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943 lines
37 KiB
943 lines
37 KiB
<?php |
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/* |
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* This file is part of the Symfony package. |
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* |
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* (c) Fabien Potencier <fabien@symfony.com> |
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* |
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* For the full copyright and license information, please view the LICENSE |
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* file that was distributed with this source code. |
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*/ |
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namespace Symfony\Component\HttpFoundation\Session\Storage\Handler; |
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/** |
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* Session handler using a PDO connection to read and write data. |
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* |
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* It works with MySQL, PostgreSQL, Oracle, SQL Server and SQLite and implements |
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* different locking strategies to handle concurrent access to the same session. |
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* Locking is necessary to prevent loss of data due to race conditions and to keep |
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* the session data consistent between read() and write(). With locking, requests |
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* for the same session will wait until the other one finished writing. For this |
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* reason it's best practice to close a session as early as possible to improve |
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* concurrency. PHPs internal files session handler also implements locking. |
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* |
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* Attention: Since SQLite does not support row level locks but locks the whole database, |
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* it means only one session can be accessed at a time. Even different sessions would wait |
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* for another to finish. So saving session in SQLite should only be considered for |
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* development or prototypes. |
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* |
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* Session data is a binary string that can contain non-printable characters like the null byte. |
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* For this reason it must be saved in a binary column in the database like BLOB in MySQL. |
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* Saving it in a character column could corrupt the data. You can use createTable() |
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* to initialize a correctly defined table. |
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* |
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* @see https://php.net/sessionhandlerinterface |
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* |
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* @author Fabien Potencier <fabien@symfony.com> |
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* @author Michael Williams <michael.williams@funsational.com> |
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* @author Tobias Schultze <http://tobion.de> |
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*/ |
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class PdoSessionHandler extends AbstractSessionHandler |
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{ |
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/** |
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* No locking is done. This means sessions are prone to loss of data due to |
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* race conditions of concurrent requests to the same session. The last session |
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* write will win in this case. It might be useful when you implement your own |
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* logic to deal with this like an optimistic approach. |
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*/ |
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public const LOCK_NONE = 0; |
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/** |
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* Creates an application-level lock on a session. The disadvantage is that the |
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* lock is not enforced by the database and thus other, unaware parts of the |
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* application could still concurrently modify the session. The advantage is it |
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* does not require a transaction. |
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* This mode is not available for SQLite and not yet implemented for oci and sqlsrv. |
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*/ |
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public const LOCK_ADVISORY = 1; |
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/** |
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* Issues a real row lock. Since it uses a transaction between opening and |
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* closing a session, you have to be careful when you use same database connection |
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* that you also use for your application logic. This mode is the default because |
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* it's the only reliable solution across DBMSs. |
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*/ |
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public const LOCK_TRANSACTIONAL = 2; |
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private const MAX_LIFETIME = 315576000; |
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/** |
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* @var \PDO|null PDO instance or null when not connected yet |
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*/ |
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private $pdo; |
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/** |
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* DSN string or null for session.save_path or false when lazy connection disabled. |
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* |
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* @var string|false|null |
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*/ |
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private $dsn = false; |
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/** |
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* @var string|null |
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*/ |
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private $driver; |
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/** |
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* @var string |
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*/ |
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private $table = 'sessions'; |
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/** |
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* @var string |
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*/ |
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private $idCol = 'sess_id'; |
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/** |
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* @var string |
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*/ |
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private $dataCol = 'sess_data'; |
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/** |
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* @var string |
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*/ |
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private $lifetimeCol = 'sess_lifetime'; |
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/** |
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* @var string |
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*/ |
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private $timeCol = 'sess_time'; |
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/** |
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* Username when lazy-connect. |
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* |
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* @var string |
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*/ |
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private $username = ''; |
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/** |
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* Password when lazy-connect. |
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* |
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* @var string |
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*/ |
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private $password = ''; |
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/** |
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* Connection options when lazy-connect. |
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* |
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* @var array |
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*/ |
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private $connectionOptions = []; |
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/** |
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* The strategy for locking, see constants. |
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* |
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* @var int |
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*/ |
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private $lockMode = self::LOCK_TRANSACTIONAL; |
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|
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/** |
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* It's an array to support multiple reads before closing which is manual, non-standard usage. |
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* |
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* @var \PDOStatement[] An array of statements to release advisory locks |
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*/ |
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private $unlockStatements = []; |
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/** |
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* True when the current session exists but expired according to session.gc_maxlifetime. |
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* |
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* @var bool |
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*/ |
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private $sessionExpired = false; |
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/** |
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* Whether a transaction is active. |
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* |
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* @var bool |
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*/ |
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private $inTransaction = false; |
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/** |
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* Whether gc() has been called. |
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* |
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* @var bool |
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*/ |
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private $gcCalled = false; |
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/** |
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* You can either pass an existing database connection as PDO instance or |
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* pass a DSN string that will be used to lazy-connect to the database |
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* when the session is actually used. Furthermore it's possible to pass null |
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* which will then use the session.save_path ini setting as PDO DSN parameter. |
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* |
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* List of available options: |
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* * db_table: The name of the table [default: sessions] |
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* * db_id_col: The column where to store the session id [default: sess_id] |
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* * db_data_col: The column where to store the session data [default: sess_data] |
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* * db_lifetime_col: The column where to store the lifetime [default: sess_lifetime] |
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* * db_time_col: The column where to store the timestamp [default: sess_time] |
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* * db_username: The username when lazy-connect [default: ''] |
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* * db_password: The password when lazy-connect [default: ''] |
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* * db_connection_options: An array of driver-specific connection options [default: []] |
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* * lock_mode: The strategy for locking, see constants [default: LOCK_TRANSACTIONAL] |
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* |
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* @param \PDO|string|null $pdoOrDsn A \PDO instance or DSN string or URL string or null |
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* |
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* @throws \InvalidArgumentException When PDO error mode is not PDO::ERRMODE_EXCEPTION |
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*/ |
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public function __construct($pdoOrDsn = null, array $options = []) |
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{ |
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if ($pdoOrDsn instanceof \PDO) { |
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if (\PDO::ERRMODE_EXCEPTION !== $pdoOrDsn->getAttribute(\PDO::ATTR_ERRMODE)) { |
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throw new \InvalidArgumentException(sprintf('"%s" requires PDO error mode attribute be set to throw Exceptions (i.e. $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION)).', __CLASS__)); |
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} |
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$this->pdo = $pdoOrDsn; |
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$this->driver = $this->pdo->getAttribute(\PDO::ATTR_DRIVER_NAME); |
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} elseif (\is_string($pdoOrDsn) && str_contains($pdoOrDsn, '://')) { |
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$this->dsn = $this->buildDsnFromUrl($pdoOrDsn); |
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} else { |
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$this->dsn = $pdoOrDsn; |
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} |
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$this->table = $options['db_table'] ?? $this->table; |
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$this->idCol = $options['db_id_col'] ?? $this->idCol; |
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$this->dataCol = $options['db_data_col'] ?? $this->dataCol; |
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$this->lifetimeCol = $options['db_lifetime_col'] ?? $this->lifetimeCol; |
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$this->timeCol = $options['db_time_col'] ?? $this->timeCol; |
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$this->username = $options['db_username'] ?? $this->username; |
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$this->password = $options['db_password'] ?? $this->password; |
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$this->connectionOptions = $options['db_connection_options'] ?? $this->connectionOptions; |
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$this->lockMode = $options['lock_mode'] ?? $this->lockMode; |
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} |
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/** |
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* Creates the table to store sessions which can be called once for setup. |
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* |
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* Session ID is saved in a column of maximum length 128 because that is enough even |
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* for a 512 bit configured session.hash_function like Whirlpool. Session data is |
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* saved in a BLOB. One could also use a shorter inlined varbinary column |
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* if one was sure the data fits into it. |
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* |
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* @throws \PDOException When the table already exists |
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* @throws \DomainException When an unsupported PDO driver is used |
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*/ |
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public function createTable() |
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{ |
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// connect if we are not yet |
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$this->getConnection(); |
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switch ($this->driver) { |
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case 'mysql': |
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// We use varbinary for the ID column because it prevents unwanted conversions: |
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// - character set conversions between server and client |
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// - trailing space removal |
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// - case-insensitivity |
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// - language processing like é == e |
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$sql = "CREATE TABLE $this->table ($this->idCol VARBINARY(128) NOT NULL PRIMARY KEY, $this->dataCol BLOB NOT NULL, $this->lifetimeCol INTEGER UNSIGNED NOT NULL, $this->timeCol INTEGER UNSIGNED NOT NULL) COLLATE utf8mb4_bin, ENGINE = InnoDB"; |
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break; |
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case 'sqlite': |
