Issues with PHP classes and WordPress

Question

I am currently trying to add new options to the Rename wp-login.php because it is barely being updated. The owner also allowed me to add new options to it.

The plugin functionality allows you to 'rename' /wp-admin/ and wp-login.php to a different location. I barely have any knowledge about PHP classes and, you guessed it, the whole plugin is basically created using PHP classes.

What I am trying to do:

1. When the field is empty, revert everything to /wp-admin/. Basically a disable option; I've got that, but when the field is left blank and you'll save it, it saves the value which was entered before. That's a problem; It should be empty when you save it blank.

2. Currently the field is in the "Permalinks" section of the settings menu, but I want to put the option in a custom page.

Also, how does this plugin saves the value of the field? I can't find anything, not even a register_setting function.

When I say 'the field', I'm talking about this field: <input id="rwl-page-input" type="text" name="rwl_page" value="' . $this->new_login_slug() . '">

---

Code is as follows:

<?php
if ( defined( 'ABSPATH' ) && ! class_exists( 'Rename_WP_Login' ) ) {

    class Rename_WP_Login {
        private $wp_login_php;

        private function basename() {
            return plugin_basename( __FILE__ );
        }

        private function path() {
            return trailingslashit( dirname( __FILE__ ) );
        }

        private function use_trailing_slashes() {
            return '/' === substr( get_option( 'permalink_structure' ), -1, 1 );
        }

        private function user_trailingslashit( $string ) {
            return $this->use_trailing_slashes() ? trailingslashit( $string ) : untrailingslashit( $string );
        }

        private function wp_template_loader() {
            global $pagenow;

            $pagenow = 'index.php';

            if ( ! defined( 'WP_USE_THEMES' ) ) {
                define( 'WP_USE_THEMES', true );
            }

            wp();

            if ( $_SERVER['REQUEST_URI'] === $this->user_trailingslashit( str_repeat( '-/', 10 ) ) ) {
                $_SERVER['REQUEST_URI'] = $this->user_trailingslashit( '/wp-login-php/' );
            }

            require_once ABSPATH . WPINC . '/template-loader.php';

            die;
        }

        private function new_login_slug() {
            if (
                ( $slug = get_option( 'rwl_page' ) ) || (
                    is_multisite() &&
                    is_plugin_active_for_network( $this->basename() ) &&
                    ( $slug = get_site_option( 'rwl_page', 'login' ) )
                ) ||
                ( $slug = 'login' )
            ) {
                return $slug;
            }
        }

        public function new_login_url( $scheme = null ) {
            if ( get_option( 'permalink_structure' ) ) {
                return $this->user_trailingslashit( home_url( '/', $scheme ) . $this->new_login_slug() );
            } else {
                return home_url( '/', $scheme ) . '?' . $this->new_login_slug();
            }
        }

        public function __construct() {
            register_activation_hook( $this->basename(), array( $this, 'activate' ) );
            register_uninstall_hook( $this->basename(), array( 'Rename_WP_Login', 'uninstall' ) );

            add_action( 'admin_init', array( $this, 'admin_init' ) );
            add_action( 'admin_notices', array( $this, 'admin_notices' ) );
            add_action( 'network_admin_notices', array( $this, 'admin_notices' ) );

            if ( is_multisite() && ! function_exists( 'is_plugin_active_for_network' ) ) {
                require_once ABSPATH . '/wp-admin/includes/plugin.php';
            }

            add_filter( 'plugin_action_links_' . $this->basename(), array( $this, 'plugin_action_links' ) );

            if ( is_multisite() && is_plugin_active_for_network( $this->basename() ) ) {
                add_filter( 'network_admin_plugin_action_links_' . $this->basename(), array( $this, 'plugin_action_links' ) );

                add_action( 'wpmu_options', array( $this, 'wpmu_options' ) );
                add_action( 'update_wpmu_options', array( $this, 'update_wpmu_options' ) );
            }

            add_action( 'plugins_loaded', array( $this, 'plugins_loaded' ), 1 );
            add_action( 'wp_loaded', array( $this, 'wp_loaded' ) );

            add_filter( 'site_url', array( $this, 'site_url' ), 10, 4 );
            add_filter( 'network_site_url', array( $this, 'network_site_url' ), 10, 3 );
            add_filter( 'wp_redirect', array( $this, 'wp_redirect' ), 10, 2 );

            add_filter( 'site_option_welcome_email', array( $this, 'welcome_email' ) );

            remove_action( 'template_redirect', 'wp_redirect_admin_locations', 1000 );
        }

        public function activate() {
            add_option( 'rwl_redirect', '1' );
        }

        public static function uninstall() {
            global $wpdb;

            if ( is_multisite() ) {
                $blogs = $wpdb->get_col( "SELECT blog_id FROM {$wpdb->blogs}" );

                if ( $blogs ) {
                    foreach ( $blogs as $blog ) {
                        switch_to_blog( $blog );
                        delete_option( 'rwl_page' );
                    }

                    restore_current_blog();
                }

                delete_site_option( 'rwl_page' );
            } else {
                delete_option( 'rwl_page' );
            }
        }

        public function wpmu_options() {
            echo (
                '<h3>' .
                    _x( 'Rename wp-login.php', 'Text string for settings page', 'rename-wp-login' ) .
                '</h3>' .
                '<p>' .
                    __( 'This option allows you to set a networkwide default, which can be overridden by individual sites. Simply go to to the site’s permalink settings to change the url.', 'rename-wp-login' ) .
                '</p>' .
                '<table class="form-table">' .
                    '<tr valign="top">' .
                        '<th scope="row">' .
                            __( 'Networkwide default', 'rename-wp-login' ) .
                        '</th>' .
                        '<td>' .
                            '<input id="rwl-page-input" type="text" name="rwl_page" value="' . get_site_option( 'rwl_page', 'login' )  . '">' .
                        '</td>' .
                    '</tr>' .
                '</table>'
            );
        }

        public function update_wpmu_options() {
            if (
                ( $rwl_page = sanitize_title_with_dashes( $_POST['rwl_page'] ) ) &&
                strpos( $rwl_page, 'wp-login' ) === false &&
                ! in_array( $rwl_page, $this->forbidden_slugs() )
            ) {
                update_site_option( 'rwl_page', $rwl_page );
            }
        }

        public function admin_init() {
            global $pagenow;

            add_settings_section(
                'rename-wp-login-section',
                _x( 'Rename wp-login.php', 'Text string for settings page', 'rename-wp-login' ),
                array( $this, 'rwl_section_desc' ),
                'permalink'
            );

            add_settings_field(
                'rwl-page',
                '<label for="rwl-page">' . __( 'Login url', 'rename-wp-login' ) . '</label>',
                array( $this, 'rwl_page_input' ),
                'permalink',
                'rename-wp-login-section'
            );

            if ( isset( $_POST['rwl_page'] ) && $pagenow === 'options-permalink.php' ) {
                if (
                    ( $rwl_page = sanitize_title_with_dashes( $_POST['rwl_page'] ) ) &&
                    strpos( $rwl_page, 'wp-login' ) === false &&
                    ! in_array( $rwl_page, $this->forbidden_slugs() )
                ) {
                    if ( is_multisite() && $rwl_page === get_site_option( 'rwl_page', 'login' ) ) {
                        delete_option( 'rwl_page' );
                    } else {
                        update_option( 'rwl_page', $rwl_page );
                    }
                }
            }

            if ( get_option( 'rwl_redirect' ) ) {
                delete_option( 'rwl_redirect' );

                if ( is_multisite() && is_super_admin() && is_plugin_active_for_network( $this->basename() ) ) {
                    $redirect = network_admin_url( 'settings.php#rwl-page-input' );
                } else {
                    $redirect = admin_url( 'options-permalink.php#rwl-page-input' );
                }

                wp_safe_redirect( $redirect );

