/httpdocs/wp-content/plugins/download-manager/libs/class.AssetManager.php:246

I’m not sure when, but I’ve started getting some fatal errors with the Download Manager plugin which were completely blocking my website.

I got my website at least running again by making a change in /httpdocs/wp-content/plugins/download-manager/libs/class.AssetManager.php:246 after examining my error logs.

I’m using PHP 8.0.5 and WPDM 3.1.27 .

The error in my logs is: child 3917085 said into stderr: "NOTICE: PHP message: PHP Fatal error: Uncaught TypeError: array_diff(): Argument #1 ($array) must be of type array, bool given in /var/www/vhosts/mywebsite.com/httpdocs/wp-content/plugins/download-manager/libs/class.AssetManager.php:246"

    function scanDir()
    {
        if (!isset($_REQUEST['__wpdm_scandir']) || !wp_verify_nonce($_REQUEST['__wpdm_scandir'], NONCE_KEY)) wp_send_json(array('success' => false, 'message' => __("Error! Session Expired. Try refreshing page.", "download-manager")));
        check_ajax_referer(NONCE_KEY, '__wpdm_scandir');
        if (!current_user_can('access_server_browser')) wp_send_json(array('success' => false, 'message' => __("Error! Unauthorized access.", "download-manager")));
        global $current_user;
        $root = AssetManager::root();
        $relpath = Crypt::decrypt(wpdm_query_var('path'));
        $path = AssetManager::root($relpath);
        if (!$path) wp_send_json(array('success' => false, 'message' => __("Error! Unauthorized Path.", "download-manager")));
            $items = scandir($path, SCANDIR_SORT_ASCENDING);
            $items = array_diff($items, array('.', '..'));
            $_items = array();
            $_dirs = array();
            Session::set('working_dir', $path);
            foreach ($items as $item) {

                $item_label = $item;
                $item_label = esc_attr($item_label);
                //$item_label = strlen($item_label) > 30 ? substr($item_label, 0, 15) . "..." . substr($item_label, strlen($item_label) - 15) : $item_label;
                $ext = explode('.', $item);
                $ext = end($ext);
                $icon = \WPDM\libs\FileSystem::fileTypeIcon($ext);
                $type = is_dir($path . $item) ? 'dir' : 'file';
                $note = is_dir($path . $item) ? (count(scandir($path . $item)) - 2) . ' items' : number_format((filesize($path . $item) / 1024), 2) . ' KB';
                $rpath = str_replace($root, "", $path . $item);
                $wp_rel_path = str_replace(UPLOAD_DIR, '', $path . $item);
                $wp_rel_path = str_replace(ABSPATH, '', $wp_rel_path);
                $_rpath = Crypt::encrypt($rpath);
                if ($type === 'dir') {
                    $_dirs[] = array('item_label' => $item_label, 'item' => $item, 'icon' => $icon, 'type' => $type, 'note' => $note, 'path' => $_rpath, 'id' => md5($rpath));
                } else {
                    $contenttype = function_exists('mime_content_type') ? mime_content_type($path . $item) : self::mimeType($item);
                    $_items[] = array('item_label' => $item_label, 'item' => $item, 'icon' => $icon, 'type' => $type, 'contenttype' => $contenttype, 'note' => $note, 'path_on' => $path . $item, 'wp_rel_path' => $wp_rel_path, 'path' => $_rpath, 'id' => md5($rpath));
                }

            }

            $allitems = $_dirs;
            foreach ($_items as $_item) {
                $allitems[] = $_item;
            }
            $parts = explode("/", $relpath);
            $breadcrumb[] = "<i class='fa fa-hdd color-purple'></i><a href='#' class='media-folder' data-path=''>" . __("Home", "download-manager") . "</a>";
            $topath = array();
            foreach ($parts as $part) {
                $topath[] = $part;
                $rpath = Crypt::encrypt(implode("/", $topath));
                $breadcrumb[] = "<a href='#' class='media-folder' data-path='{$rpath}'>" . esc_attr($part) . "</a>";
            }
            $breadcrumb = implode("<i class='fa fa-folder-open'></i>", $breadcrumb);
        if ((int)wpdm_query_var('dirs') === 1)
            wp_send_json($_dirs);
        else
            wp_send_json(array('success' => true, 'items' => $allitems, 'breadcrumb' => $breadcrumb, 'root' => $root, WPDM_ADMIN_CAP => current_user_can(WPDM_ADMIN_CAP), 'roles' => $current_user->roles));
        die();
    }

