annotate vendor/symfony/http-foundation/Session/Storage/Handler/PdoSessionHandler.php @ 19:fa3358dc1485 tip

Add ndrum files
author Chris Cannam
date Wed, 28 Aug 2019 13:14:47 +0100
parents 129ea1e6d783
children
rev   line source
Chris@0 1 <?php
Chris@0 2
Chris@0 3 /*
Chris@0 4 * This file is part of the Symfony package.
Chris@0 5 *
Chris@0 6 * (c) Fabien Potencier <fabien@symfony.com>
Chris@0 7 *
Chris@0 8 * For the full copyright and license information, please view the LICENSE
Chris@0 9 * file that was distributed with this source code.
Chris@0 10 */
Chris@0 11
Chris@0 12 namespace Symfony\Component\HttpFoundation\Session\Storage\Handler;
Chris@0 13
Chris@0 14 /**
Chris@0 15 * Session handler using a PDO connection to read and write data.
Chris@0 16 *
Chris@0 17 * It works with MySQL, PostgreSQL, Oracle, SQL Server and SQLite and implements
Chris@0 18 * different locking strategies to handle concurrent access to the same session.
Chris@0 19 * Locking is necessary to prevent loss of data due to race conditions and to keep
Chris@0 20 * the session data consistent between read() and write(). With locking, requests
Chris@0 21 * for the same session will wait until the other one finished writing. For this
Chris@0 22 * reason it's best practice to close a session as early as possible to improve
Chris@0 23 * concurrency. PHPs internal files session handler also implements locking.
Chris@0 24 *
Chris@0 25 * Attention: Since SQLite does not support row level locks but locks the whole database,
Chris@0 26 * it means only one session can be accessed at a time. Even different sessions would wait
Chris@0 27 * for another to finish. So saving session in SQLite should only be considered for
Chris@0 28 * development or prototypes.
Chris@0 29 *
Chris@0 30 * Session data is a binary string that can contain non-printable characters like the null byte.
Chris@0 31 * For this reason it must be saved in a binary column in the database like BLOB in MySQL.
Chris@0 32 * Saving it in a character column could corrupt the data. You can use createTable()
Chris@0 33 * to initialize a correctly defined table.
Chris@0 34 *
Chris@0 35 * @see http://php.net/sessionhandlerinterface
Chris@0 36 *
Chris@0 37 * @author Fabien Potencier <fabien@symfony.com>
Chris@0 38 * @author Michael Williams <michael.williams@funsational.com>
Chris@0 39 * @author Tobias Schultze <http://tobion.de>
Chris@0 40 */
Chris@14 41 class PdoSessionHandler extends AbstractSessionHandler
Chris@0 42 {
Chris@0 43 /**
Chris@0 44 * No locking is done. This means sessions are prone to loss of data due to
Chris@0 45 * race conditions of concurrent requests to the same session. The last session
Chris@0 46 * write will win in this case. It might be useful when you implement your own
Chris@0 47 * logic to deal with this like an optimistic approach.
Chris@0 48 */
Chris@0 49 const LOCK_NONE = 0;
Chris@0 50
Chris@0 51 /**
Chris@0 52 * Creates an application-level lock on a session. The disadvantage is that the
Chris@0 53 * lock is not enforced by the database and thus other, unaware parts of the
Chris@0 54 * application could still concurrently modify the session. The advantage is it
Chris@0 55 * does not require a transaction.
Chris@0 56 * This mode is not available for SQLite and not yet implemented for oci and sqlsrv.
Chris@0 57 */
Chris@0 58 const LOCK_ADVISORY = 1;
Chris@0 59
Chris@0 60 /**
Chris@0 61 * Issues a real row lock. Since it uses a transaction between opening and
Chris@0 62 * closing a session, you have to be careful when you use same database connection
Chris@0 63 * that you also use for your application logic. This mode is the default because
Chris@0 64 * it's the only reliable solution across DBMSs.
Chris@0 65 */
Chris@0 66 const LOCK_TRANSACTIONAL = 2;
Chris@0 67
Chris@0 68 /**
Chris@0 69 * @var \PDO|null PDO instance or null when not connected yet
Chris@0 70 */
Chris@0 71 private $pdo;
Chris@0 72
Chris@0 73 /**
Chris@17 74 * @var string|false|null DSN string or null for session.save_path or false when lazy connection disabled
Chris@0 75 */
Chris@0 76 private $dsn = false;
Chris@0 77
Chris@0 78 /**
Chris@0 79 * @var string Database driver
Chris@0 80 */
Chris@0 81 private $driver;
Chris@0 82
Chris@0 83 /**
Chris@0 84 * @var string Table name
Chris@0 85 */
Chris@0 86 private $table = 'sessions';
Chris@0 87
Chris@0 88 /**
Chris@0 89 * @var string Column for session id
Chris@0 90 */
Chris@0 91 private $idCol = 'sess_id';
Chris@0 92
Chris@0 93 /**
Chris@0 94 * @var string Column for session data
Chris@0 95 */
Chris@0 96 private $dataCol = 'sess_data';
Chris@0 97
Chris@0 98 /**
Chris@0 99 * @var string Column for lifetime
Chris@0 100 */
Chris@0 101 private $lifetimeCol = 'sess_lifetime';
Chris@0 102
Chris@0 103 /**
Chris@0 104 * @var string Column for timestamp
Chris@0 105 */
Chris@0 106 private $timeCol = 'sess_time';
Chris@0 107
Chris@0 108 /**
Chris@0 109 * @var string Username when lazy-connect
Chris@0 110 */
Chris@0 111 private $username = '';
Chris@0 112
Chris@0 113 /**
Chris@0 114 * @var string Password when lazy-connect
Chris@0 115 */
Chris@0 116 private $password = '';
Chris@0 117
Chris@0 118 /**
Chris@0 119 * @var array Connection options when lazy-connect
Chris@0 120 */
Chris@17 121 private $connectionOptions = [];
Chris@0 122
Chris@0 123 /**
Chris@0 124 * @var int The strategy for locking, see constants
Chris@0 125 */
Chris@0 126 private $lockMode = self::LOCK_TRANSACTIONAL;
Chris@0 127
Chris@0 128 /**
Chris@0 129 * It's an array to support multiple reads before closing which is manual, non-standard usage.
Chris@0 130 *
Chris@0 131 * @var \PDOStatement[] An array of statements to release advisory locks
Chris@0 132 */
Chris@17 133 private $unlockStatements = [];
Chris@0 134
Chris@0 135 /**
Chris@0 136 * @var bool True when the current session exists but expired according to session.gc_maxlifetime
Chris@0 137 */
Chris@0 138 private $sessionExpired = false;
Chris@0 139
Chris@0 140 /**
Chris@0 141 * @var bool Whether a transaction is active
Chris@0 142 */
Chris@0 143 private $inTransaction = false;
Chris@0 144
Chris@0 145 /**
Chris@0 146 * @var bool Whether gc() has been called
Chris@0 147 */
Chris@0 148 private $gcCalled = false;
Chris@0 149
Chris@0 150 /**
Chris@0 151 * You can either pass an existing database connection as PDO instance or
Chris@0 152 * pass a DSN string that will be used to lazy-connect to the database
Chris@0 153 * when the session is actually used. Furthermore it's possible to pass null
Chris@0 154 * which will then use the session.save_path ini setting as PDO DSN parameter.
Chris@0 155 *
Chris@0 156 * List of available options:
Chris@0 157 * * db_table: The name of the table [default: sessions]
Chris@0 158 * * db_id_col: The column where to store the session id [default: sess_id]
Chris@0 159 * * db_data_col: The column where to store the session data [default: sess_data]
Chris@0 160 * * db_lifetime_col: The column where to store the lifetime [default: sess_lifetime]
Chris@0 161 * * db_time_col: The column where to store the timestamp [default: sess_time]
Chris@0 162 * * db_username: The username when lazy-connect [default: '']
Chris@0 163 * * db_password: The password when lazy-connect [default: '']
Chris@17 164 * * db_connection_options: An array of driver-specific connection options [default: []]
Chris@0 165 * * lock_mode: The strategy for locking, see constants [default: LOCK_TRANSACTIONAL]
Chris@0 166 *
Chris@14 167 * @param \PDO|string|null $pdoOrDsn A \PDO instance or DSN string or URL string or null
Chris@0 168 * @param array $options An associative array of options
Chris@0 169 *
Chris@0 170 * @throws \InvalidArgumentException When PDO error mode is not PDO::ERRMODE_EXCEPTION
Chris@0 171 */
Chris@17 172 public function __construct($pdoOrDsn = null, array $options = [])
Chris@0 173 {
Chris@0 174 if ($pdoOrDsn instanceof \PDO) {
Chris@0 175 if (\PDO::ERRMODE_EXCEPTION !== $pdoOrDsn->getAttribute(\PDO::ATTR_ERRMODE)) {
Chris@0 176 throw new \InvalidArgumentException(sprintf('"%s" requires PDO error mode attribute be set to throw Exceptions (i.e. $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION))', __CLASS__));
Chris@0 177 }
Chris@0 178
Chris@0 179 $this->pdo = $pdoOrDsn;
Chris@0 180 $this->driver = $this->pdo->getAttribute(\PDO::ATTR_DRIVER_NAME);
Chris@17 181 } elseif (\is_string($pdoOrDsn) && false !== strpos($pdoOrDsn, '://')) {
Chris@14 182 $this->dsn = $this->buildDsnFromUrl($pdoOrDsn);
Chris@0 183 } else {
Chris@0 184 $this->dsn = $pdoOrDsn;
Chris@0 185 }
Chris@0 186
Chris@0 187 $this->table = isset($options['db_table']) ? $options['db_table'] : $this->table;
Chris@0 188 $this->idCol = isset($options['db_id_col']) ? $options['db_id_col'] : $this->idCol;
Chris@0 189 $this->dataCol = isset($options['db_data_col']) ? $options['db_data_col'] : $this->dataCol;
Chris@0 190 $this->lifetimeCol = isset($options['db_lifetime_col']) ? $options['db_lifetime_col'] : $this->lifetimeCol;
Chris@0 191 $this->timeCol = isset($options['db_time_col']) ? $options['db_time_col'] : $this->timeCol;
Chris@0 192 $this->username = isset($options['db_username']) ? $options['db_username'] : $this->username;
Chris@0 193 $this->password = isset($options['db_password']) ? $options['db_password'] : $this->password;
Chris@0 194 $this->connectionOptions = isset($options['db_connection_options']) ? $options['db_connection_options'] : $this->connectionOptions;
Chris@0 195 $this->lockMode = isset($options['lock_mode']) ? $options['lock_mode'] : $this->lockMode;
Chris@0 196 }
Chris@0 197
Chris@0 198 /**
Chris@0 199 * Creates the table to store sessions which can be called once for setup.
Chris@0 200 *
Chris@0 201 * Session ID is saved in a column of maximum length 128 because that is enough even
Chris@0 202 * for a 512 bit configured session.hash_function like Whirlpool. Session data is
Chris@0 203 * saved in a BLOB. One could also use a shorter inlined varbinary column
Chris@0 204 * if one was sure the data fits into it.
Chris@0 205 *
Chris@0 206 * @throws \PDOException When the table already exists
Chris@0 207 * @throws \DomainException When an unsupported PDO driver is used
Chris@0 208 */
Chris@0 209 public function createTable()
Chris@0 210 {
Chris@0 211 // connect if we are not yet
Chris@0 212 $this->getConnection();
Chris@0 213
Chris@0 214 switch ($this->driver) {
Chris@0 215 case 'mysql':
Chris@0 216 // We use varbinary for the ID column because it prevents unwanted conversions:
Chris@0 217 // - character set conversions between server and client
Chris@0 218 // - trailing space removal
Chris@0 219 // - case-insensitivity
Chris@0 220 // - language processing like é == e
Chris@0 221 $sql = "CREATE TABLE $this->table ($this->idCol VARBINARY(128) NOT NULL PRIMARY KEY, $this->dataCol BLOB NOT NULL, $this->lifetimeCol MEDIUMINT NOT NULL, $this->timeCol INTEGER UNSIGNED NOT NULL) COLLATE utf8_bin, ENGINE = InnoDB";
Chris@0 222 break;
Chris@0 223 case 'sqlite':
Chris@0 224 $sql = "CREATE TABLE $this->table ($this->idCol TEXT NOT NULL PRIMARY KEY, $this->dataCol BLOB NOT NULL, $this->lifetimeCol INTEGER NOT NULL, $this->timeCol INTEGER NOT NULL)";
Chris@0 225 break;
Chris@0 226 case 'pgsql':
Chris@0 227 $sql = "CREATE TABLE $this->table ($this->idCol VARCHAR(128) NOT NULL PRIMARY KEY, $this->dataCol BYTEA NOT NULL, $this->lifetimeCol INTEGER NOT NULL, $this->timeCol INTEGER NOT NULL)";
Chris@0 228 break;
Chris@0 229 case 'oci':
Chris@0 230 $sql = "CREATE TABLE $this->table ($this->idCol VARCHAR2(128) NOT NULL PRIMARY KEY, $this->dataCol BLOB NOT NULL, $this->lifetimeCol INTEGER NOT NULL, $this->timeCol INTEGER NOT NULL)";
Chris@0 231 break;
Chris@0 232 case 'sqlsrv':
Chris@0 233 $sql = "CREATE TABLE $this->table ($this->idCol VARCHAR(128) NOT NULL PRIMARY KEY, $this->dataCol VARBINARY(MAX) NOT NULL, $this->lifetimeCol INTEGER NOT NULL, $this->timeCol INTEGER NOT NULL)";
Chris@0 234 break;
Chris@0 235 default:
Chris@0 236 throw new \DomainException(sprintf('Creating the session table is currently not implemented for PDO driver "%s".', $this->driver));
Chris@0 237 }
Chris@0 238
Chris@0 239 try {
Chris@0 240 $this->pdo->exec($sql);
Chris@0 241 } catch (\PDOException $e) {
Chris@0 242 $this->rollback();
Chris@0 243
Chris@0 244 throw $e;
Chris@0 245 }
Chris@0 246 }
Chris@0 247
Chris@0 248 /**
Chris@0 249 * Returns true when the current session exists but expired according to session.gc_maxlifetime.
Chris@0 250 *
Chris@0 251 * Can be used to distinguish between a new session and one that expired due to inactivity.
Chris@0 252 *
Chris@0 253 * @return bool Whether current session expired
Chris@0 254 */
Chris@0 255 public function isSessionExpired()
Chris@0 256 {
Chris@0 257 return $this->sessionExpired;
Chris@0 258 }
Chris@0 259
Chris@0 260 /**
Chris@0 261 * {@inheritdoc}
Chris@0 262 */
Chris@0 263 public function open($savePath, $sessionName)
Chris@0 264 {
Chris@14 265 $this->sessionExpired = false;
Chris@14 266
Chris@0 267 if (null === $this->pdo) {
Chris@0 268 $this->connect($this->dsn ?: $savePath);
Chris@0 269 }
Chris@0 270
Chris@14 271 return parent::open($savePath, $sessionName);
Chris@0 272 }
Chris@0 273
Chris@0 274 /**
Chris@0 275 * {@inheritdoc}
Chris@0 276 */
Chris@0 277 public function read($sessionId)
Chris@0 278 {
Chris@0 279 try {
Chris@14 280 return parent::read($sessionId);
Chris@0 281 } catch (\PDOException $e) {
Chris@0 282 $this->rollback();
Chris@0 283
Chris@0 284 throw $e;
Chris@0 285 }
Chris@0 286 }
Chris@0 287
Chris@0 288 /**
Chris@0 289 * {@inheritdoc}
Chris@0 290 */
Chris@0 291 public function gc($maxlifetime)
Chris@0 292 {
Chris@0 293 // We delay gc() to close() so that it is executed outside the transactional and blocking read-write process.
Chris@0 294 // This way, pruning expired sessions does not block them from being started while the current session is used.
Chris@0 295 $this->gcCalled = true;
Chris@0 296
Chris@0 297 return true;
Chris@0 298 }
Chris@0 299
Chris@0 300 /**
Chris@0 301 * {@inheritdoc}
Chris@0 302 */
Chris@14 303 protected function doDestroy($sessionId)
Chris@0 304 {
Chris@0 305 // delete the record associated with this id
Chris@0 306 $sql = "DELETE FROM $this->table WHERE $this->idCol = :id";
Chris@0 307
Chris@0 308 try {
Chris@0 309 $stmt = $this->pdo->prepare($sql);
Chris@0 310 $stmt->bindParam(':id', $sessionId, \PDO::PARAM_STR);
Chris@0 311 $stmt->execute();
Chris@0 312 } catch (\PDOException $e) {
Chris@0 313 $this->rollback();
Chris@0 314
Chris@0 315 throw $e;
Chris@0 316 }
Chris@0 317
Chris@0 318 return true;
Chris@0 319 }
Chris@0 320
Chris@0 321 /**
Chris@0 322 * {@inheritdoc}
Chris@0 323 */
Chris@14 324 protected function doWrite($sessionId, $data)
Chris@0 325 {
Chris@0 326 $maxlifetime = (int) ini_get('session.gc_maxlifetime');
Chris@0 327
Chris@0 328 try {
Chris@0 329 // We use a single MERGE SQL query when supported by the database.
Chris@0 330 $mergeStmt = $this->getMergeStatement($sessionId, $data, $maxlifetime);
Chris@0 331 if (null !== $mergeStmt) {
Chris@0 332 $mergeStmt->execute();
Chris@0 333
Chris@0 334 return true;
Chris@0 335 }
Chris@0 336
Chris@14 337 $updateStmt = $this->getUpdateStatement($sessionId, $data, $maxlifetime);
Chris@0 338 $updateStmt->execute();
Chris@0 339
Chris@0 340 // When MERGE is not supported, like in Postgres < 9.5, we have to use this approach that can result in
Chris@0 341 // duplicate key errors when the same session is written simultaneously (given the LOCK_NONE behavior).
Chris@0 342 // We can just catch such an error and re-execute the update. This is similar to a serializable
Chris@0 343 // transaction with retry logic on serialization failures but without the overhead and without possible
Chris@0 344 // false positives due to longer gap locking.
Chris@0 345 if (!$updateStmt->rowCount()) {
Chris@0 346 try {
Chris@14 347 $insertStmt = $this->getInsertStatement($sessionId, $data, $maxlifetime);
Chris@0 348 $insertStmt->execute();
Chris@0 349 } catch (\PDOException $e) {
Chris@0 350 // Handle integrity violation SQLSTATE 23000 (or a subclass like 23505 in Postgres) for duplicate keys
Chris@0 351 if (0 === strpos($e->getCode(), '23')) {
Chris@0 352 $updateStmt->execute();
Chris@0 353 } else {
Chris@0 354 throw $e;
Chris@0 355 }
Chris@0 356 }
Chris@0 357 }
Chris@0 358 } catch (\PDOException $e) {
Chris@0 359 $this->rollback();
Chris@0 360
Chris@0 361 throw $e;
Chris@0 362 }
Chris@0 363
Chris@0 364 return true;
Chris@0 365 }
Chris@0 366
Chris@0 367 /**
Chris@0 368 * {@inheritdoc}
Chris@0 369 */
Chris@14 370 public function updateTimestamp($sessionId, $data)
Chris@14 371 {
Chris@14 372 $maxlifetime = (int) ini_get('session.gc_maxlifetime');
Chris@14 373
Chris@14 374 try {
Chris@14 375 $updateStmt = $this->pdo->prepare(
Chris@14 376 "UPDATE $this->table SET $this->lifetimeCol = :lifetime, $this->timeCol = :time WHERE $this->idCol = :id"
Chris@14 377 );
Chris@14 378 $updateStmt->bindParam(':id', $sessionId, \PDO::PARAM_STR);
Chris@14 379 $updateStmt->bindParam(':lifetime', $maxlifetime, \PDO::PARAM_INT);
Chris@14 380 $updateStmt->bindValue(':time', time(), \PDO::PARAM_INT);
Chris@14 381 $updateStmt->execute();
Chris@14 382 } catch (\PDOException $e) {
Chris@14 383 $this->rollback();
Chris@14 384
Chris@14 385 throw $e;
Chris@14 386 }
Chris@14 387
Chris@14 388 return true;
Chris@14 389 }
Chris@14 390
Chris@14 391 /**
Chris@14 392 * {@inheritdoc}
Chris@14 393 */
Chris@0 394 public function close()
Chris@0 395 {
Chris@0 396 $this->commit();
Chris@0 397
Chris@0 398 while ($unlockStmt = array_shift($this->unlockStatements)) {
Chris@0 399 $unlockStmt->execute();
Chris@0 400 }
Chris@0 401
Chris@0 402 if ($this->gcCalled) {
Chris@0 403 $this->gcCalled = false;
Chris@0 404
Chris@0 405 // delete the session records that have expired
Chris@14 406 if ('mysql' === $this->driver) {
Chris@14 407 $sql = "DELETE FROM $this->table WHERE $this->lifetimeCol + $this->timeCol < :time";
Chris@14 408 } else {
Chris@14 409 $sql = "DELETE FROM $this->table WHERE $this->lifetimeCol < :time - $this->timeCol";
Chris@14 410 }
Chris@0 411
Chris@0 412 $stmt = $this->pdo->prepare($sql);
Chris@0 413 $stmt->bindValue(':time', time(), \PDO::PARAM_INT);
Chris@0 414 $stmt->execute();
Chris@0 415 }
Chris@0 416
Chris@0 417 if (false !== $this->dsn) {
Chris@0 418 $this->pdo = null; // only close lazy-connection
Chris@0 419 }
Chris@0 420
Chris@0 421 return true;
Chris@0 422 }
Chris@0 423
Chris@0 424 /**
Chris@0 425 * Lazy-connects to the database.
Chris@0 426 *
Chris@0 427 * @param string $dsn DSN string
Chris@0 428 */
Chris@0 429 private function connect($dsn)
Chris@0 430 {
Chris@0 431 $this->pdo = new \PDO($dsn, $this->username, $this->password, $this->connectionOptions);
Chris@0 432 $this->pdo->setAttribute(\PDO::ATTR_ERRMODE, \PDO::ERRMODE_EXCEPTION);
Chris@0 433 $this->driver = $this->pdo->getAttribute(\PDO::ATTR_DRIVER_NAME);
Chris@0 434 }
Chris@0 435
Chris@0 436 /**
Chris@14 437 * Builds a PDO DSN from a URL-like connection string.
Chris@14 438 *
Chris@14 439 * @param string $dsnOrUrl
Chris@14 440 *
Chris@14 441 * @return string
Chris@14 442 *
Chris@14 443 * @todo implement missing support for oci DSN (which look totally different from other PDO ones)
Chris@14 444 */
Chris@14 445 private function buildDsnFromUrl($dsnOrUrl)
Chris@14 446 {
Chris@14 447 // (pdo_)?sqlite3?:///... => (pdo_)?sqlite3?://localhost/... or else the URL will be invalid
Chris@14 448 $url = preg_replace('#^((?:pdo_)?sqlite3?):///#', '$1://localhost/', $dsnOrUrl);
Chris@14 449
Chris@14 450 $params = parse_url($url);
Chris@14 451
Chris@14 452 if (false === $params) {
Chris@14 453 return $dsnOrUrl; // If the URL is not valid, let's assume it might be a DSN already.
Chris@14 454 }
Chris@14 455
Chris@14 456 $params = array_map('rawurldecode', $params);
Chris@14 457
Chris@14 458 // Override the default username and password. Values passed through options will still win over these in the constructor.
Chris@14 459 if (isset($params['user'])) {
Chris@14 460 $this->username = $params['user'];
Chris@14 461 }
Chris@14 462
Chris@14 463 if (isset($params['pass'])) {
Chris@14 464 $this->password = $params['pass'];
Chris@14 465 }
Chris@14 466
Chris@14 467 if (!isset($params['scheme'])) {
Chris@14 468 throw new \InvalidArgumentException('URLs without scheme are not supported to configure the PdoSessionHandler');
Chris@14 469 }
Chris@14 470
Chris@17 471 $driverAliasMap = [
Chris@14 472 'mssql' => 'sqlsrv',
Chris@14 473 'mysql2' => 'mysql', // Amazon RDS, for some weird reason
Chris@14 474 'postgres' => 'pgsql',
Chris@14 475 'postgresql' => 'pgsql',
Chris@14 476 'sqlite3' => 'sqlite',
Chris@17 477 ];
Chris@14 478
Chris@14 479 $driver = isset($driverAliasMap[$params['scheme']]) ? $driverAliasMap[$params['scheme']] : $params['scheme'];
Chris@14 480
Chris@14 481 // Doctrine DBAL supports passing its internal pdo_* driver names directly too (allowing both dashes and underscores). This allows supporting the same here.
