class-nginx-helper-admin.php

<?php
/**
 * The admin-specific functionality of the plugin.
 *
 * @link       https://rtcamp.com/nginx-helper/
 * @since      2.0.0
 *
 * @package    nginx-helper
 * @subpackage nginx-helper/admin
 */

/**
 * The admin-specific functionality of the plugin.
 *
 * Defines the plugin name, version, and two examples hooks for how to
 * enqueue the admin-specific stylesheet and JavaScript.
 *
 * @package    nginx-helper
 * @subpackage nginx-helper/admin
 * @author     rtCamp
 */
class Nginx_Helper_Admin {
	
	/**
	 * The ID of this plugin.
	 *
	 * @since    2.0.0
	 * @access   private
	 * @var      string    $plugin_name    The ID of this plugin.
	 */
	private $plugin_name;
	
	/**
	 * The version of this plugin.
	 *
	 * @since    2.0.0
	 * @access   private
	 * @var      string    $version    The current version of this plugin.
	 */
	private $version;
	
	/**
	 * Various settings tabs.
	 *
	 * @since    2.0.0
	 * @access   private
	 * @var      string    $settings_tabs    Various settings tabs.
	 */
	private $settings_tabs;
	
	/**
	 * Purge options.
	 *
	 * @since    2.0.0
	 * @access   public
	 * @var      string[]    $options    Purge options.
	 */
	public $options;
	
	/**
	 * WP-CLI Command.
	 *
	 * @since    2.0.0
	 * @access   public
	 * @var      string    $options    WP-CLI Command.
	 */
	const WP_CLI_COMMAND = 'nginx-helper';
	
	/**
	 * Initialize the class and set its properties.
	 *
	 * @since    2.0.0
	 * @param      string $plugin_name       The name of this plugin.
	 * @param      string $version    The version of this plugin.
	 */
	public function __construct( $plugin_name, $version ) {
		
		$this->plugin_name = $plugin_name;
		$this->version     = $version;
		
		$this->options = $this->nginx_helper_settings();
	}
	
	/**
	 * Initialize the settings tab.
	 * Required since i18n is used in the settings tab which can be invoked only after init hook since WordPress 6.7
	 */
	public function initialize_setting_tab() {
		
		/**
		 * Define settings tabs
		 */
		$this->settings_tabs = apply_filters(
			'rt_nginx_helper_settings_tabs',
			array(
				'general' => array(
					'menu_title' => __( 'General', 'nginx-helper' ),
					'menu_slug'  => 'general',
				),
				'support' => array(
					'menu_title' => __( 'Support', 'nginx-helper' ),
					'menu_slug'  => 'support',
				),
			)
		);
	}
	
	
	/**
	 * Register the stylesheets for the admin area.
	 *
	 * @since    2.0.0
	 *
	 * @param string $hook The current admin page.
	 */
	public function enqueue_styles( $hook ) {
		
		/**
		 * This function is provided for demonstration purposes only.
		 *
		 * An instance of this class should be passed to the run() function
		 * defined in Nginx_Helper_Loader as all of the hooks are defined
		 * in that particular class.
		 *
		 * The Nginx_Helper_Loader will then create the relationship
		 * between the defined hooks and the functions defined in this
		 * class.
		 */
		
		if ( 'settings_page_nginx' !== $hook ) {
			return;
		}
		
		wp_enqueue_style( $this->plugin_name . '-icons', plugin_dir_url( __FILE__ ) . 'icons/css/nginx-fontello.css', array(), $this->version, 'all' );
		wp_enqueue_style( $this->plugin_name, plugin_dir_url( __FILE__ ) . 'css/nginx-helper-admin.css', array(), $this->version, 'all' );
		
	}
	
	/**
	 * Register the JavaScript for the admin area.
	 *
	 * @since    2.0.0
	 *
	 * @param string $hook The current admin page.
	 */
	public function enqueue_scripts( $hook ) {
		
