mirror of
https://github.com/Terranom674/Piwigo_Bratonien_Tools.git
synced 2026-09-19 17:34:31 +00:00
NC-Wizard Verzeichnisauswahl und Stammverzeichnis ergaenzen
This commit is contained in:
Terranom674
@@ -6,10 +6,7 @@ if (!defined('PHPWG_ROOT_PATH'))
|
||||
|
||||
function bratonien_tools_nc_wizard_apply_known_database_profile(array &$state)
|
||||
{
|
||||
if (empty($state['scan_ok']) || trim((string)($state['base_url'] ?? '')) === '')
|
||||
{
|
||||
return false;
|
||||
}
|
||||
if (empty($state['scan_ok']) || trim((string)($state['base_url'] ?? '')) === '') return false;
|
||||
|
||||
$base_host = strtolower(trim((string)parse_url((string)$state['base_url'], PHP_URL_HOST)));
|
||||
|
||||
@@ -72,13 +69,60 @@ function bratonien_tools_nc_wizard_apply_known_database_profile(array &$state)
|
||||
$state['storage_candidates'] = $state['storages'];
|
||||
$state['technical_source'] = 'Gespeicherte Reader-Verbindung wird erneut geprüft';
|
||||
$state['technical_error'] = '';
|
||||
|
||||
return true;
|
||||
}
|
||||
|
||||
return false;
|
||||
}
|
||||
|
||||
function bratonien_tools_nc_wizard_prepare_directory_stage(array &$state, array $known_storages)
|
||||
{
|
||||
if ((string)($state['technical_stage'] ?? '') === 'database_details') return;
|
||||
|
||||
$known_by_storage = array();
|
||||
foreach ($known_storages as $known)
|
||||
{
|
||||
$storage_id = trim((string)($known['storage_id'] ?? ''));
|
||||
$mount = rtrim(trim((string)($known['local_mount'] ?? '')), '/');
|
||||
if ($storage_id === '' || $mount === '') continue;
|
||||
if (!isset($known_by_storage[$storage_id])) $known_by_storage[$storage_id] = $known;
|
||||
}
|
||||
|
||||
$candidates = isset($state['storage_candidates']) && is_array($state['storage_candidates']) ? $state['storage_candidates'] : array();
|
||||
$all_mapped = !empty($candidates);
|
||||
|
||||
foreach ($candidates as &$candidate)
|
||||
{
|
||||
$storage_id = trim((string)($candidate['storage_id'] ?? ''));
|
||||
$known = isset($known_by_storage[$storage_id]) ? $known_by_storage[$storage_id] : null;
|
||||
if (is_array($known))
|
||||
{
|
||||
$candidate['source_prefix'] = trim((string)($known['source_prefix'] ?? $candidate['source_prefix'] ?? ''), '/');
|
||||
$candidate['local_mount'] = rtrim(trim((string)($known['local_mount'] ?? '')), '/');
|
||||
}
|
||||
|
||||
$mount = trim((string)($candidate['local_mount'] ?? ''));
|
||||
if ($mount === '' || !is_dir($mount) || !is_readable($mount)) $all_mapped = false;
|
||||
$candidate['include_prefix'] = '';
|
||||
}
|
||||
unset($candidate);
|
||||
|
||||
$state['storage_candidates'] = $candidates;
|
||||
$state['storages'] = array();
|
||||
$state['technical_complete'] = false;
|
||||
$state['technical_stage'] = 'mounts';
|
||||
$state['technical_source'] = $all_mapped
|
||||
? 'Datenzugriff und Speicherzuordnung erkannt; Verzeichnisauswahl offen'
|
||||
: 'Datenzugriff erkannt; Speicherzuordnung muss bestätigt werden';
|
||||
$state['directory_selection_ready'] = $all_mapped;
|
||||
}
|
||||
|
||||
function bratonien_tools_nc_wizard_finish_data_access_for_selection(array &$state, array $known_storages)
|
||||
{
|
||||
bratonien_tools_nc_wizard_finish_data_access($state);
|
||||
bratonien_tools_nc_wizard_prepare_directory_stage($state, $known_storages);
|
||||
}
|
||||
|
||||
function bratonien_tools_nc_wizard_scan_with_known_database()
|
||||
{
|
||||
$state = bratonien_tools_nc_wizard_state();
|
||||
@@ -102,10 +146,8 @@ function bratonien_tools_nc_wizard_scan_with_known_database()
|
||||
{
|
||||
$response = bratonien_tools_nc_wizard_http($candidate_url.'/status.php');
|