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$sql = "CREATE TABLE $this->table ($this->idCol TEXT NOT NULL PRIMARY KEY, $this->dataCol BLOB NOT NULL, $this->lifetimeCol INTEGER NOT NULL, $this->timeCol INTEGER NOT NULL)"; |
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break; |
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case 'pgsql': |
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$sql = "CREATE TABLE $this->table ($this->idCol VARCHAR(128) NOT NULL PRIMARY KEY, $this->dataCol BYTEA NOT NULL, $this->lifetimeCol INTEGER NOT NULL, $this->timeCol INTEGER NOT NULL)"; |
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break; |
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case 'oci': |
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$sql = "CREATE TABLE $this->table ($this->idCol VARCHAR2(128) NOT NULL PRIMARY KEY, $this->dataCol BLOB NOT NULL, $this->lifetimeCol INTEGER NOT NULL, $this->timeCol INTEGER NOT NULL)"; |
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break; |
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case 'sqlsrv': |
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$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)"; |
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break; |
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default: |
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throw new \DomainException(sprintf('Creating the session table is currently not implemented for PDO driver "%s".', $this->driver)); |
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} |
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try { |
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$this->pdo->exec($sql); |
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$this->pdo->exec("CREATE INDEX EXPIRY ON $this->table ($this->lifetimeCol)"); |
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} catch (\PDOException $e) { |
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$this->rollback(); |
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throw $e; |
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} |
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} |
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/** |
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* Returns true when the current session exists but expired according to session.gc_maxlifetime. |
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* |
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* Can be used to distinguish between a new session and one that expired due to inactivity. |
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* |
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* @return bool |
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*/ |
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public function isSessionExpired() |
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{ |
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return $this->sessionExpired; |
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} |
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/** |
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* @return bool |
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*/ |
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#[\ReturnTypeWillChange] |
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public function open($savePath, $sessionName) |
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{ |
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$this->sessionExpired = false; |
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if (null === $this->pdo) { |
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$this->connect($this->dsn ?: $savePath); |
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} |
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return parent::open($savePath, $sessionName); |
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} |
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/** |
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* @return string |
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*/ |
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#[\ReturnTypeWillChange] |
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public function read($sessionId) |
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{ |
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try { |
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return parent::read($sessionId); |
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} catch (\PDOException $e) { |
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$this->rollback(); |
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throw $e; |
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} |
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} |
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/** |
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* @return int|false |
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*/ |
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#[\ReturnTypeWillChange] |
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public function gc($maxlifetime) |
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{ |
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// We delay gc() to close() so that it is executed outside the transactional and blocking read-write process. |
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// This way, pruning expired sessions does not block them from being started while the current session is used. |
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$this->gcCalled = true; |
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return 0; |
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} |
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/** |
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* {@inheritdoc} |
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*/ |
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protected function doDestroy(string $sessionId) |
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{ |
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// delete the record associated with this id |
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$sql = "DELETE FROM $this->table WHERE $this->idCol = :id"; |
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try { |
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$stmt = $this->pdo->prepare($sql); |