		/**
		 * This function is provided for demonstration purposes only.
		 *
		 * An instance of this class should be passed to the run() function
		 * defined in Nginx_Helper_Loader as all of the hooks are defined
		 * in that particular class.
		 *
		 * The Nginx_Helper_Loader will then create the relationship
		 * between the defined hooks and the functions defined in this
		 * class.
		 */
		
		if ( 'settings_page_nginx' !== $hook ) {
			return;
		}
		
		wp_enqueue_script( $this->plugin_name, plugin_dir_url( __FILE__ ) . 'js/nginx-helper-admin.js', array( 'jquery' ), $this->version, false );
		
		$do_localize = array(
			'purge_confirm_string' => esc_html__( 'Purging entire cache is not recommended. Would you like to continue?', 'nginx-helper' ),
		);
		wp_localize_script( $this->plugin_name, 'nginx_helper', $do_localize );
		
	}
	
	/**
	 * Add admin menu.
	 *
	 * @since    2.0.0
	 */
	public function nginx_helper_admin_menu() {
		
		if ( is_multisite() ) {
			
			add_submenu_page(
				'settings.php',
				__( 'Nginx Helper', 'nginx-helper' ),
				__( 'Nginx Helper', 'nginx-helper' ),
				'manage_options',
				'nginx',
				array( &$this, 'nginx_helper_setting_page' )
			);
			
		} else {
			
			add_submenu_page(
				'options-general.php',
				__( 'Nginx Helper', 'nginx-helper' ),
				__( 'Nginx Helper', 'nginx-helper' ),
				'manage_options',
				'nginx',
				array( &$this, 'nginx_helper_setting_page' )
			);
			
		}
		
	}
	
	/**
	 * Function to add toolbar purge link.
	 *
	 * @param object $wp_admin_bar Admin bar object.
	 */
	public function nginx_helper_toolbar_purge_link( $wp_admin_bar ) {
		
		if ( ! current_user_can( 'manage_options' ) ) {
			return;
		}
		
		if ( is_admin() ) {
			$nginx_helper_urls = 'all';
			$link_title        = __( 'Purge Cache', 'nginx-helper' );
		} else {
			$nginx_helper_urls = 'current-url';
			$link_title        = __( 'Purge Current Page', 'nginx-helper' );
		}
		
		$purge_url = add_query_arg(
			array(
				'nginx_helper_action' => 'purge',
				'nginx_helper_urls'   => $nginx_helper_urls,
			)
		);
		
		$nonced_url = wp_nonce_url( $purge_url, 'nginx_helper-purge_all' );
		
		$wp_admin_bar->add_menu(
			array(
				'id'    => 'nginx-helper-purge-all',
				'title' => $link_title,
				'href'  => $nonced_url,
				'meta'  => array( 'title' => $link_title ),
			)
		);
		
	}
	
	/**
	 * Display settings.
	 *
	 * @global $string $pagenow Contain current admin page.
	 *
	 * @since    2.0.0
	 */
	public function nginx_helper_setting_page() {
		include plugin_dir_path( __FILE__ ) . 'partials/nginx-helper-admin-display.php';
	}
	
	/**
	 * Default settings.
	 *
	 * @since    2.0.0
	 * @return array
	 */
	public function nginx_helper_default_settings() {
		
		return array(
			'enable_purge'                     => 0,
			'cache_method'                     => 'enable_fastcgi',
			'purge_method'                     => 'get_request',
			'enable_map'                       => 0,
			'enable_log'                       => 0,
			'log_level'                        => 'INFO',
			'log_filesize'                     => '5',
			'enable_stamp'                     => 0,
			'purge_homepage_on_edit'           => 1,
			'purge_homepage_on_del'            => 1,
			'purge_archive_on_edit'            => 1,
			'purge_archive_on_del'             => 1,
			'purge_archive_on_new_comment'     => 0,
			'purge_archive_on_deleted_comment' => 0,
			'purge_page_on_mod'                => 1,
			'purge_page_on_new_comment'        => 1,
			'purge_page_on_deleted_comment'    => 1,
			'purge_feeds'                      => 1,
			'redis_hostname'                   => '127.0.0.1',
			'redis_port'                       => '6379',
			'redis_prefix'                     => 'nginx-cache:',
			'purge_url'                        => '',
			'redis_enabled_by_constant'        => 0,
			'preload_cache'                    => 0,
			'is_cache_preloaded'               => 0
		);
		