||||
if ($response['status'] < 200 || $response['status'] >= 300) continue;
|
||||
|
||||
$candidate_status = json_decode($response['body'], true);
|
||||
if (!is_array($candidate_status) || empty($candidate_status['installed'])) continue;
|
||||
|
||||
$base_url = $candidate_url;
|
||||
$status_data = $candidate_status;
|
||||
break;
|
||||
@@ -123,12 +165,10 @@ function bratonien_tools_nc_wizard_scan_with_known_database()
|
||||
$password,
|
||||
array('OCS-APIRequest: true')
|
||||
);
|
||||
|
||||
if ($user_response['status'] === 401 || $user_response['status'] === 403) throw new RuntimeException('Nextcloud hat Benutzername oder Passwort abgelehnt.');
|
||||
if ($user_response['status'] < 200 || $user_response['status'] >= 300) throw new RuntimeException('Nextcloud ist erreichbar, aber die Anmeldung konnte nicht geprüft werden.');
|
||||
|
||||
$user_data = bratonien_tools_nc_wizard_ocs_data($user_response['body']);
|
||||
|
||||
$users = array();
|
||||
$can_list_users = false;
|
||||
try
|
||||
@@ -139,7 +179,6 @@ function bratonien_tools_nc_wizard_scan_with_known_database()
|
||||
$password,
|
||||
array('OCS-APIRequest: true')
|
||||
);
|
||||
|
||||
if ($users_response['status'] >= 200 && $users_response['status'] < 300)
|
||||
{
|
||||
$users_data = bratonien_tools_nc_wizard_ocs_data($users_response['body']);
|
||||
@@ -174,24 +213,13 @@ function bratonien_tools_nc_wizard_scan_with_known_database()
|
||||
'connection_name'=>$url_host !== '' ? $url_host : 'Nextcloud',
|
||||
'scan_message'=>'Nextcloud wurde erkannt und der Benutzerzugriff wurde bestätigt.',
|
||||
'_password'=>$password,
|
||||
'api_status'=>'pending',
|
||||
'api_username'=>'',
|
||||
'api_error'=>'',
|
||||
'db_host'=>strtolower($url_host),
|
||||
'db_port'=>'5432',
|
||||
'db_database'=>'nextcloud',
|
||||
'db_user'=>'',
|
||||
'db_password_set'=>false,
|
||||
'_db_password'=>'',
|
||||
'source_view'=>'piwigo_showcase_sources',
|
||||
'activity_view'=>'piwigo_showcase_activity',
|
||||
'api_status'=>'pending','api_username'=>'','api_error'=>'',
|
||||
'db_host'=>strtolower($url_host),'db_port'=>'5432','db_database'=>'nextcloud','db_user'=>'','db_password_set'=>false,'_db_password'=>'',
|
||||
'source_view'=>'piwigo_showcase_sources','activity_view'=>'piwigo_showcase_activity',
|
||||
'gallery_root'=>rtrim(PHPWG_ROOT_PATH, '/').'/galleries/nextcloud',
|
||||
'storages'=>array(),
|
||||
'storage_candidates'=>array(),
|
||||
'technical_stage'=>'auto_check',
|
||||
'technical_source'=>'Automatische Prüfung',
|
||||
'technical_error'=>'',
|
||||
'technical_complete'=>false,
|
||||
'storages'=>array(),'storage_candidates'=>array(),
|
||||
'technical_stage'=>'auto_check','technical_source'=>'Automatische Prüfung','technical_error'=>'','technical_complete'=>false,
|
||||
'directory_selection_ready'=>false,
|
||||
));
|
||||
|
||||
if (!bratonien_tools_nc_wizard_apply_known_database_profile($state))
|
||||
@@ -200,13 +228,13 @@ function bratonien_tools_nc_wizard_scan_with_known_database()
|
||||
$state['technical_source'] = 'Keine bekannte Reader-Verbindung gefunden';
|
||||
$state['technical_error'] = 'Für diese Nextcloud ist noch keine bekannte Datenbank-Reader-Verbindung gespeichert. Die Nextcloud-Anmeldedaten werden nicht als PostgreSQL-Zugang verwendet.';
|
||||
bratonien_tools_nc_wizard_store($state);
|
||||
|
||||
return array('message'=>'Nextcloud wurde gefunden. Für den Datenzugriff wird eine separate Reader-Verbindung benötigt.');
|
||||
}
|
||||
|
||||
$known_storages = isset($state['storages']) && is_array($state['storages']) ? $state['storages'] : array();
|
||||
try
|
||||
{
|
||||
bratonien_tools_nc_wizard_finish_data_access($state);
|
||||
bratonien_tools_nc_wizard_finish_data_access_for_selection($state, $known_storages);
|
||||
}
|
||||
catch (Throwable $e)
|
||||
{
|
||||
@@ -214,54 +242,30 @@ function bratonien_tools_nc_wizard_scan_with_known_database()
|
||||
$state['technical_stage'] = 'database_details';
|
||||
$state['technical_error'] = $e->getMessage();
|
||||
}
|
||||
|
||||
bratonien_tools_nc_wizard_store($state);
|
||||
|
||||
if ($state['technical_stage'] === 'database_details')
|
||||
{
|
||||
return array('message'=>'Nextcloud wurde gefunden. Die bekannte Reader-Verbindung konnte noch nicht vollständig bestätigt werden.');
|
||||
}
|
||||
if ($state['technical_stage'] === 'mounts')
|
||||
{
|
||||
return array('message'=>'Nextcloud und Datenzugriff wurden bestätigt. Ein Speicherort muss noch zugeordnet werden.');
|
||||
}
|
||||
|
||||
return array('message'=>'Nextcloud und die gespeicherte Reader-Verbindung wurden erfolgreich bestätigt.');
|
||||
if ($state['technical_stage'] === 'database_details') return array('message'=>'Nextcloud wurde gefunden. Die bekannte Reader-Verbindung konnte noch nicht vollständig bestätigt werden.');
|
||||
return array('message'=>'Nextcloud und Datenzugriff wurden bestätigt. Jetzt können die gewünschten Verzeichnisse gewählt werden.');
|
||||
}
|
||||
|
||||
function bratonien_tools_nc_wizard_save_technical_with_known_database()
|
||||
{
|
||||
$state = bratonien_tools_nc_wizard_state();
|
||||
if (empty($state['scan_ok'])) throw new RuntimeException('Bitte zuerst Nextcloud erfolgreich scannen.');
|
||||
if (trim((string)($state['db_user'] ?? '')) === '' || (string)($state['_db_password'] ?? '') === '') bratonien_tools_nc_wizard_apply_known_database_profile($state);
|
||||
if (trim((string)($state['db_user'] ?? '')) === '' || (string)($state['_db_password'] ?? '') === '') throw new RuntimeException('Für diese Nextcloud sind noch keine Datenbank-Reader-Zugangsdaten bekannt. Nextcloud-Benutzer und -Passwort werden dafür bewusst nicht verwendet.');
|
||||
|
||||
if (trim((string)($state['db_user'] ?? '')) === '' || (string)($state['_db_password'] ?? '') === '')
|
||||
{
|
||||
bratonien_tools_nc_wizard_apply_known_database_profile($state);
|
||||
}
|
||||
|
||||
if (trim((string)($state['db_user'] ?? '')) === '' || (string)($state['_db_password'] ?? '') === '')
|
||||
{
|
||||
throw new RuntimeException('Für diese Nextcloud sind noch keine Datenbank-Reader-Zugangsdaten bekannt. Nextcloud-Benutzer und -Passwort werden dafür bewusst nicht verwendet.');
|
||||
}
|
||||
|
||||
$known_storages = isset($state['storages']) && is_array($state['storages']) ? $state['storages'] : array();
|
||||
$state['db_host'] = trim((string)($_POST['nc_wizard_db_host'] ?? $state['db_host']));
|
||||
$state['db_port'] = (string)max(1, min(65535, (int)($_POST['nc_wizard_db_port'] ?? $state['db_port'])));
|
||||
$state['db_database'] = trim((string)($_POST['nc_wizard_db_database'] ?? $state['db_database']));
|
||||
$state['technical_stage'] = 'database_details';
|
||||
bratonien_tools_nc_wizard_store($state);
|
||||
|
||||
if ($state['db_host'] === '' || $state['db_database'] === '') throw new RuntimeException('Die Adresse der Datenbank ist noch unvollständig.');
|
||||
|
||||
try
|
||||
{
|
||||
bratonien_tools_nc_wizard_finish_data_access($state);
|
||||
bratonien_tools_nc_wizard_finish_data_access_for_selection($state, $known_storages);
|
||||
bratonien_tools_nc_wizard_store($state);
|
||||
|
||||
return array(
|
||||
'message'=>$state['technical_complete']
|
||||
? 'Datenzugriff wurde erfolgreich geprüft.'