Chris@14 482 if (0 === strpos($driver, 'pdo_') || 0 === strpos($driver, 'pdo-')) {
Chris@14 483 $driver = substr($driver, 4);
Chris@14 484 }
Chris@14 485
Chris@14 486 switch ($driver) {
Chris@14 487 case 'mysql':
Chris@14 488 case 'pgsql':
Chris@14 489 $dsn = $driver.':';
Chris@14 490
Chris@14 491 if (isset($params['host']) && '' !== $params['host']) {
Chris@14 492 $dsn .= 'host='.$params['host'].';';
Chris@14 493 }
Chris@14 494
Chris@14 495 if (isset($params['port']) && '' !== $params['port']) {
Chris@14 496 $dsn .= 'port='.$params['port'].';';
Chris@14 497 }
Chris@14 498
Chris@14 499 if (isset($params['path'])) {
Chris@14 500 $dbName = substr($params['path'], 1); // Remove the leading slash
Chris@14 501 $dsn .= 'dbname='.$dbName.';';
Chris@14 502 }
Chris@14 503
Chris@14 504 return $dsn;
Chris@14 505
Chris@14 506 case 'sqlite':
Chris@14 507 return 'sqlite:'.substr($params['path'], 1);
Chris@14 508
Chris@14 509 case 'sqlsrv':
Chris@14 510 $dsn = 'sqlsrv:server=';
Chris@14 511
Chris@14 512 if (isset($params['host'])) {
Chris@14 513 $dsn .= $params['host'];
Chris@14 514 }
Chris@14 515
Chris@14 516 if (isset($params['port']) && '' !== $params['port']) {
Chris@14 517 $dsn .= ','.$params['port'];
Chris@14 518 }
Chris@14 519
Chris@14 520 if (isset($params['path'])) {
Chris@14 521 $dbName = substr($params['path'], 1); // Remove the leading slash
Chris@14 522 $dsn .= ';Database='.$dbName;
Chris@14 523 }
Chris@14 524
Chris@14 525 return $dsn;
Chris@14 526
Chris@14 527 default:
Chris@14 528 throw new \InvalidArgumentException(sprintf('The scheme "%s" is not supported by the PdoSessionHandler URL configuration. Pass a PDO DSN directly.', $params['scheme']));
Chris@14 529 }
Chris@14 530 }
Chris@14 531
Chris@14 532 /**
Chris@0 533 * Helper method to begin a transaction.
Chris@0 534 *
Chris@0 535 * Since SQLite does not support row level locks, we have to acquire a reserved lock
Chris@0 536 * on the database immediately. Because of https://bugs.php.net/42766 we have to create
Chris@0 537 * such a transaction manually which also means we cannot use PDO::commit or
Chris@0 538 * PDO::rollback or PDO::inTransaction for SQLite.
Chris@0 539 *
Chris@0 540 * Also MySQLs default isolation, REPEATABLE READ, causes deadlock for different sessions
Chris@0 541 * due to http://www.mysqlperformanceblog.com/2013/12/12/one-more-innodb-gap-lock-to-avoid/ .
Chris@0 542 * So we change it to READ COMMITTED.
Chris@0 543 */
Chris@0 544 private function beginTransaction()
Chris@0 545 {
Chris@0 546 if (!$this->inTransaction) {
Chris@0 547 if ('sqlite' === $this->driver) {
Chris@0 548 $this->pdo->exec('BEGIN IMMEDIATE TRANSACTION');
Chris@0 549 } else {
Chris@0 550 if ('mysql' === $this->driver) {
Chris@0 551 $this->pdo->exec('SET TRANSACTION ISOLATION LEVEL READ COMMITTED');
Chris@0 552 }
Chris@0 553 $this->pdo->beginTransaction();
Chris@0 554 }
Chris@0 555 $this->inTransaction = true;
Chris@0 556 }
Chris@0 557 }
Chris@0 558
Chris@0 559 /**
Chris@0 560 * Helper method to commit a transaction.
Chris@0 561 */
Chris@0 562 private function commit()
Chris@0 563 {
Chris@0 564 if ($this->inTransaction) {
Chris@0 565 try {
Chris@0 566 // commit read-write transaction which also releases the lock
Chris@0 567 if ('sqlite' === $this->driver) {
Chris@0 568 $this->pdo->exec('COMMIT');
Chris@0 569 } else {
Chris@0 570 $this->pdo->commit();
Chris@0 571 }
Chris@0 572 $this->inTransaction = false;
Chris@0 573 } catch (\PDOException $e) {
Chris@0 574 $this->rollback();
Chris@0 575
Chris@0 576 throw $e;
Chris@0 577 }
Chris@0 578 }
Chris@0 579 }
Chris@0 580
Chris@0 581 /**
Chris@0 582 * Helper method to rollback a transaction.
Chris@0 583 */
Chris@0 584 private function rollback()
Chris@0 585 {
Chris@0 586 // We only need to rollback if we are in a transaction. Otherwise the resulting
Chris@0 587 // error would hide the real problem why rollback was called. We might not be
Chris@0 588 // in a transaction when not using the transactional locking behavior or when
Chris@0 589 // two callbacks (e.g. destroy and write) are invoked that both fail.
Chris@0 590 if ($this->inTransaction) {
Chris@0 591 if ('sqlite' === $this->driver) {
Chris@0 592 $this->pdo->exec('ROLLBACK');
Chris@0 593 } else {
Chris@0 594 $this->pdo->rollBack();
Chris@0 595 }
Chris@0 596 $this->inTransaction = false;
Chris@0 597 }
Chris@0 598 }
Chris@0 599
Chris@0 600 /**
Chris@0 601 * Reads the session data in respect to the different locking strategies.
Chris@0 602 *
Chris@0 603 * We need to make sure we do not return session data that is already considered garbage according
Chris@0 604 * to the session.gc_maxlifetime setting because gc() is called after read() and only sometimes.
