Symfony / Twig：在Twig模板中打印函数返回

Question

I'd like to do something like :

{{ users_number() }} or {{ users_number }}

in a Twig's template. My service looks like this :

class HomeExtension extends \Twig_Extension
 {
   public function getFunction()
    {
        return array(
            new \Twig_SimpleFunction('users_number', array($this, 'getUsersNb'))
        );
    }

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

    public function getUsersNb(){
        $em = $this->getDoctrine()->getManager();
        $countUsers = $em->getRepository("ASDPUsersBundle:Users")->getNb();
        return $countUsers;
    }
}

Still, i can't get my value in my view. How could i do it ? Or did i miss something in my service ?

Edit: I registered my service like this :

services:
 users_number:
  class: ASDP\HomeBundle\Twig\Extension\HomeExtension
  tags:
   - { name : twig.extension }

Is it the right way ?

Answer 1

Try this:

public function getFunctions()
{
    return array(
        new \Twig_SimpleFunction('users_number', array($this,'getUsersNb')))
    );
}

And your extension must extend \\Twig_Extension and service must have tag twig.extension :

<service class="Vendor\Bundle\Twig\Extension\YourExtension" id="your.extension.id">
  <tag name="twig.extension"/>
</service> 

OR in Yaml:

your.extension.id:
    class: Vendor\Bundle\Twig\Extension\YourExtension
    tags:
        - { name: twig.extension }

Answer 2

You need to inject the entity manager on your Twig Extension Service

your.extension.id:
    class: Vendor\Bundle\Twig\Extension\YourExtension
    arguments: ["@doctrine.orm.entity_manager"]
    tags:
        - { name: twig.extension }

And then use it in your custom extension:

protected $em;

public function __construct($em)
{
    $this->translator = $translator;
}

// ...

public function getUsersNb()
{
    $countUsers = $this->em->getRepository("ASDPUsersBundle:Users")->getNb();
    return $countUsers;
}

I hope it helps.