Symfony2 POST路由在Facebook iFrame中返回404

I have a route that looks like this:

SiteGameBundle_GameFinish:
    pattern:  /game/finish
    defaults: { _controller: SiteGameBundle:Game:finish }
    requirements:
        _method:  POST

If I manually make a POST request with curl, the page successfully returns the correct path.

However, if I attempt to call the URL with AJAX it returns 404 every time. When I inspect the request data, the URL and the request method are all set appropriately. I can't figure out what would cause Symfony2 to return a 404 error in this instance.

This had nothing to do with being AJAX or non-AJAX.

Apparently adding a trailing slash to the route creates a 404 error.