Creating a Starter Site - Custom Functions - Core

cfcore.php

<?php
   /*
   Plugin Name: Custom Core Functions
   Plugin URI: https://nathaningram.com
   Description: Customize the WP Core
   Version: 2023.11
   Author: Nathan Ingram
   Author URI: https://nathaningram.com
   License: GPL2
   */


// Security Check

if (!defined('ABSPATH')) {
    die();
}


//Disable Automatic Theme and Plugin Autoupdates

add_filter( 'plugins_auto_update_enabled', '__return_false' );
add_filter( 'themes_auto_update_enabled', '__return_false' );



// Disable Autoupdate Emails

add_filter( 'auto_plugin_update_send_email', '__return_false' );
add_filter( 'auto_theme_update_send_email', '__return_false' );


// Disable Emojis

function ni_disable_emojis() {
 remove_action( 'wp_head', 'print_emoji_detection_script', 7 );
 remove_action( 'admin_print_scripts', 'print_emoji_detection_script' );
 remove_action( 'wp_print_styles', 'print_emoji_styles' );
 remove_action( 'admin_print_styles', 'print_emoji_styles' ); 
 remove_filter( 'the_content_feed', 'wp_staticize_emoji' );
 remove_filter( 'comment_text_rss', 'wp_staticize_emoji' ); 
 remove_filter( 'wp_mail', 'wp_staticize_emoji_for_email' );
 add_filter( 'tiny_mce_plugins', 'ni_disable_emojis_tinymce' );
 add_filter( 'wp_resource_hints', 'ni_disable_emojis_remove_dns_prefetch', 10, 2 );
}
add_action( 'init', 'ni_disable_emojis' );
function ni_disable_emojis_tinymce( $plugins ) {
 if ( is_array( $plugins ) ) {
 return array_diff( $plugins, array( 'wpemoji' ) );
 } else {
 return array();
 }
}
function ni_disable_emojis_remove_dns_prefetch( $urls, $relation_type ) {
 if ( 'dns-prefetch' == $relation_type ) {
 $emoji_svg_url = apply_filters( 'emoji_svg_url', 'https://s.w.org/images/core/emoji/2/svg/' );
 $urls = array_diff( $urls, array( $emoji_svg_url ) );
 }
return $urls;
}


// Disable Feeds

function ni_clean_feeds() {
// Redirects all feeds to home page.
	$url = site_url();
	wp_redirect( $url );
}

add_action( 'do_feed', 'ni_clean_feeds', 1 );
add_action( 'do_feed_rdf',  'ni_clean_feeds', 1 );
add_action( 'do_feed_rss',  'ni_clean_feeds', 1 );
add_action( 'do_feed_rss2', 'ni_clean_feeds', 1 );
add_action( 'do_feed_atom', 'ni_clean_feeds', 1 );
add_action( 'do_feed_rss2_comments', 'ni_clean_feeds', 1 );
add_action( 'do_feed_atom_comments', 'ni_clean_feeds', 1 );


// Clean Up WP_Head

remove_action( 'wp_head', 'wp_generator' );                           // Removes WordPress version.
remove_action( 'wp_head', 'wp_shortlink_wp_head', 10, 0 );            // Removes shortlink.
remove_action( 'wp_head', 'rsd_link' );                               // Removes Really Simple Discovery link.
remove_action( 'wp_head', 'feed_links', 2 );                          // Removes RSS feed links.
remove_action( 'wp_head', 'feed_links_extra', 3 );                    // Removes all extra RSS feed links.
remove_action( 'wp_head', 'wlwmanifest_link' );                       // Removes wlwmanifest.xml.
remove_action( 'wp_head', 'wp_resource_hints', 2 );                   // Removes meta rel=dns-prefetch href=//s.w.org
remove_action( 'wp_head', 'adjacent_posts_rel_link_wp_head', 10, 0 ); // Removes relational links for the posts.
remove_action( 'wp_head', 'wp_oembed_add_discovery_links', 10 );      // Removes oEmbeds.


// Disable Post Formats

function ni_remove_post_formats() {
	remove_theme_support('post-formats');
}
add_action( 'after_setup_theme', 'ni_remove_post_formats', 11 );



// Disable New User Registration Emails to Admin
// Code taken from Disable User Registration Notification Emails by Potent Plugins

add_action('init', 'pp_durne_init');

function pp_durne_init() {
	// Unhook the actions from wp-includes/default-filters.php
	remove_action('register_new_user', 'wp_send_new_user_notifications');
	remove_action('edit_user_created_user', 'wp_send_new_user_notifications', 10, 2);
	// Replace with our action that sends the user email only
	add_action('register_new_user', 'pp_durne_send_notification');
	add_action('edit_user_created_user', 'pp_durne_send_notification', 10, 2);
}
function pp_durne_send_notification($userId, $to='both') {
	if (empty($to) || $to == 'admin') {
		// Admin only, so we don't do anything
		return;
	}
	// For 'both' or 'user', we notify only the user
	wp_send_new_user_notifications($userId, 'user');
}


// Disable User Password Change Emails to Admin

if ( ! function_exists( 'wp_password_change_notification' ) ) {
    function wp_password_change_notification( $user ) {
        return;
    }
}


// Sort Settings and Tools Menu Items Alphabetically

function ni_sort_settings_tools_menu_items_alphabetically() {
    global $submenu;
    $menus_to_sort = array(
        'options-general.php', // Settings menu
        'tools.php' // Tools menu
    );
    foreach ($menus_to_sort as $menu_slug) {
        // Check if the menu exists
        if (isset($submenu[$menu_slug]) && is_array($submenu[$menu_slug])) {
            // Sort the items under the menu alphabetically
            usort($submenu[$menu_slug], function ($a, $b) use ($menu_slug) {
                // Ensure both array elements have the 0-index set and are strings
                if (isset($a[0]) && isset($b[0]) && is_string($a[0]) && is_string($b[0])) {
                    // Prioritize 'General' item if on Settings menu
                    if ($menu_slug === 'options-general.php') {
                        if (isset($a[2]) && $a[2] === $menu_slug) {
                            return -1;
                        }
                        if (isset($b[2]) && $b[2] === $menu_slug) {
                            return 1;
                        }
                    }
                    return strcasecmp($a[0], $b[0]);
                }
                return 0;
            });
            // Update the href of the first link to go to the corresponding page
            if (isset($submenu[$menu_slug][0]) && is_array($submenu[$menu_slug][0])) {
                $submenu[$menu_slug][0][2] = $menu_slug;
            }
        }
    }
}
add_action('admin_menu', 'ni_sort_settings_tools_menu_items_alphabetically', 999);