[SmartCrawl] - Custom Permalink. Allow to define a custom slug name for sitemap

wpmudev-smartcrawl-custom-permalink.php

<?php
/**
* Plugin Name: [SmartCrawl] - Custom Permalink
* Plugin URI: https://premium.wpmudev.org/
* Description: Allow to define a custom slug name for sitemap
* Author: Alessandro Kaounas @ WPMUDEV
* Author URI: https://premium.wpmudev.org/
* License: GPLv2 or later
*/

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

// Define custom sitemap slug
define('WPMUDEV_SITEMAP_SLUG', 'demo.xml');

add_action('plugins_loaded', 'wpmudev_smartcrawl_init');

function wpmudev_smartcrawl_init() {
    if (class_exists('Smartcrawl_Controller_Sitemap')) {
        // Remove current action
        remove_action('init', array( Smartcrawl_Controller_Sitemap::get(), 'serve_sitemap' ), 999);
        // Override plugin function
        add_action('init', 'wpmudev_smartcrawl_serve_sitemap');
    }
}

function wpmudev_smartcrawl_custom_permalink() {
    return home_url( false ) . '/' . WPMUDEV_SITEMAP_SLUG;
}

function wpmudev_smartcrawl_serve_sitemap() {

    if ( ! function_exists( 'smartcrawl_get_sitemap_path' ) ) {
        return;
    }
    if ( ! Smartcrawl_Settings::get_setting( 'sitemap' ) ) {
        return;
    }
    
    $instance = Smartcrawl_Controller_Sitemap::get();

    $url_path = $instance->get_url_part( $_SERVER['REQUEST_URI'], PHP_URL_PATH );

    $path = smartcrawl_get_sitemap_path();

    $is_gzip = preg_match( '~\.gz$~i', $url_path );
    $path = $is_gzip ? "{$path}.gz" : $path;

    // Report it
    if ( preg_match( '~' . preg_quote( '/' . WPMUDEV_SITEMAP_SLUG ) . '(\.gz)?$~i', $url_path ) ) {
        // Check if any updates are required
        if ( ! file_exists( $path ) || wpmudev_smartcrawl_is_sitemap_dirty() ) {
            wpmudev_smartcrawl_update_sitemap();
        }

        // Serve the file if it exists
        if ( file_exists( $path ) ) {
            if ( $is_gzip ) {
                header( 'Content-Encoding: gzip' );
            }
            header( 'Content-Type: text/xml' );
            die( smartcrawl_file_get_contents( $path ) ); // phpcs:ignore -- Can't escape XML
        } else {
            wp_die( esc_html__( 'The sitemap file was not found.', 'wds' ) );
        }
    }
}

function wpmudev_smartcrawl_is_sitemap_dirty() {
    return ! Smartcrawl_Xml_Sitemap::get()->is_sitemap_pristine();
}

function wpmudev_smartcrawl_update_sitemap() {
    Smartcrawl_Xml_Sitemap::get()->generate_sitemap();
    Smartcrawl_Xml_Sitemap::get()->set_sitemap_pristine( true );
}