一个较小的服务定位器，它只知道http_kernel"、parameter_bag"、request_stack"、路由器"、会话"和树枝"服务.尝试改用依赖注入.

Service "checker" not found: event though it exists in the app's container, the container inside "AppControllerDefaultController" is a smaller service locator that only knows about the "http_kernel", "parameter_bag", "request_stack", "router", "session", and "twig" services. Try using dependency injection instead.

我该如何解决这个问题?

How should I solve this?

推荐答案

你需要添加你的依赖项 服务定位器可以找到它们.

You need to add your dependencies so the service locator can find them.

将方法 getSubscribedServices() 添加到您的控制器类:

Add a method getSubscribedServices() to your controller class:

public static function getSubscribedServices()
{
    return array_merge(
        parent::getSubscribedServices(),
        [
            'checker' => Checker::class,
        ]
    );
}

如果你的控制器类扩展了 AbstractController 你可以简单地做:

If your controller class extends AbstractController you can simply do:

$this->get('checker');

如果您想在其他类型的类中执行此操作(例如不扩展AbstractController 的服务)，那么您需要声明您的服务实现了ServiceSubscriberInterface.

If you want to do it in another type of class (e.g. a service that doesn't extend AbstractController), then you need to declare that your service implements the ServiceSubscriberInterface.

use SymfonyContractsServiceServiceSubscriberInterface;
use PsrContainerContainerInterface;

class FooService implements ServiceSubscriberInterface {

    public function __construct(ContainerInterface $locator)
    {
        $this->locator = $locator;
    }

    public static function getSubscribedServices() { /* same as before */ }

    public function get($service)
    {
        return $this->locator->get($service);
    }
}

...并且您可以像之前在控制器中那样做同样的事情.

... and you would be able to do the same than you in the controller earlier.

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