Chris@0 605 *
Chris@0 606 * @param string $sessionId Session ID
Chris@0 607 *
Chris@0 608 * @return string The session data
Chris@0 609 */
Chris@14 610 protected function doRead($sessionId)
Chris@0 611 {
Chris@0 612 if (self::LOCK_ADVISORY === $this->lockMode) {
Chris@0 613 $this->unlockStatements[] = $this->doAdvisoryLock($sessionId);
Chris@0 614 }
Chris@0 615
Chris@0 616 $selectSql = $this->getSelectSql();
Chris@0 617 $selectStmt = $this->pdo->prepare($selectSql);
Chris@0 618 $selectStmt->bindParam(':id', $sessionId, \PDO::PARAM_STR);
Chris@16 619 $insertStmt = null;
Chris@0 620
Chris@0 621 do {
Chris@0 622 $selectStmt->execute();
Chris@0 623 $sessionRows = $selectStmt->fetchAll(\PDO::FETCH_NUM);
Chris@0 624
Chris@0 625 if ($sessionRows) {
Chris@0 626 if ($sessionRows[0][1] + $sessionRows[0][2] < time()) {
Chris@0 627 $this->sessionExpired = true;
Chris@0 628
Chris@0 629 return '';
Chris@0 630 }
Chris@0 631
Chris@17 632 return \is_resource($sessionRows[0][0]) ? stream_get_contents($sessionRows[0][0]) : $sessionRows[0][0];
Chris@0 633 }
Chris@0 634
Chris@16 635 if (null !== $insertStmt) {
Chris@16 636 $this->rollback();
Chris@16 637 throw new \RuntimeException('Failed to read session: INSERT reported a duplicate id but next SELECT did not return any data.');
Chris@16 638 }
Chris@16 639
Chris@17 640 if (!filter_var(ini_get('session.use_strict_mode'), FILTER_VALIDATE_BOOLEAN) && self::LOCK_TRANSACTIONAL === $this->lockMode && 'sqlite' !== $this->driver) {
Chris@14 641 // In strict mode, session fixation is not possible: new sessions always start with a unique
Chris@14 642 // random id, so that concurrency is not possible and this code path can be skipped.
Chris@0 643 // Exclusive-reading of non-existent rows does not block, so we need to do an insert to block
Chris@0 644 // until other connections to the session are committed.
Chris@0 645 try {
Chris@14 646 $insertStmt = $this->getInsertStatement($sessionId, '', 0);
Chris@0 647 $insertStmt->execute();
Chris@0 648 } catch (\PDOException $e) {
Chris@0 649 // Catch duplicate key error because other connection created the session already.
Chris@0 650 // It would only not be the case when the other connection destroyed the session.
Chris@0 651 if (0 === strpos($e->getCode(), '23')) {
Chris@0 652 // Retrieve finished session data written by concurrent connection by restarting the loop.
Chris@0 653 // We have to start a new transaction as a failed query will mark the current transaction as
Chris@0 654 // aborted in PostgreSQL and disallow further queries within it.
Chris@0 655 $this->rollback();
Chris@0 656 $this->beginTransaction();
Chris@0 657 continue;
Chris@0 658 }
Chris@0 659
Chris@0 660 throw $e;
Chris@0 661 }
Chris@0 662 }
Chris@0 663
Chris@0 664 return '';
Chris@0 665 } while (true);
Chris@0 666 }
Chris@0 667
Chris@0 668 /**
Chris@0 669 * Executes an application-level lock on the database.
Chris@0 670 *
Chris@0 671 * @param string $sessionId Session ID
Chris@0 672 *
Chris@0 673 * @return \PDOStatement The statement that needs to be executed later to release the lock
Chris@0 674 *
Chris@0 675 * @throws \DomainException When an unsupported PDO driver is used
Chris@0 676 *
Chris@0 677 * @todo implement missing advisory locks
Chris@0 678 * - for oci using DBMS_LOCK.REQUEST
Chris@0 679 * - for sqlsrv using sp_getapplock with LockOwner = Session
Chris@0 680 */
Chris@0 681 private function doAdvisoryLock($sessionId)
Chris@0 682 {
Chris@0 683 switch ($this->driver) {
Chris@0 684 case 'mysql':
Chris@16 685 // MySQL 5.7.5 and later enforces a maximum length on lock names of 64 characters. Previously, no limit was enforced.
Chris@16 686 $lockId = \substr($sessionId, 0, 64);
Chris@0 687 // should we handle the return value? 0 on timeout, null on error
Chris@0 688 // we use a timeout of 50 seconds which is also the default for innodb_lock_wait_timeout
Chris@0 689 $stmt = $this->pdo->prepare('SELECT GET_LOCK(:key, 50)');
Chris@16 690 $stmt->bindValue(':key', $lockId, \PDO::PARAM_STR);
Chris@0 691 $stmt->execute();
Chris@0 692
Chris@0 693 $releaseStmt = $this->pdo->prepare('DO RELEASE_LOCK(:key)');
Chris@16 694 $releaseStmt->bindValue(':key', $lockId, \PDO::PARAM_STR);
Chris@0 695
Chris@0 696 return $releaseStmt;
Chris@0 697 case 'pgsql':
Chris@0 698 // Obtaining an exclusive session level advisory lock requires an integer key.
Chris@14 699 // When session.sid_bits_per_character > 4, the session id can contain non-hex-characters.
Chris@14 700 // So we cannot just use hexdec().
Chris@14 701 if (4 === \PHP_INT_SIZE) {
Chris@14 702 $sessionInt1 = $this->convertStringToInt($sessionId);
Chris@14 703 $sessionInt2 = $this->convertStringToInt(substr($sessionId, 4, 4));
Chris@0 704
Chris@0 705 $stmt = $this->pdo->prepare('SELECT pg_advisory_lock(:key1, :key2)');
Chris@0 706 $stmt->bindValue(':key1', $sessionInt1, \PDO::PARAM_INT);
Chris@0 707 $stmt->bindValue(':key2', $sessionInt2, \PDO::PARAM_INT);
Chris@0 708 $stmt->execute();
Chris@0 709
Chris@0 710 $releaseStmt = $this->pdo->prepare('SELECT pg_advisory_unlock(:key1, :key2)');
Chris@0 711 $releaseStmt->bindValue(':key1', $sessionInt1, \PDO::PARAM_INT);
Chris@0 712 $releaseStmt->bindValue(':key2', $sessionInt2, \PDO::PARAM_INT);
Chris@0 713 } else {
Chris@14 714 $sessionBigInt = $this->convertStringToInt($sessionId);
Chris@0 715
Chris@0 716 $stmt = $this->pdo->prepare('SELECT pg_advisory_lock(:key)');
Chris@0 717 $stmt->bindValue(':key', $sessionBigInt, \PDO::PARAM_INT);
Chris@0 718 $stmt->execute();
Chris@0 719
Chris@0 720 $releaseStmt = $this->pdo->prepare('SELECT pg_advisory_unlock(:key)');
Chris@0 721 $releaseStmt->bindValue(':key', $sessionBigInt, \PDO::PARAM_INT);
Chris@0 722 }
Chris@0 723
Chris@0 724 return $releaseStmt;
Chris@0 725 case 'sqlite':
Chris@0 726 throw new \DomainException('SQLite does not support advisory locks.');
Chris@0 727 default:
Chris@0 728 throw new \DomainException(sprintf('Advisory locks are currently not implemented for PDO driver "%s".', $this->driver));
Chris@0 729 }
Chris@0 730 }
Chris@0 731
Chris@0 732 /**
Chris@14 733 * Encodes the first 4 (when PHP_INT_SIZE == 4) or 8 characters of the string as an integer.
