在Symfony2中使用树枝扩展的助手服务

Question

我试图设置一个细枝过滤器，其工作方式如下：{{entities | fieldnames}}，该过滤器将返回一个包含实体对象的属性名称的数组。我的问题是，经过几个小时的阅读和尝试，我无法执行$this-

错误：对/Users/a77/Dropbox/06中的非对象调用成员函数get（）。Proyectos/2011 U-Vox/DEV U-Vox/Uvox Web/src/Acme/DemoBundle/Extension/FieldnamesTwigExtension。php第38行

或者如果构造不带=null Error ContextErrorException:Catchable致命错误：传递给Acme\DemoBundle\Extension\FieldnamesTwigExtension:：\uuu construct（）的参数1必须是Acme\DemoBundle\Extension\Container的实例，没有给定，在

服务。yml

服务：

helpers:
    class:        Acme\DemoBundle\Services\Helpers

twig.extension.acme.demo:
    class:        Acme\DemoBundle\Twig\Extension\DemoExtension
    arguments:    [twig.loader]

acme.demo.listener:
    class:        Acme\DemoBundle\EventListener\ControllerListener
    arguments:    [twig.extension.acme.demo]

fieldnames:
    class: Acme\DemoBundle\Extension\FieldnamesTwigExtension
    arguments:  [@service_container]

Extension\FieldnamesTwigExtension。php

use Symfony\Component\DependencyInjection\ContainerInterface as Container;
namespace Acme\DemoBundle\Extension;

class FieldnamesTwigExtension extends \Twig_Extension {
private $container;
public function __construct(Container $container=null)
{
    $this->container = $container;
    //var_dump ($container); exit; //  prints null !!!

}
 protected function get($service)
{
    return $this->container->get($service);
}

public function getFilters() {
    return array(
        'fieldnames' => new \Twig_Filter_Method($this, 'fieldnamesFilter'),
    );
}

public function getName() {
    return 'fieldnames_twig_extension';
}

public function fieldnamesFilter($obj) {
    if (is_array($obj)) {
        $first = $obj[0];

// GET (HELPERS) NOT WORKING :

       $fieldnames = $this->container->get("helpers")->getFieldnames($first);
        return $fieldnames;
    }
    return null;
}

public function twig_array_get_function($array, $name) {
    return $array[$name];
}

}

帮手。php

namespace Acme\DemoBundle\Services;

class Helpers {

public function sum($n1, $n2) {
    return $n1 + $n2;
}

public function getFieldnames($entities) {
    $reflect = new \ReflectionClass($entities[0]);
    $props = $reflect->getProperties();
    $fieldnames = Array();
    foreach ($props as $prop) {
        $fieldnames[] = $prop->getName();
    }
    return $fieldnames;
 }

}

AcmeDemoExtension.php

名称空间Acme\DemoBundle\DependencyInjection；

使用Symfony\Component\DependencyInjection\ContainerBuilder；使用Symfony\Component\DependencyInjection\Loader\YamlFileLoader；使用Symfony\Component\HttpKernel\DependencyInjection\Extension；使用Symfony\Component\Config\FileLocator；使用Symfony\Component\DependencyInjection\Definition；//补充

类AcmeDemoExtension扩展了{

public function load(array $configs, ContainerBuilder $container) {

    $definition = new Definition('Acme\DemoBundle\Extension\AccessTwigExtension');
    $definition->addTag('twig.extension');
    $container->setDefinition('access_twig_extension', $definition);

    $definition2 = new Definition('Acme\DemoBundle\Extension\FieldnamesTwigExtension');
    $definition2->addTag('twig.extension');
    $container->setDefinition('fieldnames_twig_extension', $definition2);


    $loader = new YamlFileLoader($container, new FileLocator(__DIR__ . '/../Resources/config'));
    $loader->load('services.yml');
}

public function getAlias() {
    return 'acme_demo';
}

 }

Answer 1

在扩展\FieldnamesTwigExtension.php中，在use指令之后调用命名空间是否正常？

返回哪个错误Symfony？

Answer 2

你太难了。您应该将助手直接注入到您的小树枝扩展中。您还应该在服务中进行标记。yml。不在依赖项注入扩展中。

http://symfony.com/doc/current/cookbook/templating/twig_extension.html

服务。yml

fieldnames:
    class: Acme\DemoBundle\Extension\FieldnamesTwigExtension
    arguments:  [@helpers]
    tags:
        - { name: twig.extension }

并相应地调整代码的其余部分。

Answer 3

我在我的应用程序上尝试了你的代码，但出现了相同的错误。要解决这个问题：

Acme\DemoBundle\DependencyInjection\AcmeDemoExtension。php

删除以下行：

$definition2 = new Definition('Acme\DemoBundle\Extension\FieldnamesTwigExtension');
$definition2->addTag('twig.extension');
$container->setDefinition('fieldnames_twig_extension', $definition2);

Acme\DemoBundle\Resources\config\services.yml

替换以下行：

fieldnames:
    class: Acme\DemoBundle\Extension\FieldnamesTwigExtension
    arguments:  [@service_container]

作者：

fieldnames:
    class: Acme\DemoBundle\Extension\FieldnamesTwigExtension
    arguments:  [@service_container]
    tags: [{ name: twig.extension }]