Question

我在尝试实施MaintenanceListener服务时遇到了一些错误，该服务将显示维护页面这是我的服务。yml

# https://symfony.com/doc/current/service_container.html
services:
    # default configuration for services in *this* file
    _defaults:
        # automatically injects dependencies in your services
        autowire: true
        # automatically registers your services as commands, event subscribers, etc.
        autoconfigure: true
        # this means you cannot fetch services directly from the container via $container->get()
        # if you need to do this, you can override this setting on individual services
        public: false

    # makes classes in Cocorico\CoreBundle\DataFixtures\ORM\ available to be used as services
    # this creates a service per class whose id is the fully-qualified class name

#    Cocorico\CoreBundle\DataFixtures\ORM\:
#        resource: '../../src/Cocorico/CoreBundle/DataFixtures/ORM/*'


    # makes classes in src/AppBundle available to be used as services
    # this creates a service per class whose id is the fully-qualified class name
    AppBundle\:
        resource: '../../src/AppBundle/*'
        # you can exclude directories or files
        # but if a service is unused, it's removed anyway
        exclude: '../../src/AppBundle/{Entity,Repository,Tests,Event}'

    # controllers are imported separately to make sure they're public
    # and have a tag that allows actions to type-hint services
#    AppBundle\Controller\:
#        resource: '../../src/AppBundle/Controller'
#        public: true
#        tags: ['controller.service_arguments']

    # add more services, or override services that need manual wiring
    # AppBundle\Service\ExampleService:
    #     arguments:
    #         $someArgument: 'some_value'
    maintenance_listener:
        class: AppBundle\Event\MaintenanceListener
        arguments:
        tags:
            - { name: kernel.event_listener, event: kernel.request, method: onKernelRequest }```

这是我的课程：

<?php


namespace MListener;

use Symfony\Component\HttpKernel\Event\GetResponseEvent;
use Symfony\Component\HttpFoundation\Response;

class MListener
{
    public function onKernelRequest(GetResponseEvent $event)
    {
        $event->setResponse(new Response('Iziparty is in maintenance mode', Response::HTTP_SERVICE_UNAVAILABLE));
        $event->stopPropagation();
    }
}

这是我得到的错误： FastCGI在stderr中发送：“ PHP消息：PHP致命错误：无法声明类MListener \ MListener，因为该名称已在第9行的/var/www/Symfony/src/AppBundle/Event/MaintenanceListener.php中使用”来自上游的响应头感谢您的帮助。

Answer 1

全部归结为自动加载魔术。自动加载魔术假定具有某种目录结构，即（在其他方面）在composer.json中定义的目录结构。它基本上说：

命名空间AppBundle\...位于目录src/AppBundle/...

因此每个类AppBundle\Something\Else都位于src/AppBundle/Something/Else.php

现在，symfony开始加载应该处理事件的服务（由于您的配置）AppBundle\Event\MaintenanceListener，它将尝试实例化该事件，这会导致自动加载程序加载文件src/AppBundle/Event/MaintenanceListener.php其中仅包含类MListener/MListener。

由于自动加载有点麻烦，通常，它将尝试其他方法/定义，并可能尝试再次读取该文件，然后它将无法重新声明MListener/MListener类，因为它已经存在。

对此进行明确说明：如果遵循将目录结构绑定到名称空间结构的标准（在本例中为PSR-4），则这些方法将非常有效。如果您在文件中放入某些内容，根据PSR-4的说法，该内容不属于该文件，那么您将遇到麻烦，就像您遇到的那样。

修复很容易而且很明显：名称空间是目录（使用反斜杠而不是操作系统具有的任何目录分隔符），文件名是类名（显然没有.php）。因此，要么将文件重命名为src/MListener/MListener.php并相应地修改services.yaml：MListener\Mlistener: ...，要么将文件中的名称空间和类分别重命名为AppBundle\Event和MaintenanceListener。 / p>

Answer 2

请确保创建文件src / Event / MaintenanceListener.php

<?php

namespace AppBundle\Event;

use Symfony\Component\HttpKernel\Event\GetResponseEvent;
use Symfony\Component\HttpFoundation\Response;

class MaintenanceListener
{
    public function onKernelRequest(GetResponseEvent $event)
    {
        $event->setResponse(new Response('Iziparty is in maintenance mode', Response::HTTP_SERVICE_UNAVAILABLE));
        $event->stopPropagation();
    }
}

在文件service.yaml中声明了相同的名称

无法声明类symfony 3

2 个答案: