MatthewMi11er/wordpress-plugin-mi11er-utility

<?php
/**
 * Redirect OLD URLs for a particular post.
 *
 * @package Mi11er\Utility
 */

namespace Mi11er\Utility;

use Mi11er\Utility\Template_Tags as TT;

/**
 * This class provides looking up old URLs and redirecting requests for those
 * URLs to the current URL for the associated post.
 *
 * @todo get settings from DB in addtion to using filters.
 * @todo allow deletion
 */
class Redirect implements Plugin_Interface
{
    const META_FIELD  = '_mu_old_url_redirect';
    const META_BOX    = 'mu-old-url-redirect';
    const CACHE_GROUP = 'mu-old-url-redirect';

    /**
     * Run whatever is needed for plugin setup
     */
    public function setup() {
        if ( is_admin() ) {
            // Admin Actions.
            add_action( 'add_meta_boxes',        [ $this, 'add_meta_boxes_action' ],     10, 2 );
        }

        // Actions.
        add_action( 'template_redirect', [ $this, 'template_redirect_action' ], 0, 0 );
    }

    /**
     * Run whatever is needed for plugin activation
     */
    public function activate() {
        return;
    }

    /**
     * ================Actions
     */

    /**
     * Add the OLD URL Meta Box to all post types.
     *
     * @param string  $post_type Post type.
     * @param WP_Post $post      Post object.
     */
    function add_meta_boxes_action( $post_type, $post ) {
        if ( ! empty( get_post_meta( $post->ID, self::META_FIELD, false ) ) ) {
            add_meta_box(
                self::META_BOX,
                __( 'Old URL Redirect', 'mi11er-utility' ),
                [ $this, 'old_url_redirect_meta_box' ],
                $post_type
            );
        }
    }

    /**
     * Call back for the template_redirect action hook.
     * Needs to run early to prevent Wordpresses URL guessing on mangled URLs
     *
     * Determine the orginally requested uri
     * Determine if a new URI exists
     * Redirect to the new URI
     */
    public function template_redirect_action() {
        global $wpdb;

        if ( ! is_404() ) {
            return;
        }

        $request_url = TT::get_the_request_url();
        if ( null === $request_url ) {
            return;
        }

        $request_path = trim( $request_url['path'], '/' ); // Remove leading and trailing slashes.

        $cache_key = md5( $request_path );
        if ( false === $link = wp_cache_get( $cache_key, self::CACHE_GROUP ) ) {
            $id = (int) $wpdb->get_var( $wpdb->prepare(
                "
                    SELECT post_id
                    FROM $wpdb->postmeta
                    WHERE ( meta_key = %s )
                      AND ( meta_value = %s )
                "
                ,self::META_FIELD
                ,$request_path
            )); // WPCS: db call ok.

            if ( $id ) {
                $link = get_permalink( $id );
            }
            wp_cache_set( $cache_key, $link, self::CACHE_GROUP, 5 * MINUTE_IN_SECONDS );
        }

        if ( ! $link ) {
            return;
        }

        // Add back original query string.
        if ( array_key_exists( 'query', $request_url ) ) {
            parse_str( $request_url['query'], $request_query );
            $link = add_query_arg( $request_query, $link );
        }

        wp_redirect( $link, 301 );
        exit;
    }

    /**
     * ================Misc
     */

    /**
     * Display the Old URL Redirect Meta Box
     *
     * @todo allow update?
     *
     * @param \WP_Post $post The post we're working on.
     */
    public function old_url_redirect_meta_box( $post ) {
        ?>
        <ul>
            <?php foreach ( get_post_meta( $post->ID, self::META_FIELD, false ) as $value ) : ?>
                <li><?php echo esc_html( $value ); ?></li>
            <?php endforeach; ?>
        </ul>
        <?php
    }
}