Chris@14 734 *
Chris@14 735 * Keep in mind, PHP integers are signed.
Chris@14 736 *
Chris@14 737 * @param string $string
Chris@14 738 *
Chris@14 739 * @return int
Chris@14 740 */
Chris@14 741 private function convertStringToInt($string)
Chris@14 742 {
Chris@14 743 if (4 === \PHP_INT_SIZE) {
Chris@17 744 return (\ord($string[3]) << 24) + (\ord($string[2]) << 16) + (\ord($string[1]) << 8) + \ord($string[0]);
Chris@14 745 }
Chris@14 746
Chris@17 747 $int1 = (\ord($string[7]) << 24) + (\ord($string[6]) << 16) + (\ord($string[5]) << 8) + \ord($string[4]);
Chris@17 748 $int2 = (\ord($string[3]) << 24) + (\ord($string[2]) << 16) + (\ord($string[1]) << 8) + \ord($string[0]);
Chris@14 749
Chris@14 750 return $int2 + ($int1 << 32);
Chris@14 751 }
Chris@14 752
Chris@14 753 /**
Chris@0 754 * Return a locking or nonlocking SQL query to read session information.
Chris@0 755 *
Chris@0 756 * @return string The SQL string
Chris@0 757 *
Chris@0 758 * @throws \DomainException When an unsupported PDO driver is used
Chris@0 759 */
Chris@0 760 private function getSelectSql()
Chris@0 761 {
Chris@0 762 if (self::LOCK_TRANSACTIONAL === $this->lockMode) {
Chris@0 763 $this->beginTransaction();
Chris@0 764
Chris@0 765 switch ($this->driver) {
Chris@0 766 case 'mysql':
Chris@0 767 case 'oci':
Chris@0 768 case 'pgsql':
Chris@0 769 return "SELECT $this->dataCol, $this->lifetimeCol, $this->timeCol FROM $this->table WHERE $this->idCol = :id FOR UPDATE";
Chris@0 770 case 'sqlsrv':
Chris@0 771 return "SELECT $this->dataCol, $this->lifetimeCol, $this->timeCol FROM $this->table WITH (UPDLOCK, ROWLOCK) WHERE $this->idCol = :id";
Chris@0 772 case 'sqlite':
Chris@0 773 // we already locked when starting transaction
Chris@0 774 break;
Chris@0 775 default:
Chris@0 776 throw new \DomainException(sprintf('Transactional locks are currently not implemented for PDO driver "%s".', $this->driver));
Chris@0 777 }
Chris@0 778 }
Chris@0 779
Chris@0 780 return "SELECT $this->dataCol, $this->lifetimeCol, $this->timeCol FROM $this->table WHERE $this->idCol = :id";
Chris@0 781 }
Chris@0 782
Chris@0 783 /**
Chris@14 784 * Returns an insert statement supported by the database for writing session data.
Chris@14 785 *
Chris@14 786 * @param string $sessionId Session ID
Chris@14 787 * @param string $sessionData Encoded session data
Chris@14 788 * @param int $maxlifetime session.gc_maxlifetime
Chris@14 789 *
Chris@14 790 * @return \PDOStatement The insert statement
Chris@14 791 */
Chris@14 792 private function getInsertStatement($sessionId, $sessionData, $maxlifetime)
Chris@14 793 {
Chris@14 794 switch ($this->driver) {
Chris@14 795 case 'oci':
Chris@14 796 $data = fopen('php://memory', 'r+');
Chris@14 797 fwrite($data, $sessionData);
Chris@14 798 rewind($data);
Chris@14 799 $sql = "INSERT INTO $this->table ($this->idCol, $this->dataCol, $this->lifetimeCol, $this->timeCol) VALUES (:id, EMPTY_BLOB(), :lifetime, :time) RETURNING $this->dataCol into :data";
Chris@14 800 break;
Chris@14 801 default:
Chris@14 802 $data = $sessionData;
Chris@14 803 $sql = "INSERT INTO $this->table ($this->idCol, $this->dataCol, $this->lifetimeCol, $this->timeCol) VALUES (:id, :data, :lifetime, :time)";
Chris@14 804 break;
Chris@14 805 }
Chris@14 806
Chris@14 807 $stmt = $this->pdo->prepare($sql);
Chris@14 808 $stmt->bindParam(':id', $sessionId, \PDO::PARAM_STR);
Chris@14 809 $stmt->bindParam(':data', $data, \PDO::PARAM_LOB);
Chris@14 810 $stmt->bindParam(':lifetime', $maxlifetime, \PDO::PARAM_INT);
Chris@14 811 $stmt->bindValue(':time', time(), \PDO::PARAM_INT);
Chris@14 812
Chris@14 813 return $stmt;
Chris@14 814 }
Chris@14 815
Chris@14 816 /**
Chris@14 817 * Returns an update statement supported by the database for writing session data.
Chris@14 818 *
Chris@14 819 * @param string $sessionId Session ID
Chris@14 820 * @param string $sessionData Encoded session data
Chris@14 821 * @param int $maxlifetime session.gc_maxlifetime
Chris@14 822 *
Chris@14 823 * @return \PDOStatement The update statement
Chris@14 824 */
Chris@14 825 private function getUpdateStatement($sessionId, $sessionData, $maxlifetime)
Chris@14 826 {
Chris@14 827 switch ($this->driver) {
Chris@14 828 case 'oci':
Chris@14 829 $data = fopen('php://memory', 'r+');
Chris@14 830 fwrite($data, $sessionData);
Chris@14 831 rewind($data);
Chris@14 832 $sql = "UPDATE $this->table SET $this->dataCol = EMPTY_BLOB(), $this->lifetimeCol = :lifetime, $this->timeCol = :time WHERE $this->idCol = :id RETURNING $this->dataCol into :data";
Chris@14 833 break;
Chris@14 834 default:
Chris@14 835 $data = $sessionData;
Chris@14 836 $sql = "UPDATE $this->table SET $this->dataCol = :data, $this->lifetimeCol = :lifetime, $this->timeCol = :time WHERE $this->idCol = :id";
Chris@14 837 break;
Chris@14 838 }
Chris@14 839
Chris@14 840 $stmt = $this->pdo->prepare($sql);
Chris@14 841 $stmt->bindParam(':id', $sessionId, \PDO::PARAM_STR);
Chris@14 842 $stmt->bindParam(':data', $data, \PDO::PARAM_LOB);
Chris@14 843 $stmt->bindParam(':lifetime', $maxlifetime, \PDO::PARAM_INT);
Chris@14 844 $stmt->bindValue(':time', time(), \PDO::PARAM_INT);
Chris@14 845
Chris@14 846 return $stmt;
Chris@14 847 }
Chris@14 848
Chris@14 849 /**
Chris@0 850 * Returns a merge/upsert (i.e. insert or update) statement when supported by the database for writing session data.
