Silverstripe扩展控制器操作

I'm trying to add a Controller Action to the Page_Controller class via an extension.

The desired result is to be able to go to www.mysite.com/setlanguage/spanish for instance and have that update the site's language to spanish via a browser cookie.

However I'm failry new to Extensions in SilverStripe and so far when I visit the link to the controller action all I get is a 404 error.

Please take a look at my code...

class Page_ControllerLanguageExtension extends Extension {

    private static $allowed_actions = array(
        'setLanguage'
    );

    public function setLanguage(SS_HTTPRequest $request) {

        $requestedLanguage = $request->param('ID');
        $languageCookie = new Cookie;
        $languageCookie->set('site_language', $requestedLanguage);

        return $this->owner->RedirectBack();

    }
}

And I'm calling in the extension with a YML config file:

Page_Controller:
  extensions:
    - Page_ControllerLanguageExtension

Thanks in advance.

So if you need /setlanguage/<language> as the url you have to route the url /setlanguage/ to a seperate controller:

class SetLanguageController extends Controller {

    public function index(SS_HTTPRequest $request) {

        $requestedLanguage = $request->param('Language'); //as defined in config below
        $languageCookie = new Cookie;
        $languageCookie->set('site_language', $requestedLanguage);

        return $this->RedirectBack();

    }
}

We don't need to define $allowed_actions in this case, cause action index is allowed by default.

Now in your /mysite/_config/routes.yml you have to define the route to your controller:

---
Name: mysite-routes
After: framework/routes#coreroutes
---

Director:
  rules:
    'setlanguage/$Language': 'SetLanguageController'