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$stmt->bindParam(':id', $sessionId, \PDO::PARAM_STR); |
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$stmt->execute(); |
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} catch (\PDOException $e) { |
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$this->rollback(); |
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throw $e; |
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} |
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return true; |
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} |
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/** |
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* {@inheritdoc} |
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*/ |
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protected function doWrite(string $sessionId, string $data) |
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{ |
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$maxlifetime = (int) \ini_get('session.gc_maxlifetime'); |
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try { |
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// We use a single MERGE SQL query when supported by the database. |
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$mergeStmt = $this->getMergeStatement($sessionId, $data, $maxlifetime); |
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if (null !== $mergeStmt) { |
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$mergeStmt->execute(); |
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return true; |
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} |
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$updateStmt = $this->getUpdateStatement($sessionId, $data, $maxlifetime); |
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$updateStmt->execute(); |
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// When MERGE is not supported, like in Postgres < 9.5, we have to use this approach that can result in |
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// duplicate key errors when the same session is written simultaneously (given the LOCK_NONE behavior). |
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// We can just catch such an error and re-execute the update. This is similar to a serializable |
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// transaction with retry logic on serialization failures but without the overhead and without possible |
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// false positives due to longer gap locking. |
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if (!$updateStmt->rowCount()) { |
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try { |
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$insertStmt = $this->getInsertStatement($sessionId, $data, $maxlifetime); |
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$insertStmt->execute(); |
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} catch (\PDOException $e) { |
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// Handle integrity violation SQLSTATE 23000 (or a subclass like 23505 in Postgres) for duplicate keys |
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if (str_starts_with($e->getCode(), '23')) { |
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$updateStmt->execute(); |
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} else { |
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throw $e; |
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} |
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} |
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} |
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} catch (\PDOException $e) { |
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$this->rollback(); |
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throw $e; |
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} |
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return true; |
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} |
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/** |
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* @return bool |
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*/ |
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#[\ReturnTypeWillChange] |
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public function updateTimestamp($sessionId, $data) |
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{ |
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$expiry = time() + (int) \ini_get('session.gc_maxlifetime'); |
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try { |
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$updateStmt = $this->pdo->prepare( |
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"UPDATE $this->table SET $this->lifetimeCol = :expiry, $this->timeCol = :time WHERE $this->idCol = :id" |
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); |
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$updateStmt->bindValue(':id', $sessionId, \PDO::PARAM_STR); |
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$updateStmt->bindValue(':expiry', $expiry, \PDO::PARAM_INT); |
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$updateStmt->bindValue(':time', time(), \PDO::PARAM_INT); |
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$updateStmt->execute(); |
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} catch (\PDOException $e) { |
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$this->rollback(); |
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throw $e; |
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} |
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return true; |
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} |
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/** |
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* @return bool |
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*/ |
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#[\ReturnTypeWillChange] |
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public function close() |
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{ |
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$this->commit(); |
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while ($unlockStmt = array_shift($this->unlockStatements)) { |
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$unlockStmt->execute(); |
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} |
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if ($this->gcCalled) { |
