How to register twig filter into Symfony 4?

Question

I have a problem of registration with my custom twig extension in Symfony 4 . I have create extension who help me to decode my json data but it's not work. This message is display when I want to use my json_decode filter. Error message

The code of my custom twig filter :

<?php
namespace App\Twig;

use Twig\Extension\AbstractExtension;
use Twig\TwigFilter;

class AppExtension extends AbstractExtension
{
    public function getName() {
        return 'Json Decode';
    }

    public function getFunctions()
    {
        return [
            new TwigFilter('json_decode', [$this, 'json_decode']),
        ];
    }

    public function json_decode($input, $assoc = false) {
       return json_decode($input,$assoc);
    }
}
?>

Here is a twig_exension.yaml

services:
    _defaults:
        public: false
        autowire: true
        autoconfigure: true

    # Uncomment any lines below to activate that Twig extension
    #Twig\Extensions\ArrayExtension: null
    #Twig\Extensions\DateExtension: null
    Twig\Extensions\IntlExtension: null
    Twig\Extensions\TextExtension: null
    App\Twig\AppExtension: null

Here is the line that return and error in my twig file

{% set commande = render(controller('App\\Controller\\StoreController::getProduitsCommandes')) | json_decode  %}

Here is the Response return in StoreController.php

$response = new Response(json_encode(["produits"=>$produitsArray,"total_ht"=>$total_ht,"tva"=>$tva,"nbre_produits"=>$nbre_produits]));
$response->headers->set('Content-Type', 'application/json');
return $response;

When I type php bin/console debug:twig --filter=json_decode The debugger return me this result

---------

* json_decode(input, assoc = false)

Thank you for your attention If any people has a solution it will help me

Answer 1

As the errors states the filter can not be found. This is due to the fact you are trying to register your filter as a function, move the registration to the getFilters method instead. Also it's perfectly viable to chain existing functions

<?php
namespace App\Twig;

use Twig\Extension\AbstractExtension;
use Twig\TwigFilter;

class AppExtension extends AbstractExtension
{
    public function getFilters()
    {
        return [
            new TwigFilter('json_decode', 'json_decode'), //just chain to existing PHP function
        ];
    }
}

---

sidenote The method getName is now obsolete and can be removed as it has been deprecated and isn't used anymore in the code

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