Symfony 2.8 injecting twig

4
votes

Pre-note: I am learning Symfony from a Drupal 7 background.

I have created a custom model (although I think they are called services in Symfony from what I have read), and would like it to render an array via twig into a variable.

I found this link, and thought that this injection approach would do the trick: http://symfony.com/doc/2.8/service_container.html

Sadly, I and up with the below error:

Type error: Argument 1 passed to AppBundle\Model\Newsletter::__construct() must be an instance of AppBundle\Model\Twig_Environment, none given, called in /home/dan/working_files/symfony-playground/src/AppBundle/Controller/DefaultController.php on line 130

So, I am wondering what is an acceptable approach so I can use twig within my custom model/service/class?

If it is of use, here is some of my code for reference:

services.yml

services:
    appbundle.newsletter:
        class: AppBundle\Model\Newsletter
        arguments: ['@twig']

src/AppBundle/Model/Newsletter.php

namespace AppBundle\Model;

class Newsletter
{
    private $twig;
    public function __construct(Twig_Environment $twig)
    {
        $this->twig = $twig;
    }
}

Calling my model

$newsletter = new Newsletter();
2
phpsymfonydependency-injectionmodel
you should call your model as service to inject dependencies, if you calling it in controller you can get service like this $newsletter = $this->get('appbundle.newsletter'); – ArtOsi
Sorry, I am not sure what you mean. The line $newsletter = new Newsletter(); is being called from DefaultController.php at the moment. – retrodans
so controller has helper to get services. Simple calling $this->get('service_name'); will get you service with dependencies injected. If you calling class with new ClassName() then you have to manually pass twig instance to class constructor. – ArtOsi
Ah fantastic, a mixture of this and the comment from Alessandro have together helped to resolve this, thanks for the help. – retrodans

2 Answers

2
votes

try to change twig with EngineInterface like this:

services:
    appbundle.newsletter:
        class: AppBundle\Model\Newsletter
        arguments: ['@templating']

And

namespace AppBundle\Model;

use Symfony\Bundle\FrameworkBundle\Templating\EngineInterface;

class Newsletter
{
    private $twig;
    public function __construct(EngineInterface $templating)
    {
        $this->twig = $templating;
    }
}

After you need o call the service:

$this->get('service_name');
0
votes

When you call $newsletter = new Newsletter(); you're not accessing the service through the dependency injection container, ignoring the service definition you did.

To leverage the DIC and have your dependencies like @twig injected on your service, you should grab the service instance using the service container. To do that on a Symfony controller you can do it like this:

$newsletter = $this->get('appbundle.newsletter');

@twig is gonna be injected in your service as defined on the yaml file and it is shared between every place you use your service again through the container.