|
||||
: 'Datenzugriff funktioniert. Ein Speicherort muss noch bestätigt werden.'
|
||||
);
|
||||
return array('message'=>'Datenzugriff wurde erfolgreich geprüft. Jetzt können die gewünschten Verzeichnisse gewählt werden.');
|
||||
}
|
||||
catch (Throwable $e)
|
||||
{
|
||||
@@ -271,3 +275,174 @@ function bratonien_tools_nc_wizard_save_technical_with_known_database()
|
||||
throw $e;
|
||||
}
|
||||
}
|
||||
|
||||
function bratonien_tools_nc_wizard_directory_options(array $state)
|
||||
{
|
||||
if (empty($state['scan_ok']) || trim((string)($state['db_user'] ?? '')) === '' || (string)($state['_db_password'] ?? '') === '') return array();
|
||||
|
||||
$config = array('host'=>$state['db_host'],'port'=>$state['db_port'],'database'=>$state['db_database'],'user'=>$state['db_user']);
|
||||
$source_view = bratonien_tools_nc_connector_view_name($state['source_view']);
|
||||
$rows = bratonien_tools_nc_connector_psql($config, (string)$state['_db_password'], "SELECT DISTINCT storage_id::text || E'\\t' || COALESCE(source_path, '') FROM ".$source_view." ORDER BY 1");
|
||||
|
||||
$paths = array();
|
||||
foreach (preg_split('/\r\n|\r|\n/', trim($rows)) as $line)
|
||||
{
|
||||
if ($line === '') continue;
|
||||
$parts = explode("\t", $line, 2);
|
||||
if (count($parts) !== 2) continue;
|
||||
$storage_id = trim($parts[0]);
|
||||
$source_path = trim($parts[1], '/');
|
||||
if ($storage_id === '') continue;
|
||||
if (!isset($paths[$storage_id])) $paths[$storage_id] = array();
|
||||
$paths[$storage_id][] = $source_path;
|
||||
}
|
||||
|
||||
$result = array();
|
||||
foreach ((array)($state['storage_candidates'] ?? array()) as $index=>$candidate)
|
||||
{
|
||||
$storage_id = trim((string)($candidate['storage_id'] ?? ''));
|
||||
$mapping_prefix = trim((string)($candidate['source_prefix'] ?? ''), '/');
|
||||
$options = array(''=>'Stammverzeichnis');
|
||||
|
||||
foreach (($paths[$storage_id] ?? array()) as $source_path)
|
||||
{
|
||||
$relative = $source_path;
|
||||
if ($mapping_prefix !== '')
|
||||
{
|
||||
if ($source_path === $mapping_prefix) $relative = '';
|
||||
elseif (strpos($source_path, $mapping_prefix.'/') === 0) $relative = substr($source_path, strlen($mapping_prefix) + 1);
|
||||
else continue;
|
||||
}
|
||||
$relative = trim($relative, '/');
|
||||
if ($relative === '') continue;
|
||||
$segments = explode('/', $relative);
|
||||
$current = '';
|
||||
foreach ($segments as $segment)
|
||||
{
|
||||
if ($segment === '') continue;
|
||||
$current = $current === '' ? $segment : $current.'/'.$segment;
|
||||
$options[$current] = $current;
|
||||
}
|
||||
}
|
||||
|
||||
if (count($options) > 1)
|
||||
{
|
||||
$root = $options[''];
|
||||
unset($options['']);
|
||||
natcasesort($options);
|
||||
$options = array(''=>$root) + $options;
|
||||
}
|
||||
|
||||
$result[] = array(
|
||||
'index'=>(int)$index,
|
||||
'storage_id'=>$storage_id,
|
||||
'mount'=>(string)($candidate['local_mount'] ?? ''),
|
||||
'ready'=>trim((string)($candidate['local_mount'] ?? '')) !== '',
|
||||
'options'=>$options,
|
||||
);
|
||||
}
|
||||
return $result;
|
||||
}
|
||||
|
||||
function bratonien_tools_nc_wizard_save_mounts_with_directories()
|
||||
{
|
||||
$state = bratonien_tools_nc_wizard_state();
|
||||
$candidates = isset($state['storage_candidates']) && is_array($state['storage_candidates']) ? $state['storage_candidates'] : array();