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$this->gcCalled = false; |
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// delete the session records that have expired |
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$sql = "DELETE FROM $this->table WHERE $this->lifetimeCol < :time AND $this->lifetimeCol > :min"; |
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$stmt = $this->pdo->prepare($sql); |
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$stmt->bindValue(':time', time(), \PDO::PARAM_INT); |
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$stmt->bindValue(':min', self::MAX_LIFETIME, \PDO::PARAM_INT); |
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$stmt->execute(); |
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// to be removed in 6.0 |
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if ('mysql' === $this->driver) { |
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$legacySql = "DELETE FROM $this->table WHERE $this->lifetimeCol <= :min AND $this->lifetimeCol + $this->timeCol < :time"; |
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} else { |
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$legacySql = "DELETE FROM $this->table WHERE $this->lifetimeCol <= :min AND $this->lifetimeCol < :time - $this->timeCol"; |
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} |
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$stmt = $this->pdo->prepare($legacySql); |
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$stmt->bindValue(':time', time(), \PDO::PARAM_INT); |
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$stmt->bindValue(':min', self::MAX_LIFETIME, \PDO::PARAM_INT); |
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$stmt->execute(); |
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} |
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|
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if (false !== $this->dsn) { |
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$this->pdo = null; // only close lazy-connection |
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$this->driver = null; |
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} |
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return true; |
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} |
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|
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/** |
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* Lazy-connects to the database. |
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*/ |
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private function connect(string $dsn): void |
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{ |
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$this->pdo = new \PDO($dsn, $this->username, $this->password, $this->connectionOptions); |
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$this->pdo->setAttribute(\PDO::ATTR_ERRMODE, \PDO::ERRMODE_EXCEPTION); |
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$this->driver = $this->pdo->getAttribute(\PDO::ATTR_DRIVER_NAME); |
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} |
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|
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/** |
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* Builds a PDO DSN from a URL-like connection string. |
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* |
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* @todo implement missing support for oci DSN (which look totally different from other PDO ones) |
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*/ |
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private function buildDsnFromUrl(string $dsnOrUrl): string |
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{ |
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// (pdo_)?sqlite3?:///... => (pdo_)?sqlite3?://localhost/... or else the URL will be invalid |
|
$url = preg_replace('#^((?:pdo_)?sqlite3?):///#', '$1://localhost/', $dsnOrUrl); |
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|
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$params = parse_url($url); |
|
|
|
if (false === $params) { |
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return $dsnOrUrl; // If the URL is not valid, let's assume it might be a DSN already. |
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} |
|
|
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$params = array_map('rawurldecode', $params); |
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|
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// Override the default username and password. Values passed through options will still win over these in the constructor. |
|
if (isset($params['user'])) { |
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$this->username = $params['user']; |
|
} |
|
|
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if (isset($params['pass'])) { |
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$this->password = $params['pass']; |
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} |
|
|
|
if (!isset($params['scheme'])) { |
|
throw new \InvalidArgumentException('URLs without scheme are not supported to configure the PdoSessionHandler.'); |
|
} |
|
|
|
$driverAliasMap = [ |
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'mssql' => 'sqlsrv', |
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'mysql2' => 'mysql', // Amazon RDS, for some weird reason |
|
'postgres' => 'pgsql', |
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'postgresql' => 'pgsql', |
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'sqlite3' => 'sqlite', |
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]; |
|
|
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$driver = $driverAliasMap[$params['scheme']] ?? $params['scheme']; |
|
|
|
// Doctrine DBAL supports passing its internal pdo_* driver names directly too (allowing both dashes and underscores). This allows supporting the same here. |
|
if (str_starts_with($driver, 'pdo_') || str_starts_with($driver, 'pdo-')) { |
|
$driver = substr($driver, 4); |
|
} |
|
|
|
$dsn = null; |
|
switch ($driver) { |
|
case 'mysql': |
|
$dsn = 'mysql:'; |
|
if ('' !== ($params['query'] ?? '')) { |
|
$queryParams = []; |
|
parse_str($params['query'], $queryParams); |
|
if ('' !== ($queryParams['charset'] ?? '')) { |
|
$dsn .= 'charset='.$queryParams['charset'].';'; |
|
} |
|
|