	}
    
    public function store_default_options() {
        $options = get_site_option( 'rt_wp_nginx_helper_options', array() );
        $default_settings = $this->nginx_helper_default_settings();
        
        $removable_default_settings = array(
            'redis_port',
            'redis_prefix',
            'redis_hostname',
            'redis_database',
            'redis_unix_socket'
        );
        
        // Remove all the keys that are not to be stored by default.
        foreach ( $removable_default_settings as $removable_key ) {
            unset( $default_settings[ $removable_key ] );
        }
        
        $diffed_options = wp_parse_args( $options, $default_settings );
        
        add_site_option( 'rt_wp_nginx_helper_options', $diffed_options );
    }

	/**
	 * Get settings.
	 *
	 * @since    2.0.0
	 */
	public function nginx_helper_settings() {
		
		$options = get_site_option(
			'rt_wp_nginx_helper_options',
			array(
				'redis_hostname' => '127.0.0.1',
				'redis_port'     => '6379',
				'redis_prefix'   => 'nginx-cache:',
			)
		);
		
		$data = wp_parse_args(
			$options,
			$this->nginx_helper_default_settings()
		);
		
		$is_redis_enabled = (
			defined( 'RT_WP_NGINX_HELPER_REDIS_HOSTNAME' ) &&
			defined( 'RT_WP_NGINX_HELPER_REDIS_PORT' ) &&
			defined( 'RT_WP_NGINX_HELPER_REDIS_PREFIX' )
		);
		
		if ( ! $is_redis_enabled ) {
			return $data;
		}
		
		$data['redis_enabled_by_constant'] = $is_redis_enabled;
		$data['enable_purge']              = $is_redis_enabled;
		$data['cache_method']              = 'enable_redis';
		$data['redis_hostname']            = RT_WP_NGINX_HELPER_REDIS_HOSTNAME;
		$data['redis_port']                = RT_WP_NGINX_HELPER_REDIS_PORT;
		$data['redis_prefix']              = RT_WP_NGINX_HELPER_REDIS_PREFIX;
		
		return $data;
		
	}
	
	/**
	 * Nginx helper setting link function.
	 *
	 * @param array $links links.
	 *
	 * @return mixed
	 */
	public function nginx_helper_settings_link( $links ) {
		
		if ( is_network_admin() ) {
			$setting_page = 'settings.php';
		} else {
			$setting_page = 'options-general.php';
		}
		
		$settings_link = '<a href="' . network_admin_url( $setting_page . '?page=nginx' ) . '">' . __( 'Settings', 'nginx-helper' ) . '</a>';
		array_unshift( $links, $settings_link );
		
		return $links;
		
	}
	
	/**
	 * Check if the nginx log is enabled.
	 *
	 * @since 2.2.4
	 * @return    boolean
	 */
	public function is_nginx_log_enabled() {
		
		$options = get_site_option( 'rt_wp_nginx_helper_options', array() );
		
		if ( ! empty( $options['enable_log'] ) && 1 === (int) $options['enable_log'] ) {
			return true;
		}
		
		if ( defined( 'NGINX_HELPER_LOG' ) && true === NGINX_HELPER_LOG ) {
			return true;
		}
		
		return false;
	}
	
	/**
	 * Retrieve the asset path.
	 *
	 * @since     2.0.0
	 * @return    string    asset path of the plugin.
	 */
	public function functional_asset_path() {
		
