EventsController.php

<?php

namespace Bundle\FrontendBundle\Controller;

use Symfony\Component\HttpFoundation\Response;
use Symfony\Bundle\FrameworkBundle\Controller\Controller;
use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;
use Sensio\Bundle\FrameworkExtraBundle\Configuration\ParamConverter;

class EventsController extends Controller
{
    /**
     *
     * @Route(
     *     "/events",
     *     name="events_index"
     * )
     * @ParamConverter(
     *     name="limit",
     *     converter="QueryString"
     * )
     * @ParamConverter(
     *     name="accessToken",
     *     options={"field"="X-Facebook-AccessToken"},
     *     converter="HeaderField"
     * )
     */
    public function indexAction(string $accessToken = null, int $limit = 100): Response
    {
        if (!$accessToken || empty($accessToken)) {
            return $this->json(null, Response::HTTP_UNAUTHORIZED);
        }

        // ...

        return $this->json($response);
    }
}

HeaderFieldConverter.php

<?php
namespace Bundle\FrontendBundle\Request\ParamConverter;

use \Sensio\Bundle\FrameworkExtraBundle\Configuration\ParamConverter;
use \Sensio\Bundle\FrameworkExtraBundle\Request\ParamConverter\ParamConverterInterface;
use \Symfony\Component\HttpFoundation\Request;


class HeaderFieldConverter implements ParamConverterInterface
{
    /**
     * @param ParamConverter $configuration
     *
     * @return bool
     */
    public function supports(ParamConverter $configuration)
    {
        return $configuration->getConverter() === 'HeaderField';
    }

    public function apply(Request $request, ParamConverter $configuration)
    {
        $options = $configuration->getOptions();
        $target = $configuration->getName();
        $source = isset($options['field']) ? $options['field'] : $target;

        if (!$request->headers->has($source)) {
            return false;
        }

        $value = $request->headers->get($source);
        $request->attributes->set($target, $value);
    }
}

QueryStringConveter.php

<?php
namespace Bundle\FrontendBundle\Request\ParamConverter;

use \Sensio\Bundle\FrameworkExtraBundle\Configuration\ParamConverter;
use \Sensio\Bundle\FrameworkExtraBundle\Request\ParamConverter\ParamConverterInterface;
use \Symfony\Component\HttpFoundation\Request;


class QueryStringConverter implements ParamConverterInterface
{
    /**
     * @param ParamConverter $configuration
     *
     * @return bool
     */
    public function supports(ParamConverter $configuration)
    {
        return $configuration->getConverter() === 'QueryString';
    }

    public function apply(Request $request, ParamConverter $configuration)
    {
        $source = $configuration->getName();
        $target = $source;

        if (!$request->query->has($source)) {
            return false;
        }

        $value = $request->query->get($source);
        $request->attributes->set($target, $value);
    }
}

services.yml

services:
  # Query parameter converter
  request.paramconverter.querystring:
    class:  Bundle\FrontendBundle\Request\ParamConverter\QueryStringConverter
    tags:
      - { name: request.param_converter, converter: QueryString }
  # Header field converter
  request.paramconverter.header:
    class:  Bundle\FrontendBundle\Request\ParamConverter\HeaderFieldConverter
    tags:
      - { name: request.param_converter, converter: HeaderField }