|
||||
if (!$candidates) throw new RuntimeException('Es wurden noch keine Speicherorte erkannt.');
|
||||
|
||||
$mounts = isset($_POST['nc_wizard_storage_mount']) && is_array($_POST['nc_wizard_storage_mount']) ? $_POST['nc_wizard_storage_mount'] : array();
|
||||
$directories = isset($_POST['nc_wizard_directory']) && is_array($_POST['nc_wizard_directory']) ? $_POST['nc_wizard_directory'] : array();
|
||||
$storages = array();
|
||||
|
||||
foreach ($candidates as $index=>$candidate)
|
||||
{
|
||||
$mount = rtrim(trim((string)($candidate['local_mount'] ?? '')), '/');
|
||||
if ($mount === '') $mount = rtrim(trim((string)($mounts[$index] ?? '')), '/');
|
||||
if ($mount === '' || $mount[0] !== '/') throw new RuntimeException('Für einen Speicherort fehlt ein gültiger lokaler Pfad.');
|
||||
if (!is_dir($mount) || !is_readable($mount)) throw new RuntimeException('Der angegebene Speicherort ist nicht vorhanden oder nicht lesbar: '.$mount);
|
||||
|
||||
$selected = isset($directories[$index]) && is_array($directories[$index]) ? $directories[$index] : array();
|
||||
$normalized = array();
|
||||
foreach ($selected as $directory)
|
||||
{
|
||||
$directory = trim((string)$directory, '/');
|
||||
if ($directory === '') continue;
|
||||
if ($directory[0] === '/' || preg_match('#(^|/)\.\.(/|$)#', $directory)) throw new RuntimeException('Ungültige Verzeichnisauswahl.');
|
||||
$normalized[$directory] = true;
|
||||
}
|
||||
if (!$normalized) $normalized[''] = true;
|
||||
|
||||
foreach (array_keys($normalized) as $include_prefix)
|
||||
{
|
||||
$storages[] = array(
|
||||
'storage_id'=>(string)($candidate['storage_id'] ?? ''),
|
||||
'source_prefix'=>trim((string)($candidate['source_prefix'] ?? ''), '/'),
|
||||
'local_mount'=>$mount,
|
||||
'include_prefix'=>$include_prefix,
|
||||
);
|
||||
}
|
||||
}
|
||||
|
||||
$state['storages'] = $storages;
|
||||
$state['technical_complete'] = true;
|
||||
$state['technical_stage'] = 'ready';
|
||||
$state['technical_error'] = '';
|
||||
$state['directory_selection_ready'] = false;
|
||||
bratonien_tools_nc_wizard_store($state);
|
||||
return array('message'=>'Verzeichnisauswahl wurde übernommen.');
|
||||
}
|
||||
|
||||
function bratonien_tools_nc_wizard_finish_with_directories()
|
||||
{
|
||||
$state = bratonien_tools_nc_wizard_state();
|
||||
if ((int)$state['step'] !== 4 || empty($state['technical_complete']) || trim((string)$state['showcase_user']) === '') throw new RuntimeException('Der Assistent ist noch nicht vollständig.');
|
||||
|
||||
if (array_key_exists('nc_wizard_fallback_user', $_POST)) $state['_fallback_user'] = trim((string)$_POST['nc_wizard_fallback_user']);
|
||||
if (array_key_exists('nc_wizard_fallback_password', $_POST)) $state['_fallback_password'] = (string)$_POST['nc_wizard_fallback_password'];
|
||||
bratonien_tools_nc_wizard_store($state);
|
||||
|
||||
$fallback_user = trim((string)$state['_fallback_user']);
|
||||
$fallback_password = (string)$state['_fallback_password'];
|
||||
if (($fallback_user === '') !== ($fallback_password === '')) throw new RuntimeException('Fallback-Benutzer und Fallback-Passwort müssen entweder beide angegeben oder beide leer gelassen werden.');
|
||||
