attachment-slug.php

<?php
/*
 * Plugin Name: Attachment Slugs for WordPress
 * Plugin URI:  https://wordpress.org/plugins/attachment-slug/
 * Description: Enables permalink support for media attachments making the URLs more friendly and great for SEO.
 * Author:      Sébastien Dumont
 * Author URI:  https://sebastiendumont.com
 * Version:     2.0.0
 * Text Domain: attachment-slug
 * Domain Path: /languages/
 * Requires at least: 4.4
 * Requires PHP:      5.6
 *
 * Copyright:   © 2022 Sébastien Dumont
 * License:     GNU General Public License v2.0+
 * License URI: http://www.gnu.org/licenses/gpl-2.0.html
 */

if ( ! class_exists( 'Attachment_Slug' ) ) {
	class Attachment_Slug {

		/**
		 * @var Attachment_Slug - the single instance of the class.
		 *
		 * @access protected
		 *
		 * @static
		 */
		protected static $_instance = null;

		/**
		 * Plugin Version
		 *
		 * @access public
		 *
		 * @static
		 */
		public static $version = '2.0.0';

		/**
		 * Main Attachment_Slug Instance.
		 *
		 * Ensures only one instance of Attachment_Slug is loaded or can be loaded.
		 *
		 * @access public
		 *
		 * @static
		 *
		 * @return Attachment_Slug - Main instance
		 */
		public static function instance() {
			if ( is_null( self::$_instance ) ) {
				self::$_instance = new self();
			}

			return self::$_instance;
		}

		/**
		 * Cloning is forbidden.
		 *
		 * @access public
		 *
		 * @return void
		 */
		public function __clone() {
			_doing_it_wrong( __FUNCTION__, __( 'Cloning this object is forbidden.', 'attachment-slug' ), self::$version );
		} // END __clone()

		/**
		 * Unserializing instances of this class is forbidden.
		 *
		 * @access public
		 *
		 * @return void
		 */
		public function __wakeup() {
			_doing_it_wrong( __FUNCTION__, __( 'Unserializing instances of this class is forbidden.', 'attachment-slug' ), self::$version );
		} // END __wakeup()

		/**
		 * Load the plugin.
		 *
		 * @access public
		 */
		public function __construct() {
			// Check WordPress environment.
			add_action( 'admin_init', array( $this, 'check_wp' ), 12 );

			// Permalink settings for attachments.
			add_action( 'admin_init', array( $this, 'initialize_permalink_settings' ) );

			// Filters the permalink for attachments.
			add_filter( 'attachment_link', array( $this, 'attachment_link'), 10, 2 );

			// Adds the rewrite rule for attachments.
			add_action( 'init', array( $this, 'add_rewrite_rule' ), 10, 0 );

			// Load plugin textdomain.
			add_action( 'init', array( $this, 'load_plugin_textdomain' ) );

			// Edit and Save Attachment.
			if ( is_admin() ) {
				add_action( 'attachment_submitbox_misc_actions', array( $this, 'individual_slug' ), 20 );
				add_action( 'attachment_updated', array( $this, 'save_individual_slug' ), 10, 1 );
			}
		} // END __construct()

		/**
		 * Checks that the WordPress version meets the plugin requirement.
		 *
		 * @access public
		 *
		 * @since 1.0.0
		 *
		 * @global string $wp_version
		 *
		 * @return bool
		 */
		public function check_wp() {
			global $wp_version;

			if ( ! version_compare( $wp_version, '4.4', '>=' ) ) {
				add_action( 'admin_notices', array( $this, 'requirement_wp_notice' ) );
				return false;
			}

			return true;
		} // END check_wp()

		/**
		 * Show the WordPress requirement notice.
		 *
		 * @access public
		 *
		 * @since 1.0.0
		 */
		public function requirement_wp_notice() {
			include( dirname( __FILE__ ) . '/admin/views/html-notice-requirement-wp.php' );
		} // END requirement_wp_notice()

		/** 
		 * Includes the permalink settings.
		 *
		 * @access public
		 */
		public function initialize_permalink_settings() {
			include_once( dirname( __FILE__ ) . '/admin/class-as-permalink-settings.php' );
		} // END initialize_permalink_settings()

		/**
		 * Filters the attachment links
		 *
		 * @access public
		 *
		 * @return string $link
		 */
		public function attachment_link( $link, $post_id ){
			$permalinks = $this->aswp_get_permalink_structure();

			$attachment_slug = $permalinks['attachment_base']; // Attachment base or custom base.

			if ( ! empty( $attachment_slug ) ) {
				$post = get_post( $post_id );
				$link = home_url( '/' . $attachment_slug . '/' . $post->post_name . '/' );
			}

			return $link;
		} // END attachment_link()

		/**
		 * Add the Attachment Slug rewrite rule
		 *
		 * @access public
		 *
		 * @return void
		 */
		public function add_rewrite_rule() {
			$permalinks = $this->aswp_get_permalink_structure();

			$attachment_slug = ! empty( $permalinks['attachment_base'] ) ? trim( $permalinks['attachment_base'], '/' ) : ''; // Attachment base or custom base.

			if ( ! empty( $attachment_slug ) ) {
				// Add the rewrite rule.
				add_rewrite_rule( '^' . $attachment_slug . '/([^/]*)/?', 'index.php?attachment=$matches[1]', 'top' );
			}
		} // END add_rewrite_rule()

		/**
		 * Load the plugin translations if any ready.
		 *
		 * Note: the first-loaded translation file overrides any following ones if the same translation is present.
		 *
		 * Locales found in:
		 *      - WP_LANG_DIR/attachment-slug/attachment-slug-LOCALE.mo
		 *      - WP_LANG_DIR/plugins/attachment-slug-LOCALE.mo
		 *
		 * @access public
		 *
		 * @static
		 *
		 * @since   1.0.0 Introduced.
		 * @version 2.0.0
		 */
		public static function load_plugin_textdomain() {
			if ( function_exists( 'determine_locale' ) ) {
				$locale = determine_locale();
			} else {
				$locale = is_admin() ? get_user_locale() : get_locale();
			}

			$locale = apply_filters( 'plugin_locale', $locale, 'attachment-slug' );

			unload_textdomain( 'attachment-slug' );
			load_textdomain( 'attachment-slug', WP_LANG_DIR . '/attachment-slug/attachment-slug-' . $locale . '.mo' );
			load_plugin_textdomain( 'attachment-slug', false, plugin_basename( dirname( __FILE__ ) ) . '/languages' );
		} // END load_plugin_textdomain()

		/**
		 * Adds a text field to allow an individual attachment 
		 * to have a unique slug.
		 *
		 * @access public
		 *
		 * @since 1.0.0
		 *
		 * @global object $post WP_Post
		 *
		 * @return void
 		 */
		public function individual_slug() {
			global $post;

			$slug = $post->post_name;

			echo '<div class="misc-pub-section"><h4 style="font-size: 14px; margin-top: 5px; margin-bottom: 0;">' . __( 'Attachment Slug', 'attachment-slug' ) . '</h4></div>';

			echo '<div class="misc-pub-section">' . esc_attr__( 'Here you can change the permalink slug for this attachment.', 'attachment-slug' ) . '</div>';

			echo '<div class="misc-pub-section misc-pub-attachment-slug"><label for="attachment_slug">' . __( 'Attachment Slug', 'attachment-slug' ) . ':</label>
				<input type="text" class="widefat urlfield" name="attachment_slug" id="attachment_slug" value="' . $slug . '">
			</div>';
		} // END individual_slug()

		/**
		 * Saves the individual slug for the attachment
		 *
		 * @access public
		 *
		 * @since 1.0.0
		 *
		 * @param int $post_ID Post ID.
		 *
		 * @global $wpdb WordPress database abstraction object.
		 */
		public function save_individual_slug( $post_ID ) {
			global $wpdb;

			$new_slug = isset( $_POST['attachment_slug'] ) ? trim( strip_tags( sanitize_title( $_POST['attachment_slug'] ) ) ) : '';

			if ( ! empty( $new_slug ) ) {
				$wpdb->query( $wpdb->prepare("
					UPDATE $wpdb->posts
					SET post_name = %s
					WHERE ID = %d
					",
					$new_slug,
					$post_ID
				) );
			}
		} // END save_individual_slug()

		/**
		 * Get permalink settings for attachments.
		 *
		 * This is more inline with WP core behavior which does not localize slugs.
		 *
		 * @access public
		 *
		 * @since 2.0.0
		 *
		 * @static
		 *
		 * @return array
		 */
		public static function aswp_get_permalink_structure() {
			$saved_permalinks = (array) get_option( 'attachment_permalink', array() );
			$permalinks       = wp_parse_args(
				array_filter( $saved_permalinks ),
				array(
					'attachment_base' => '',
					'custom'          => ''
				)
			);

			if ( $saved_permalinks !== $permalinks ) {
				update_option( 'attachment_permalink', $permalinks );
			}

			$permalinks['attachment_base'] = untrailingslashit( $permalinks['attachment_base'] );

			return $permalinks;
		} // END aswp_get_permalink_structure()

		/**
		 * Switch Attachment Slug to site language.
		 *
		 * @access public
		 *
		 * @since 2.0.0
		 *
		 * @static
		 */
		public static function aswp_switch_to_site_locale() {
			if ( function_exists( 'switch_to_locale' ) ) {
				switch_to_locale( get_locale() );

				// Filter on plugin_locale so load_plugin_textdomain loads the correct locale.
				add_filter( 'plugin_locale', 'get_locale' );

				// Init Attachment Slug locale.
				self::load_plugin_textdomain();
			}
		} // END aswp_switch_to_site_locale()

		/**
		 * Switch Attachment Slug language to original.
		 *
		 * @access public
		 *
		 * @since 2.0.0
		 *
		 * @static
		 */
		public static function aswp_restore_locale() {
			if ( function_exists( 'restore_previous_locale' ) ) {
				restore_previous_locale();

				// Remove filter.
				remove_filter( 'plugin_locale', 'get_locale' );

				// Init Attachment Slug locale.
				self::load_plugin_textdomain();
			}
		} // END aswp_restore_locale()

	} // END class

} // END if class exists

return Attachment_Slug::instance();