		$log_path = WP_CONTENT_DIR . '/uploads/nginx-helper/';
		
		return apply_filters( 'nginx_asset_path', $log_path );
		
	}
	
	/**
	 * Retrieve the asset url.
	 *
	 * @since     2.0.0
	 * @return    string    asset url of the plugin.
	 */
	public function functional_asset_url() {
		
		$log_url = WP_CONTENT_URL . '/uploads/nginx-helper/';
		
		return apply_filters( 'nginx_asset_url', $log_url );
		
	}
	
	/**
	 * Get latest news.
	 *
	 * @since     2.0.0
	 */
	public function nginx_helper_get_feeds() {
		
		// Get RSS Feed(s).
		require_once ABSPATH . WPINC . '/feed.php';
		
		$maxitems  = 0;
		$rss_items = array();
		
		// Get a SimplePie feed object from the specified feed source.
		$rss = fetch_feed( 'https://rtcamp.com/blog/feed/' );
		
		if ( ! is_wp_error( $rss ) ) { // Checks that the object is created correctly.
			
			// Figure out how many total items there are, but limit it to 5.
			$maxitems = $rss->get_item_quantity( 5 );
			// Build an array of all the items, starting with element 0 (first element).
			$rss_items = $rss->get_items( 0, $maxitems );
			
		}
		?>
		<ul role="list">
			<?php
			if ( 0 === $maxitems ) {
				echo '<li role="listitem">' . esc_html_e( 'No items', 'nginx-helper' ) . '.</li>';
			} else {
				
				// Loop through each feed item and display each item as a hyperlink.
				foreach ( $rss_items as $item ) {
					?>
					<li role="listitem">
						<?php
						printf(
							'<a href="%s" title="%s">%s</a>',
							esc_url( $item->get_permalink() ),
							esc_attr__( 'Posted ', 'nginx-helper' ) . esc_attr( $item->get_date( 'j F Y | g:i a' ) ),
							esc_html( $item->get_title() )
						);
						?>
					</li>
					<?php
				}
			}
			?>
		</ul>
		<?php
		die();
		
	}
	
	/**
	 * Add time stamps in html.
	 */
	public function add_timestamps() {
		
		global $pagenow;
		
		if ( is_admin() || 1 !== (int) $this->options['enable_purge'] || 1 !== (int) $this->options['enable_stamp'] ) {
			return;
		}
		
		if ( ! empty( $pagenow ) && 'wp-login.php' === $pagenow ) {
			return;
		}
		
		foreach ( headers_list() as $header ) {
			list( $key, $value ) = explode( ':', $header, 2 );
			$key                 = strtolower( $key );
			if ( 'content-type' === $key && strpos( trim( $value ), 'text/html' ) !== 0 ) {
				return;
			}
			if ( 'content-type' === $key ) {
				break;
			}
		}
		
		/**
		 * Don't add timestamp if run from ajax, cron or wpcli.
		 */
		if ( defined( 'DOING_AJAX' ) && DOING_AJAX ) {
			return;
		}
		
		if ( defined( 'DOING_CRON' ) && DOING_CRON ) {
			return;
		}
		
		if ( defined( 'WP_CLI' ) && WP_CLI ) {
			return;
		}
		
		$timestamps = "\n<!--" .
			'Cached using Nginx-Helper on ' . current_time( 'mysql' ) . '. ' .
			'It took ' . get_num_queries() . ' queries executed in ' . timer_stop() . ' seconds.' .
			"-->\n" .
			'<!--Visit http://wordpress.org/extend/plugins/nginx-helper/faq/ for more details-->';
		
		echo wp_kses( $timestamps, array() );
		
	}
	
	/**
	 * Get map
	 *
	 * @global object $wpdb
	 *
	 * @return string
	 */
	public function get_map() {
		
		if ( ! $this->options['enable_map'] ) {
			return;
		}
		
		if ( is_multisite() ) {
			
			global $wpdb;
			