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if ('' !== ($queryParams['unix_socket'] ?? '')) { |
|
$dsn .= 'unix_socket='.$queryParams['unix_socket'].';'; |
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|
|
if (isset($params['path'])) { |
|
$dbName = substr($params['path'], 1); // Remove the leading slash |
|
$dsn .= 'dbname='.$dbName.';'; |
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} |
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|
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return $dsn; |
|
} |
|
} |
|
// If "unix_socket" is not in the query, we continue with the same process as pgsql |
|
// no break |
|
case 'pgsql': |
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$dsn ?? $dsn = 'pgsql:'; |
|
|
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if (isset($params['host']) && '' !== $params['host']) { |
|
$dsn .= 'host='.$params['host'].';'; |
|
} |
|
|
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if (isset($params['port']) && '' !== $params['port']) { |
|
$dsn .= 'port='.$params['port'].';'; |
|
} |
|
|
|
if (isset($params['path'])) { |
|
$dbName = substr($params['path'], 1); // Remove the leading slash |
|
$dsn .= 'dbname='.$dbName.';'; |
|
} |
|
|
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return $dsn; |
|
|
|
case 'sqlite': |
|
return 'sqlite:'.substr($params['path'], 1); |
|
|
|
case 'sqlsrv': |
|
$dsn = 'sqlsrv:server='; |
|
|
|
if (isset($params['host'])) { |
|
$dsn .= $params['host']; |
|
} |
|
|
|
if (isset($params['port']) && '' !== $params['port']) { |
|
$dsn .= ','.$params['port']; |
|
} |
|
|
|
if (isset($params['path'])) { |
|
$dbName = substr($params['path'], 1); // Remove the leading slash |
|
$dsn .= ';Database='.$dbName; |
|
} |
|
|
|
return $dsn; |
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|
|
default: |
|
throw new \InvalidArgumentException(sprintf('The scheme "%s" is not supported by the PdoSessionHandler URL configuration. Pass a PDO DSN directly.', $params['scheme'])); |
|
} |
|
} |
|
|
|
/** |
|
* Helper method to begin a transaction. |
|
* |
|
* Since SQLite does not support row level locks, we have to acquire a reserved lock |
|
* on the database immediately. Because of https://bugs.php.net/42766 we have to create |
|
* such a transaction manually which also means we cannot use PDO::commit or |
|
* PDO::rollback or PDO::inTransaction for SQLite. |
|
* |
|
* Also MySQLs default isolation, REPEATABLE READ, causes deadlock for different sessions |
|
* due to https://percona.com/blog/2013/12/12/one-more-innodb-gap-lock-to-avoid/ . |
|
* So we change it to READ COMMITTED. |
|
*/ |
|
private function beginTransaction(): void |
|
{ |
|
if (!$this->inTransaction) { |
|
if ('sqlite' === $this->driver) { |
|
$this->pdo->exec('BEGIN IMMEDIATE TRANSACTION'); |
|
} else { |
|
if ('mysql' === $this->driver) { |
|
$this->pdo->exec('SET TRANSACTION ISOLATION LEVEL READ COMMITTED'); |
|
} |
|
$this->pdo->beginTransaction(); |
|
} |
|
$this->inTransaction = true; |
|
} |
|
} |
|
|
|
/** |
|
* Helper method to commit a transaction. |
|
*/ |
|
private function commit(): void |
|
{ |
|
if ($this->inTransaction) { |
|
try { |
|
// commit read-write transaction which also releases the lock |
|
if ('sqlite' === $this->driver) { |
|
$this->pdo->exec('COMMIT'); |
|
} else { |
|
$this->pdo->commit(); |
|
} |
|
$this->inTransaction = false; |
|
} catch (\PDOException $e) { |
|
$this->rollback(); |
|
|
|
throw $e; |
|
} |
|
} |
|
} |
|
|
|
/** |
|
* Helper method to rollback a transaction. |
|
*/ |
|
private function rollback(): void |
|
{ |
|
// We only need to rollback if we are in a transaction. Otherwise the resulting |
|
// error would hide the real problem why rollback was called. We might not be |
|
// in a transaction when not using the transactional locking behavior or when |
|
// two callbacks (e.g. destroy and write) are invoked that both fail. |
|
if ($this->inTransaction) { |
|
if ('sqlite' === $this->driver) { |
|
$this->pdo->exec('ROLLBACK'); |
|
} else { |
|
$this->pdo->rollBack(); |
|
} |
|
$this->inTransaction = false; |
|
} |
|
} |
|
|
|
/** |
|
* Reads the session data in respect to the different locking strategies. |
|
* |
|
* We need to make sure we do not return session data that is already considered garbage according |
|
* to the session.gc_maxlifetime setting because gc() is called after read() and only sometimes. |
|
* |
|
* @return string |
|
*/ |
|
protected function doRead(string $sessionId) |
|
{ |
|
if (self::LOCK_ADVISORY === $this->lockMode) { |
|
$this->unlockStatements[] = $this->doAdvisoryLock($sessionId); |
|
} |
|
|
|
$selectSql = $this->getSelectSql(); |
|
$selectStmt = $this->pdo->prepare($selectSql); |
|
$selectStmt->bindParam(':id', $sessionId, \PDO::PARAM_STR); |
|
$insertStmt = null; |
|
|
|
while (true) { |
|
$selectStmt->execute(); |
|
$sessionRows = $selectStmt->fetchAll(\PDO::FETCH_NUM); |
|
|
|
if ($sessionRows) { |
|
$expiry = (int) $sessionRows[0][1]; |
|
if ($expiry <= self::MAX_LIFETIME) { |
|
$expiry += $sessionRows[0][2]; |
|
} |
|
|
|
if ($expiry < time()) { |
|
$this->sessionExpired = true; |
|
|
|
return ''; |
|
} |
|
|
|
return \is_resource($sessionRows[0][0]) ? stream_get_contents($sessionRows[0][0]) : $sessionRows[0][0]; |
|
} |
|
|
|
if (null !== $insertStmt) { |
|
$this->rollback(); |
|
throw new \RuntimeException('Failed to read session: INSERT reported a duplicate id but next SELECT did not return any data.'); |
|
} |
|
|
|
if (!filter_var(\ini_get('session.use_strict_mode'), \FILTER_VALIDATE_BOOLEAN) && self::LOCK_TRANSACTIONAL === $this->lockMode && 'sqlite' !== $this->driver) { |
|
// In strict mode, session fixation is not possible: new sessions always start with a unique |
|
// random id, so that concurrency is not possible and this code path can be skipped. |
|
// Exclusive-reading of non-existent rows does not block, so we need to do an insert to block |
|
// until other connections to the session are committed. |
|
try { |
|
$insertStmt = $this->getInsertStatement($sessionId, '', 0); |
|
$insertStmt->execute(); |
|
} catch (\PDOException $e) { |
|
// Catch duplicate key error because other connection created the session already. |
|
// It would only not be the case when the other connection destroyed the session. |
|
if (str_starts_with($e->getCode(), '23')) { |
|
// Retrieve finished session data written by concurrent connection by restarting the loop. |
|
// We have to start a new transaction as a failed query will mark the current transaction as |
|
// aborted in PostgreSQL and disallow further queries within it. |