Chris@0 851 *
Chris@0 852 * @param string $sessionId Session ID
Chris@0 853 * @param string $data Encoded session data
Chris@0 854 * @param int $maxlifetime session.gc_maxlifetime
Chris@0 855 *
Chris@0 856 * @return \PDOStatement|null The merge statement or null when not supported
Chris@0 857 */
Chris@0 858 private function getMergeStatement($sessionId, $data, $maxlifetime)
Chris@0 859 {
Chris@0 860 switch (true) {
Chris@0 861 case 'mysql' === $this->driver:
Chris@0 862 $mergeSql = "INSERT INTO $this->table ($this->idCol, $this->dataCol, $this->lifetimeCol, $this->timeCol) VALUES (:id, :data, :lifetime, :time) ".
Chris@0 863 "ON DUPLICATE KEY UPDATE $this->dataCol = VALUES($this->dataCol), $this->lifetimeCol = VALUES($this->lifetimeCol), $this->timeCol = VALUES($this->timeCol)";
Chris@0 864 break;
Chris@0 865 case 'sqlsrv' === $this->driver && version_compare($this->pdo->getAttribute(\PDO::ATTR_SERVER_VERSION), '10', '>='):
Chris@0 866 // MERGE is only available since SQL Server 2008 and must be terminated by semicolon
Chris@0 867 // It also requires HOLDLOCK according to http://weblogs.sqlteam.com/dang/archive/2009/01/31/UPSERT-Race-Condition-With-MERGE.aspx
Chris@0 868 $mergeSql = "MERGE INTO $this->table WITH (HOLDLOCK) USING (SELECT 1 AS dummy) AS src ON ($this->idCol = ?) ".
Chris@0 869 "WHEN NOT MATCHED THEN INSERT ($this->idCol, $this->dataCol, $this->lifetimeCol, $this->timeCol) VALUES (?, ?, ?, ?) ".
Chris@0 870 "WHEN MATCHED THEN UPDATE SET $this->dataCol = ?, $this->lifetimeCol = ?, $this->timeCol = ?;";
Chris@0 871 break;
Chris@0 872 case 'sqlite' === $this->driver:
Chris@0 873 $mergeSql = "INSERT OR REPLACE INTO $this->table ($this->idCol, $this->dataCol, $this->lifetimeCol, $this->timeCol) VALUES (:id, :data, :lifetime, :time)";
Chris@0 874 break;
Chris@0 875 case 'pgsql' === $this->driver && version_compare($this->pdo->getAttribute(\PDO::ATTR_SERVER_VERSION), '9.5', '>='):
Chris@0 876 $mergeSql = "INSERT INTO $this->table ($this->idCol, $this->dataCol, $this->lifetimeCol, $this->timeCol) VALUES (:id, :data, :lifetime, :time) ".
Chris@0 877 "ON CONFLICT ($this->idCol) DO UPDATE SET ($this->dataCol, $this->lifetimeCol, $this->timeCol) = (EXCLUDED.$this->dataCol, EXCLUDED.$this->lifetimeCol, EXCLUDED.$this->timeCol)";
Chris@0 878 break;
Chris@14 879 default:
Chris@14 880 // MERGE is not supported with LOBs: http://www.oracle.com/technetwork/articles/fuecks-lobs-095315.html
Chris@14 881 return null;
Chris@0 882 }
Chris@0 883
Chris@14 884 $mergeStmt = $this->pdo->prepare($mergeSql);
Chris@0 885
Chris@14 886 if ('sqlsrv' === $this->driver) {
Chris@14 887 $mergeStmt->bindParam(1, $sessionId, \PDO::PARAM_STR);
Chris@14 888 $mergeStmt->bindParam(2, $sessionId, \PDO::PARAM_STR);
Chris@14 889 $mergeStmt->bindParam(3, $data, \PDO::PARAM_LOB);
Chris@14 890 $mergeStmt->bindParam(4, $maxlifetime, \PDO::PARAM_INT);
Chris@14 891 $mergeStmt->bindValue(5, time(), \PDO::PARAM_INT);
Chris@14 892 $mergeStmt->bindParam(6, $data, \PDO::PARAM_LOB);
Chris@14 893 $mergeStmt->bindParam(7, $maxlifetime, \PDO::PARAM_INT);
Chris@14 894 $mergeStmt->bindValue(8, time(), \PDO::PARAM_INT);
Chris@14 895 } else {
Chris@14 896 $mergeStmt->bindParam(':id', $sessionId, \PDO::PARAM_STR);
Chris@14 897 $mergeStmt->bindParam(':data', $data, \PDO::PARAM_LOB);
Chris@14 898 $mergeStmt->bindParam(':lifetime', $maxlifetime, \PDO::PARAM_INT);
Chris@14 899 $mergeStmt->bindValue(':time', time(), \PDO::PARAM_INT);
Chris@14 900 }
Chris@0 901
Chris@14 902 return $mergeStmt;
Chris@0 903 }
Chris@0 904
Chris@0 905 /**
Chris@0 906 * Return a PDO instance.
Chris@0 907 *
Chris@0 908 * @return \PDO
Chris@0 909 */
Chris@0 910 protected function getConnection()
Chris@0 911 {
Chris@0 912 if (null === $this->pdo) {
Chris@0 913 $this->connect($this->dsn ?: ini_get('session.save_path'));
Chris@0 914 }
Chris@0 915
Chris@0 916 return $this->pdo;
Chris@0 917 }
Chris@0 918 }