			$rt_all_blogs = $wpdb->get_results(
				$wpdb->prepare(
					'SELECT blog_id, domain, path FROM ' . $wpdb->blogs . " WHERE site_id = %d AND archived = '0' AND mature = '0' AND spam = '0' AND deleted = '0'",
					$wpdb->siteid
				)
			);
			
			$wpdb->dmtable = $wpdb->base_prefix . 'domain_mapping';
			
			$rt_domain_map_sites = '';
			
			if ( $wpdb->get_var( "SHOW TABLES LIKE '{$wpdb->dmtable}'" ) === $wpdb->dmtable ) { // phpcs:ignore
				$rt_domain_map_sites = $wpdb->get_results( "SELECT blog_id, domain FROM {$wpdb->dmtable} ORDER BY id DESC" );
			}
			
			$rt_nginx_map       = '';
			$rt_nginx_map_array = array();
			
			if ( $rt_all_blogs ) {
				
				foreach ( $rt_all_blogs as $blog ) {
					
					if ( true === SUBDOMAIN_INSTALL ) {
						$rt_nginx_map_array[ $blog->domain ] = $blog->blog_id;
					} else {
						
						if ( 1 !== $blog->blog_id ) {
							$rt_nginx_map_array[ $blog->path ] = $blog->blog_id;
						}
					}
				}
			}
			
			if ( $rt_domain_map_sites ) {
				
				foreach ( $rt_domain_map_sites as $site ) {
					$rt_nginx_map_array[ $site->domain ] = $site->blog_id;
				}
			}
			
			foreach ( $rt_nginx_map_array as $domain => $domain_id ) {
				$rt_nginx_map .= "\t" . $domain . "\t" . $domain_id . ";\n";
			}
			
			return $rt_nginx_map;
			
		}
		
	}
	
	/**
	 * Update map
	 */
	public function update_map() {
		
		if ( is_multisite() ) {
			
			$rt_nginx_map = $this->get_map();
			
			$fp = fopen( $this->functional_asset_path() . 'map.conf', 'w+' );
			if ( $fp ) {
				fwrite( $fp, $rt_nginx_map );
				fclose( $fp );
			}
		}
		
	}
	
	/**
	 * Purge url when post status is changed.
	 *
	 * @global string $blog_id Blog id.
	 * @global object $nginx_purger Nginx purger variable.
	 *
	 * @param string $new_status New status.
	 * @param string $old_status Old status.
	 * @param object $post Post object.
	 */
	public function set_future_post_option_on_future_status( $new_status, $old_status, $post ) {
		
		global $blog_id, $nginx_purger;
		
		$exclude_post_types = array( 'nav_menu_item' );
		
		if ( in_array( $post->post_type, $exclude_post_types, true ) ) {
			return;
		}
		
		if ( ! $this->options['enable_purge'] || $this->is_import_request() ) {
			return;
		}
		
		$purge_status = array( 'publish', 'future' );
		
		if ( in_array( $old_status, $purge_status, true ) || in_array( $new_status, $purge_status, true ) ) {
			
			$nginx_purger->log( 'Purge post on transition post STATUS from ' . $old_status . ' to ' . $new_status );
			$nginx_purger->purge_post( $post->ID );
			
		}
		
		if (
			'future' === $new_status && $post && 'future' === $post->post_status &&
			(
				( 'post' === $post->post_type || 'page' === $post->post_type ) ||
				(
					isset( $this->options['custom_post_types_recognized'] ) &&
					in_array( $post->post_type, $this->options['custom_post_types_recognized'], true )
				)
			)
		) {
			
			$nginx_purger->log( 'Set/update future_posts option ( post id = ' . $post->ID . ' and blog id = ' . $blog_id . ' )' );
			$this->options['future_posts'][ $blog_id ][ $post->ID ] = strtotime( $post->post_date_gmt ) + 60;
			update_site_option( 'rt_wp_nginx_helper_options', $this->options );
			
