CORS Api with symfony

I'm not sure that's the right way, but I resolved for me:

1. Create new event subscriber (like ResponseSubscriber)
2. Listen KernelEvents::RESPONSE event
3. In your handler add the following:

if ($event->getRequest()->getMethod() === 'OPTIONS') {
    $event->setResponse(
            new Response('', 204, [
                'Access-Control-Allow-Origin' => '*',
                'Access-Control-Allow-Credentials' => 'true',
                'Access-Control-Allow-Methods' => 'GET, POST, PUT, DELETE, OPTIONS',
                'Access-Control-Allow-Headers' => 'DNT, X-User-Token, Keep-Alive, User-Agent, X-Requested-With, If-Modified-Since, Cache-Control, Content-Type',
                'Access-Control-Max-Age' => 1728000,
                'Content-Type' => 'text/plain charset=UTF-8',
                'Content-Length' => 0
            ])
        );
    return ;
}

I advise you to use NelmioCorsBundle:

https://github.com/nelmio/NelmioCorsBundle

This bundle allows you to send Cross-Origin Resource Sharing headers with ACL-style per-URL configuration.

Is very useful for CORS problem