如何使用Facebook PHP SDK v4请求画布应用程序的权限

I'm wondering how to correctly ask for permissions (publish_actions), with a canvas application using the Facebook PHP SDK v4.

Asking for permission is the same as other apps:

// set redirect_uri
$helper = new FacebookRedirectLoginHelper( 'http://apps.facebook.com/yourapp' );

// login link
echo '<a href="' . $helper->getLoginUrl( [ 'publish_actions' ] ) . '" target="_top">Login</a>';