		}
		
	}
	
	/**
	 * Unset future post option on delete
	 *
	 * @global string $blog_id Blog id.
	 * @global object $nginx_purger Nginx helper object.
	 *
	 * @param int $post_id Post id.
	 */
	public function unset_future_post_option_on_delete( $post_id ) {
		
		global $blog_id, $nginx_purger;
		
		if (
			! $this->options['enable_purge'] ||
			empty( $this->options['future_posts'] ) ||
			empty( $this->options['future_posts'][ $blog_id ] ) ||
			isset( $this->options['future_posts'][ $blog_id ][ $post_id ] ) ||
			wp_is_post_revision( $post_id )
		) {
			return;
		}
		
		$nginx_purger->log( 'Unset future_posts option ( post id = ' . $post_id . ' and blog id = ' . $blog_id . ' )' );
		
		unset( $this->options['future_posts'][ $blog_id ][ $post_id ] );
		
		if ( ! count( $this->options['future_posts'][ $blog_id ] ) ) {
			unset( $this->options['future_posts'][ $blog_id ] );
		}
		
		update_site_option( 'rt_wp_nginx_helper_options', $this->options );
	}
	
	/**
	 * Update map when new blog added in multisite.
	 *
	 * @global object $nginx_purger Nginx purger class object.
	 *
	 * @param string $blog_id blog id.
	 */
	public function update_new_blog_options( $blog_id ) {
		
		global $nginx_purger;
		
		$nginx_purger->log( "New site added ( id $blog_id )" );
		$this->update_map();
		$nginx_purger->log( "New site added to nginx map ( id $blog_id )" );
		$helper_options = $this->nginx_helper_default_settings();
		update_blog_option( $blog_id, 'rt_wp_nginx_helper_options', $helper_options );
		$nginx_purger->log( "Default options updated for the new blog ( id $blog_id )" );
		
	}
	
	/**
	 * Purge all urls.
	 * Purge current page cache when purging is requested from front
	 * and all urls when requested from admin dashboard.
	 *
	 * @global object $nginx_purger
	 */
	public function purge_all() {
		
		if ( $this->is_import_request() ) {
			return;
		}
		
		global $nginx_purger, $wp;
		
		$method = null;
		if ( isset( $_SERVER['REQUEST_METHOD'] ) ) {
			$method = wp_strip_all_tags( $_SERVER['REQUEST_METHOD'] );
		}
		
		$action = '';
		if ( 'POST' === $method ) {
			if ( isset( $_POST['nginx_helper_action'] ) ) {
				$action = wp_strip_all_tags( $_POST['nginx_helper_action'] );
			}
		} else {
			if ( isset( $_GET['nginx_helper_action'] ) ) {
				$action = wp_strip_all_tags( $_GET['nginx_helper_action'] );
			}
		}
		
		if ( empty( $action ) ) {
			return;
		}
		
		if ( ! current_user_can( 'manage_options' ) ) {
			wp_die( 'Sorry, you do not have the necessary privileges to edit these options.' );
		}
		
		if ( 'done' === $action ) {
			
			add_action( 'admin_notices', array( &$this, 'display_notices' ) );
			add_action( 'network_admin_notices', array( &$this, 'display_notices' ) );
			return;
			
		}
		
		check_admin_referer( 'nginx_helper-purge_all' );
		
		$current_url = user_trailingslashit( home_url( $wp->request ) );
		
		if ( ! is_admin() ) {
			$action       = 'purge_current_page';
			$redirect_url = $current_url;
		} else {
			$redirect_url = add_query_arg( array( 'nginx_helper_action' => 'done' ) );
		}
		
		switch ( $action ) {
			case 'purge':
				$nginx_purger->purge_all();
				break;
			case 'purge_current_page':
				$nginx_purger->purge_url( $current_url );
				break;
		}
		
		if ( 'purge' === $action ) {
			
			/**
			 * Fire an action after the entire cache has been purged whatever caching type is used.
			 *
			 * @since 2.2.2
			 */
			do_action( 'rt_nginx_helper_after_purge_all' );
			
