<?php
/**
* Abstracts session data access using WP_Session_Tokens
*/
class Loco_data_Session extends Loco_data_Serializable {
/**
* @var Loco_data_Session
*/
private static $current;
/**
* Value from wp_get_session_token
* @var string
*/
private $token;
/**
* @var WP_User_Meta_Session_Tokens
*/
private $manager;
/**
* Dirty flag: TODO abstract into array access setters
* @var bool
*/
private $dirty = false;
/**
* @return Loco_data_Session
*/
public static function get(){
if( ! self::$current ){
new Loco_data_Session;
}
return self::$current;
}
/**
* Trash data and remove from memory
*/
public static function destroy(){
if( self::$current ){
try {
self::$current->clear();
}
catch( Exception $e ){
// probably no session to destroy
}
self::$current = null;
}
}
/**
* Commit current session data to WordPress storage and remove from memory
*/
public static function close(){
if( self::$current && self::$current->dirty ){
self::$current->persist();
self::$current = null;
}
}
/**
* @internal
*/
final public function __construct( array $raw = [] ){
$this->token = wp_get_session_token();
if( ! $this->token ){
throw new Loco_error_Exception('Failed to get session token');
}
parent::__construct( [] );
$this->manager = WP_Session_Tokens::get_instance( get_current_user_id() );
// populate object from stored session data
$data = $this->getRaw();
if( isset($data['loco']) ){
$this->setUnserialized( $data['loco'] );
}
// any initial arbitrary data can be merged on top
foreach( $raw as $prop => $value ){
$this[$prop] = $value;
}
// enforce single instance
self::$current = $this;
// ensure against unclean shutdown
if( loco_debugging() ){
register_shutdown_function( [$this,'_on_shutdown'] );
}
}
/**
* @internal
* Ensure against unclean use of session storage
*/
public function _on_shutdown(){
if( $this->dirty ){
trigger_error('Unclean session shutdown: call either Loco_data_Session::destroy or Loco_data_Session::close');
}
}
/**
* Get raw session data held by WordPress
* @return array
*/
private function getRaw(){
$data = $this->manager->get( $this->token );
// session data will exist if WordPress login is valid
if( ! $data || ! is_array($data) ){
throw new Loco_error_Exception('Invalid session');
}
return $data;
}
/**
* Persist object in WordPress usermeta table
* @return Loco_data_Session
*/
public function persist(){
$data = $this->getRaw();
$data['loco'] = $this->getSerializable();
$this->manager->update( $this->token, $data );
$this->dirty = false;
return $this;
}
/**
* Clear object data and remove our key from WordPress usermeta record
* @return Loco_data_Session
*/
public function clear(){
$data = $this->getRaw();
if( isset($data['loco']) ){
unset( $data['loco'] );
$this->manager->update( $this->token, $data );
}
$this->exchangeArray( [] );
$this->dirty = false;
return $this;
}
/**
* @param string name of messages bag, e.g. "errors"
* @param string optionally put message in rather than getting data out
* @return mixed
*/
public function flash( $bag, $data = null ){
if( isset($data) ){
$this->dirty = true;
$this[$bag][] = $data;
}
// else get first object in bag and remove before returning
else if( isset($this[$bag]) ){
if( $data = array_shift($this[$bag]) ){
$this->dirty = true;
return $data;
}
}
return null;
}
/**
* {@inheritDoc}
*/
public function offsetSet( $index, $newval ){
if( ! isset($this[$index]) || $newval !== $this[$index] ){
$this->dirty = true;
parent::offsetSet( $index, $newval );
}
}
/**
* {@inheritDoc}
*/
public function offsetUnset( $index ){
if( isset($this[$index]) ){
$this->dirty = true;
parent::offsetUnset( $index );
}
}
}