                die;
            }
        }

        public function rwl_section_desc() {
            if ( is_multisite() && is_super_admin() && is_plugin_active_for_network( $this->basename() ) ) {
                echo (
                    '<p>' .
                        sprintf(
                            __( 'To set a networkwide default, go to %s.', 'rename-wp-login' ),
                            '<a href="' . esc_url( network_admin_url( 'settings.php#rwl-page-input' ) ) . '">' .
                                __( 'Network Settings', 'rename-wp-login' ) .
                            '</a>'
                        ) .
                    '</p>'
                );
            }
        }

        public function rwl_page_input() {
            if ( get_option( 'permalink_structure' ) ) {
                echo '<code>' . trailingslashit( home_url() ) . '</code> <input id="rwl-page-input" type="text" name="rwl_page" value="' . $this->new_login_slug()  . '">' . ( $this->use_trailing_slashes() ? ' <code>/</code>' : '' );
            } else {
                echo '<code>' . trailingslashit( home_url() ) . '?</code> <input id="rwl-page-input" type="text" name="rwl_page" value="' . $this->new_login_slug()  . '">';
            }
        }

        public function admin_notices() {
            global $pagenow;

            if ( ! is_network_admin() && $pagenow === 'options-permalink.php' && isset( $_GET['settings-updated'] ) ) {
                echo '<div class="notice notice-success is-dismissible"><p>' . sprintf( __( 'Your login page is now here: %s. Bookmark this page!', 'rename-wp-login' ), '<strong><a href="' . $this->new_login_url() . '">' . $this->new_login_url() . '</a></strong>' ) . '</p></div>';
            }
        }

        public function plugin_action_links( $links ) {
            if ( is_network_admin() && is_plugin_active_for_network( $this->basename() ) ) {
                array_unshift( $links,
                    '<a href="' . esc_url( network_admin_url( 'settings.php#rwl-page-input' ) ) . '">' .
                        __( 'Settings', 'rename-wp-login' ) .
                    '</a>'
                );
            } elseif ( ! is_network_admin() ) {
                array_unshift( $links,
                    '<a href="' . esc_url( admin_url( 'options-permalink.php#rwl-page-input' ) ) . '">' .
                        __( 'Settings', 'rename-wp-login' ) .
                    '</a>'
                );
            }

            return $links;
        }

        public function plugins_loaded() {
            global $pagenow;

            load_plugin_textdomain( 'rename-wp-login' );

            if (
                ! is_multisite() && (
                    strpos( $_SERVER['REQUEST_URI'], 'wp-signup' ) !== false ||
                    strpos( $_SERVER['REQUEST_URI'], 'wp-activate' ) !== false
                )
            ) {
                wp_die( __( 'This feature is not enabled.', 'rename-wp-login' ), '', array( 'response' => 403 ) );
            }

            $request = parse_url( $_SERVER['REQUEST_URI'] );

            if ( (
                    strpos( $_SERVER['REQUEST_URI'], 'wp-login.php' ) !== false ||
                    untrailingslashit( $request['path'] ) === site_url( 'wp-login', 'relative' )
                ) &&
                ! is_admin()
            ) {
                $this->wp_login_php = true;
                $_SERVER['REQUEST_URI'] = $this->user_trailingslashit( '/' . str_repeat( '-/', 10 ) );
                $pagenow = 'index.php';
            } elseif (
                untrailingslashit( $request['path'] ) === home_url( $this->new_login_slug(), 'relative' ) || (
                    ! get_option( 'permalink_structure' ) &&
                    isset( $_GET[$this->new_login_slug()] ) &&
                    empty( $_GET[$this->new_login_slug()] )
            ) ) {
                $pagenow = 'wp-login.php';
            }
        }

        public function wp_loaded() {
            global $pagenow;

            if ( is_admin() && ! is_user_logged_in() && ! defined( 'DOING_AJAX' ) ) {
                wp_die( __( 'You must log in to access the admin area.', 'rename-wp-login' ), '', array( 'response' => 403 ) );
            }