I added an else condition after if (!path):

    function scanDir()
    {
        if (!isset($_REQUEST['__wpdm_scandir']) || !wp_verify_nonce($_REQUEST['__wpdm_scandir'], NONCE_KEY)) wp_send_json(array('success' => false, 'message' => __("Error! Session Expired. Try refreshing page.", "download-manager")));
        check_ajax_referer(NONCE_KEY, '__wpdm_scandir');
        if (!current_user_can('access_server_browser')) wp_send_json(array('success' => false, 'message' => __("Error! Unauthorized access.", "download-manager")));
        global $current_user;
        $root = AssetManager::root();
        $relpath = Crypt::decrypt(wpdm_query_var('path'));
        $path = AssetManager::root($relpath);
        if (!$path) { 
            wp_send_json(array('success' => false, 'message' => __("Error! Unauthorized Path.", "download-manager"))); 
        }
        else {
            $items = scandir($path, SCANDIR_SORT_ASCENDING);
            $items = array_diff($items, array('.', '..'));
            $_items = array();
            $_dirs = array();
            Session::set('working_dir', $path);
            foreach ($items as $item) {

                $item_label = $item;
                $item_label = esc_attr($item_label);
                //$item_label = strlen($item_label) > 30 ? substr($item_label, 0, 15) . "..." . substr($item_label, strlen($item_label) - 15) : $item_label;
                $ext = explode('.', $item);
                $ext = end($ext);
                $icon = \WPDM\libs\FileSystem::fileTypeIcon($ext);
                $type = is_dir($path . $item) ? 'dir' : 'file';
                $note = is_dir($path . $item) ? (count(scandir($path . $item)) - 2) . ' items' : number_format((filesize($path . $item) / 1024), 2) . ' KB';
                $rpath = str_replace($root, "", $path . $item);
                $wp_rel_path = str_replace(UPLOAD_DIR, '', $path . $item);
                $wp_rel_path = str_replace(ABSPATH, '', $wp_rel_path);
                $_rpath = Crypt::encrypt($rpath);
                if ($type === 'dir') {
                    $_dirs[] = array('item_label' => $item_label, 'item' => $item, 'icon' => $icon, 'type' => $type, 'note' => $note, 'path' => $_rpath, 'id' => md5($rpath));
                } else {
                    $contenttype = function_exists('mime_content_type') ? mime_content_type($path . $item) : self::mimeType($item);
                    $_items[] = array('item_label' => $item_label, 'item' => $item, 'icon' => $icon, 'type' => $type, 'contenttype' => $contenttype, 'note' => $note, 'path_on' => $path . $item, 'wp_rel_path' => $wp_rel_path, 'path' => $_rpath, 'id' => md5($rpath));
                }

            }

            $allitems = $_dirs;
            foreach ($_items as $_item) {
                $allitems[] = $_item;
            }
            $parts = explode("/", $relpath);
            $breadcrumb[] = "<i class='fa fa-hdd color-purple'></i><a href='#' class='media-folder' data-path=''>" . __("Home", "download-manager") . "</a>";
            $topath = array();
            foreach ($parts as $part) {
                $topath[] = $part;
                $rpath = Crypt::encrypt(implode("/", $topath));
                $breadcrumb[] = "<a href='#' class='media-folder' data-path='{$rpath}'>" . esc_attr($part) . "</a>";
            }
            $breadcrumb = implode("<i class='fa fa-folder-open'></i>", $breadcrumb);
        }
        if ((int)wpdm_query_var('dirs') === 1)
            wp_send_json($_dirs);
        else
            wp_send_json(array('success' => true, 'items' => $allitems, 'breadcrumb' => $breadcrumb, 'root' => $root, WPDM_ADMIN_CAP => current_user_can(WPDM_ADMIN_CAP), 'roles' => $current_user->roles));
        die();
    }

I have open_basedir restrictions in place, so the wordpress websites can only access their own spaces under httpdocs.