wordpress - disable all rss and pingbacks and trackbacks on dev/staging sites

functions.php

<?php

if( IS_DEV_SITE ) {
//Disable RSS Feeds functions
add_action('do_feed', array( $this, 'disabler_kill_rss' ), 1);
add_action('do_feed_rdf', array( $this, 'disabler_kill_rss' ), 1);
add_action('do_feed_rss', array( $this, 'disabler_kill_rss' ), 1);
add_action('do_feed_rss2', array( $this, 'disabler_kill_rss' ), 1);
add_action('do_feed_atom', array( $this, 'disabler_kill_rss' ), 1);
if(function_exists('disabler_kill_rss')) {
	function disabler_kill_rss(){
		wp_die( _e("Feeds disabled.", '') );
	}
}

//Remove feed link from header
//remove_action( 'wp_head', 'feed_links_extra', 3 ); //Extra feeds such as category feeds
//remove_action( 'wp_head', 'feed_links', 2 ); // General feeds: Post and Comment Feed


// Disable X-Pingback HTTP Header.
add_filter('wp_headers', function($headers, $wp_query){
    if(isset($headers['X-Pingback'])){
        // Drop X-Pingback
        unset($headers['X-Pingback']);
    }
    return $headers;
}, 11, 2);
// Disable XMLRPC by hijacking and blocking the option.
add_filter('pre_option_enable_xmlrpc', function($state){
    return '0'; // return $state; // To leave XMLRPC intact and drop just Pingback
});

// Remove rsd_link from filters (<link rel="EditURI" />).
//add_action('wp', function(){ remove_action('wp_head', 'rsd_link'); }, 9);

// Hijack pingback_url for get_bloginfo (<link rel="pingback" />).
//add_filter('bloginfo_url', function($output, $property){return ($property == 'pingback_url') ? null : $output;}, 11, 2);

// Just disable pingback.ping functionality while leaving XMLRPC intact?
add_action('xmlrpc_call', function($method){
    if($method != 'pingback.ping') return;
    wp_die(
        'Pingback functionality is disabled on this Blog.',
        'Pingback Disabled!',
        array('response' => 403)
    );
});
}
?>