            $request = parse_url( $_SERVER['REQUEST_URI'] );

            if (
                $pagenow === 'wp-login.php' &&
                $request['path'] !== $this->user_trailingslashit( $request['path'] ) &&
                get_option( 'permalink_structure' )
            ) {
                wp_safe_redirect( $this->user_trailingslashit( $this->new_login_url() ) . ( ! empty( $_SERVER['QUERY_STRING'] ) ? '?' . $_SERVER['QUERY_STRING'] : '' ) );
                die;
            } elseif ( $this->wp_login_php ) {
                if (
                    ( $referer = wp_get_referer() ) &&
                    strpos( $referer, 'wp-activate.php' ) !== false &&
                    ( $referer = parse_url( $referer ) ) &&
                    ! empty( $referer['query'] )
                ) {
                    parse_str( $referer['query'], $referer );

                    if (
                        ! empty( $referer['key'] ) &&
                        ( $result = wpmu_activate_signup( $referer['key'] ) ) &&
                        is_wp_error( $result ) && (
                            $result->get_error_code() === 'already_active' ||
                            $result->get_error_code() === 'blog_taken'
                    ) ) {
                        wp_safe_redirect( $this->new_login_url() . ( ! empty( $_SERVER['QUERY_STRING'] ) ? '?' . $_SERVER['QUERY_STRING'] : '' ) );
                        die;
                    }
                }

                $this->wp_template_loader();
            } elseif ( $pagenow === 'wp-login.php' ) {
                global $error, $interim_login, $action, $user_login;

                @require_once ABSPATH . 'wp-login.php';

                die;
            }
        }

        public function site_url( $url, $path, $scheme, $blog_id ) {
            return $this->filter_wp_login_php( $url, $scheme );
        }

        public function network_site_url( $url, $path, $scheme ) {
            return $this->filter_wp_login_php( $url, $scheme );
        }

        public function wp_redirect( $location, $status ) {
            return $this->filter_wp_login_php( $location );
        }

        public function filter_wp_login_php( $url, $scheme = null ) {
            if ( strpos( $url, 'wp-login.php' ) !== false ) {
                if ( is_ssl() ) {
                    $scheme = 'https';
                }

                $args = explode( '?', $url );

                if ( isset( $args[1] ) ) {
                    parse_str( $args[1], $args );
                    $url = add_query_arg( $args, $this->new_login_url( $scheme ) );
                } else {
                    $url = $this->new_login_url( $scheme );
                }
            }

            return $url;
        }

        public function welcome_email( $value ) {
            return str_replace( 'wp-login.php', trailingslashit( get_site_option( 'rwl_page', 'login' ) ), $value );
        }

        public function forbidden_slugs() {
            $wp = new WP;
            return array_merge( $wp->public_query_vars, $wp->private_query_vars );
        }
    }

    new Rename_WP_Login;
}

I would really, really appreciate it if anyone can help me out with this!

Answer 1

The first

Also, how does this plugin saves the value of the field? I can't find anything, not even a register_setting function.

This plugin save the value by this function:

public function update_wpmu_options() {
    if (
        ( $rwl_page = sanitize_title_with_dashes( $_POST['rwl_page'] ) ) &&
    strpos( $rwl_page, 'wp-login' ) === false &&
        ! in_array( $rwl_page, $this->forbidden_slugs() )
    ) {
        update_site_option( 'rwl_page', $rwl_page );
    }
}

You can read more at: update_site_option

In admin_init function have

add_settings_field(
    'rwl-page',
    '<label for="rwl-page">' . __( 'Login url', 'rename-wp-login' ) . '</label>',
    array( $this, 'rwl_page_input' ),
    'permalink',
    'rename-wp-login-section'
);

This function will get value saved. If you let the field blank this value won't be update. That's why you got old value of it. If you want revert all to old version you can remove this plugin.

Hope it can help. I'm just coder had try this plugin not dev it. xD