How to check if feed URL was requested?

I’m writing a plugin to block some pages to anonymous users on my site. I already blocked some pages but I can’t get to identify the feed page my-wordpress-site.com/feed.

I’ve tried:

• $GLOBALS['pagenow'] == 'feed'
• is_feed()
• is_page('feed')
• checking on $_SERVER['REQUEST_URI'] and $_SERVER['PATH_INFO']

Any ideas on how to achieve that?

You have not specified exactly when your code runs but you can hook into “request” to check the requested page:

add_filter( 'request', function( $request ){
    if( isset( $request['feed'] ) ){
        //This is a feed request
    }
    return $request;
});

When the requested page is a feed $request, which is an array of query variables, will contain an item called “feed” which is set with the name of the feed like “rss” for example.
https://codex.wordpress.org/Plugin_API/Filter_Reference/request