		}
		
		wp_redirect( esc_url_raw( $redirect_url ) );
		exit();
		
	}
	
	/**
	 * Dispay plugin notices.
	 */
	public function display_notices() {
		echo '<div class="updated"><p>' . esc_html__( 'Purge initiated', 'nginx-helper' ) . '</p></div>';
	}
	
	/**
	 * Preloads the cache for the website.
	 *
	 * @return void
	 */
	public function preload_cache() {
		$is_cache_preloaded    = $this->options['is_cache_preloaded'];
		$preload_cache_enabled = $this->options['preload_cache'];
		
		if ( $preload_cache_enabled && false === boolval( $is_cache_preloaded ) ) {
			$this->options['is_cache_preloaded'] = true;
			
			update_site_option( 'rt_wp_nginx_helper_options', $this->options );
			$this->preload_cache_from_sitemap();
		}
	}
	
	/**
	 * This function preloads the cache from sitemap url.
	 *
	 * @return void
	 */
	private function preload_cache_from_sitemap() {
		
		$sitemap_urls = $this->get_index_sitemap_urls();
		$all_urls     = array();
		
		foreach ( $sitemap_urls as $sitemap_url ) {
			$urls     = $this->extract_sitemap_urls( $sitemap_url );
			$all_urls = array_merge( $all_urls, $urls );
		}
		
		$args = array(
			'timeout'   => 1,
			'blocking'  => false,
			'sslverify' => false,
		);
		
		foreach ( $all_urls as $url ) {
			wp_remote_get( esc_url_raw( $url ), $args );
		}
		
	}
	
	/**
	 * Fetches all the sitemap urls for the site.
	 *
	 * @return array
	 */
	private function get_index_sitemap_urls() {
		$sitemaps = wp_sitemaps_get_server()->index->get_sitemap_list();
		$urls     = array();
		foreach ( $sitemaps as $sitemap ) {
			$urls[] = $sitemap['loc'];
		}
		return $urls;
	}
	
	/**
	 * Parse sitemap content and extract all URLs.
	 *
	 * @param string $sitemap_url The URL of the sitemap.
	 * @return array|WP_Error An array of URLs or WP_Error on failure.
	 */
	private function extract_sitemap_urls( $sitemap_url ) {
		$response = wp_remote_get( $sitemap_url );
		
		$urls = array();
		
		if ( is_wp_error( $response ) ) {
			return $urls;
		}
		
		$sitemap_content = wp_remote_retrieve_body( $response );
		
		libxml_use_internal_errors( true );
		$xml = simplexml_load_string( $sitemap_content );
		
		if ( false === $xml ) {
			return new WP_Error( 'sitemap_parse_error', esc_html__( 'Failed to parse the sitemap XML', 'nginx-helper' ) );
		}
		
		$urls = array();
		
		if ( false === $xml ) {
			return $urls;
		}
		
		foreach ( $xml->url as $url ) {
			$urls[] = (string) $url->loc;
		}
		
		return $urls;
	}
	
	/**
	* Determines if the current request is for importing Posts/ WordPress content.
	*
	* @return bool True if the request is for importing, false otherwise.
	*/
	public function is_import_request() {
		$import_query_var   = sanitize_text_field( wp_unslash( $_GET['import'] ?? '' ) ); //phpcs:ignore WordPress.Security.NonceVerification.Recommended -- Nonce is already in the admin dashboard.
		$has_import_started = did_action( 'import_start' );
		
		return ( defined( 'WP_IMPORTING' ) && true === WP_IMPORTING )
			|| 0 !== $has_import_started
			|| ! empty( $import_query_var );
	}
	
	
}