if ($state['api_status'] !== 'ok' && $fallback_user === '') throw new RuntimeException('Da die Piwigo-API übersprungen wurde, ist ein Fallback-Zugang erforderlich.');
|
||||
|
||||
$mapping_lines = array();
|
||||
foreach ((array)$state['storages'] as $storage)
|
||||
{
|
||||
$key = (string)$storage['storage_id'].'|'.trim((string)$storage['source_prefix'], '/').'|'.(string)$storage['local_mount'];
|
||||
$mapping_lines[$key] = (string)$storage['storage_id'].' | '.trim((string)$storage['source_prefix'], '/').' | '.(string)$storage['local_mount'];
|
||||
}
|
||||
|
||||
$_POST['nc_name']=(string)$state['connection_name'];$_POST['nc_host']=(string)$state['db_host'];$_POST['nc_port']=(string)$state['db_port'];$_POST['nc_database']=(string)$state['db_database'];$_POST['nc_user']=(string)$state['db_user'];$_POST['nc_db_password']=(string)$state['_db_password'];
|
||||
$_POST['nc_source_view']=(string)$state['source_view'];$_POST['nc_activity_view']=(string)$state['activity_view'];$_POST['nc_gallery_root']=(string)$state['gallery_root'];$_POST['nc_storages']=implode("\n",array_values($mapping_lines));
|
||||
$_POST['nc_quiet_seconds']='120';$_POST['nc_max_wait_seconds']='900';$_POST['nc_full_sync_seconds']='86400';$_POST['nc_piwigo_user']=$fallback_user;$_POST['nc_piwigo_password']=$fallback_password;
|
||||
$_POST['nc_nextcloud_url']=(string)$state['base_url'];$_POST['nc_showcase_user']=(string)$state['showcase_user'];$_POST['nc_access_user']=(string)$state['username'];$_POST['nc_product']=(string)$state['product'];$_POST['nc_version']=(string)$state['version'];$_POST['nc_api_validated']=$state['api_status']==='ok'?'1':'0';
|
||||
|
||||
$result = bratonien_tools_nc_connector_create_local_api_first();
|
||||
$connection_id = (int)($result['connection_id'] ?? 0);
|
||||
if ($connection_id < 1) throw new RuntimeException('Die neue Verbindung konnte nicht gespeichert werden.');
|
||||
|
||||
$connection = bratonien_tools_nc_connector_connection($connection_id, false);
|
||||
if (!$connection) throw new RuntimeException('Die neue Verbindung konnte nach dem Anlegen nicht gelesen werden.');
|
||||
$config = $connection['config'];
|
||||
$config['storages'] = array_values($state['storages']);
|
||||
$config_json = json_encode($config, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
|
||||
if (!is_string($config_json)) throw new RuntimeException('Die Verzeichnisauswahl konnte nicht serialisiert werden.');
|
||||
$table = bratonien_tools_nc_connector_table();
|
||||
pwg_query("UPDATE `$table` SET config_json='".pwg_db_real_escape_string($config_json)."' WHERE id=".$connection_id." LIMIT 1");
|
||||
|
||||
try
|
||||
{
|
||||
if ($state['api_status'] === 'ok') bratonien_tools_nc_api_credentials_store((string)$state['_api_key_id'], (string)$state['_api_key_secret']);
|
||||
}
|
||||
catch (Throwable $e)
|
||||
{
|
||||
pwg_query("DELETE FROM `$table` WHERE id=".$connection_id." LIMIT 1");
|
||||
throw new RuntimeException('Die Verbindung wurde nicht übernommen, weil der geprüfte API-Zugang nicht gespeichert werden konnte: '.$e->getMessage());
|
||||
}
|
||||
|
||||
unset($_SESSION['bratonien_nc_wizard']);
|
||||
unset($result['connection_id']);
|
||||
$result['message'] = 'Verbindung wurde vollständig durch den Assistenten angelegt. '.$result['message'];
|
||||
return $result;
|
||||
}
|
||||
|
||||
Reference in New Issue
Block a user