gistfile1.php

<?php

require_once 'vendor/autoload.php';

$routes = new \Symfony\Component\Routing\RouteCollection();
$routes->add('negotiation', new \Symfony\Component\Routing\Route(
    '/negotiation.{_locale}.{_format}',
    array(),
    array('_locale' => 'fr|en|es', '_format' => 'html|xml'),
    array('negotiate' => array('_locale', '_format'))
));

$request = \Symfony\Component\HttpFoundation\Request::create('/negotiation');
$request->headers->set('Accept', 'text/html, text/xml;q=0.9');
$request->headers->set('Accept-Language', 'fr, en;q=0.9');

$context = new \Symfony\Component\Routing\RequestContext();
$context->fromRequest($request);

$router = new \Symfony\Component\Routing\Matcher\UrlMatcher($routes, $context);
$parameters = $router->match('/negotiation');

var_dump($parameters);

// array(4) {
//   ["_locale"]=>
//   string(2) "fr"
//   ["_format"]=>
//   string(4) "html"
//   ["_charset"]=>
//   NULL
//   ["_route"]=>
//   string(11) "negotiation"
// }