|
$this->rollback(); |
|
$this->beginTransaction(); |
|
continue; |
|
} |
|
|
|
throw $e; |
|
} |
|
} |
|
|
|
return ''; |
|
} |
|
} |
|
|
|
/** |
|
* Executes an application-level lock on the database. |
|
* |
|
* @return \PDOStatement The statement that needs to be executed later to release the lock |
|
* |
|
* @throws \DomainException When an unsupported PDO driver is used |
|
* |
|
* @todo implement missing advisory locks |
|
* - for oci using DBMS_LOCK.REQUEST |
|
* - for sqlsrv using sp_getapplock with LockOwner = Session |
|
*/ |
|
private function doAdvisoryLock(string $sessionId): \PDOStatement |
|
{ |
|
switch ($this->driver) { |
|
case 'mysql': |
|
// MySQL 5.7.5 and later enforces a maximum length on lock names of 64 characters. Previously, no limit was enforced. |
|
$lockId = substr($sessionId, 0, 64); |
|
// should we handle the return value? 0 on timeout, null on error |
|
// we use a timeout of 50 seconds which is also the default for innodb_lock_wait_timeout |
|
$stmt = $this->pdo->prepare('SELECT GET_LOCK(:key, 50)'); |
|
$stmt->bindValue(':key', $lockId, \PDO::PARAM_STR); |
|
$stmt->execute(); |
|
|
|
$releaseStmt = $this->pdo->prepare('DO RELEASE_LOCK(:key)'); |
|
$releaseStmt->bindValue(':key', $lockId, \PDO::PARAM_STR); |
|
|
|
return $releaseStmt; |
|
case 'pgsql': |
|
// Obtaining an exclusive session level advisory lock requires an integer key. |
|
// When session.sid_bits_per_character > 4, the session id can contain non-hex-characters. |
|
// So we cannot just use hexdec(). |
|
if (4 === \PHP_INT_SIZE) { |
|
$sessionInt1 = $this->convertStringToInt($sessionId); |
|
$sessionInt2 = $this->convertStringToInt(substr($sessionId, 4, 4)); |
|
|
|
$stmt = $this->pdo->prepare('SELECT pg_advisory_lock(:key1, :key2)'); |
|
$stmt->bindValue(':key1', $sessionInt1, \PDO::PARAM_INT); |
|
$stmt->bindValue(':key2', $sessionInt2, \PDO::PARAM_INT); |
|
$stmt->execute(); |
|
|
|
$releaseStmt = $this->pdo->prepare('SELECT pg_advisory_unlock(:key1, :key2)'); |
|
$releaseStmt->bindValue(':key1', $sessionInt1, \PDO::PARAM_INT); |
|
$releaseStmt->bindValue(':key2', $sessionInt2, \PDO::PARAM_INT); |
|
} else { |
|
$sessionBigInt = $this->convertStringToInt($sessionId); |
|
|
|
$stmt = $this->pdo->prepare('SELECT pg_advisory_lock(:key)'); |
|
$stmt->bindValue(':key', $sessionBigInt, \PDO::PARAM_INT); |
|
$stmt->execute(); |
|
|
|
$releaseStmt = $this->pdo->prepare('SELECT pg_advisory_unlock(:key)'); |
|
$releaseStmt->bindValue(':key', $sessionBigInt, \PDO::PARAM_INT); |
|
} |
|
|
|
return $releaseStmt; |
|
case 'sqlite': |
|
throw new \DomainException('SQLite does not support advisory locks.'); |
|
default: |
|
throw new \DomainException(sprintf('Advisory locks are currently not implemented for PDO driver "%s".', $this->driver)); |
|
} |
|
} |
|
|
|
/** |
|
* Encodes the first 4 (when PHP_INT_SIZE == 4) or 8 characters of the string as an integer. |
|
* |
|
* Keep in mind, PHP integers are signed. |
|
*/ |
|
private function convertStringToInt(string $string): int |
|
{ |
|
if (4 === \PHP_INT_SIZE) { |
|
return (\ord($string[3]) << 24) + (\ord($string[2]) << 16) + (\ord($string[1]) << 8) + \ord($string[0]); |
|
} |
|
|
|
$int1 = (\ord($string[7]) << 24) + (\ord($string[6]) << 16) + (\ord($string[5]) << 8) + \ord($string[4]); |
|
$int2 = (\ord($string[3]) << 24) + (\ord($string[2]) << 16) + (\ord($string[1]) << 8) + \ord($string[0]); |
|
|
|
return $int2 + ($int1 << 32); |
|
} |
|
|
|
/** |
|
* Return a locking or nonlocking SQL query to read session information. |
|
* |
|
* @throws \DomainException When an unsupported PDO driver is used |
|
*/ |
|
private function getSelectSql(): string |
|
{ |
|
if (self::LOCK_TRANSACTIONAL === $this->lockMode) { |
|
$this->beginTransaction(); |
|
|
|
// selecting the time column should be removed in 6.0 |
|
switch ($this->driver) { |
|
case 'mysql': |
|
case 'oci': |
|
case 'pgsql': |
|
return "SELECT $this->dataCol, $this->lifetimeCol, $this->timeCol FROM $this->table WHERE $this->idCol = :id FOR UPDATE"; |
|
case 'sqlsrv': |
|
return "SELECT $this->dataCol, $this->lifetimeCol, $this->timeCol FROM $this->table WITH (UPDLOCK, ROWLOCK) WHERE $this->idCol = :id"; |
|
case 'sqlite': |
|
// we already locked when starting transaction |
|
break; |
|
default: |
|
throw new \DomainException(sprintf('Transactional locks are currently not implemented for PDO driver "%s".', $this->driver)); |
|
} |
|
} |
|
|
|
return "SELECT $this->dataCol, $this->lifetimeCol, $this->timeCol FROM $this->table WHERE $this->idCol = :id"; |
|
} |
|
|
|
/** |
|
* Returns an insert statement supported by the database for writing session data. |
|
*/ |
|
private function getInsertStatement(string $sessionId, string $sessionData, int $maxlifetime): \PDOStatement |
|
{ |
|
switch ($this->driver) { |
|
case 'oci': |
|
$data = fopen('php://memory', 'r+'); |
|
fwrite($data, $sessionData); |
|
rewind($data); |
|
$sql = "INSERT INTO $this->table ($this->idCol, $this->dataCol, $this->lifetimeCol, $this->timeCol) VALUES (:id, EMPTY_BLOB(), :expiry, :time) RETURNING $this->dataCol into :data"; |
|
break; |
|
default: |
|
$data = $sessionData; |
|
$sql = "INSERT INTO $this->table ($this->idCol, $this->dataCol, $this->lifetimeCol, $this->timeCol) VALUES (:id, :data, :expiry, :time)"; |
|
break; |
|
} |
|
|
|
$stmt = $this->pdo->prepare($sql); |
|
$stmt->bindParam(':id', $sessionId, \PDO::PARAM_STR); |
|
$stmt->bindParam(':data', $data, \PDO::PARAM_LOB); |
|
$stmt->bindValue(':expiry', time() + $maxlifetime, \PDO::PARAM_INT); |
|
$stmt->bindValue(':time', time(), \PDO::PARAM_INT); |
|
|
|
return $stmt; |
|
} |
|
|
|
/** |
|
* Returns an update statement supported by the database for writing session data. |
|
*/ |
|
private function getUpdateStatement(string $sessionId, string $sessionData, int $maxlifetime): \PDOStatement |
|
{ |
|
switch ($this->driver) { |
|
case 'oci': |
|
$data = fopen('php://memory', 'r+'); |
|
fwrite($data, $sessionData); |
|
rewind($data); |
|
$sql = "UPDATE $this->table SET $this->dataCol = EMPTY_BLOB(), $this->lifetimeCol = :expiry, $this->timeCol = :time WHERE $this->idCol = :id RETURNING $this->dataCol into :data"; |
|
break; |
|
default: |
|
$data = $sessionData; |
|
$sql = "UPDATE $this->table SET $this->dataCol = :data, $this->lifetimeCol = :expiry, $this->timeCol = :time WHERE $this->idCol = :id"; |
|
break; |
|
} |
|
|
|
$stmt = $this->pdo->prepare($sql); |
|
$stmt->bindParam(':id', $sessionId, \PDO::PARAM_STR); |
|
$stmt->bindParam(':data', $data, \PDO::PARAM_LOB); |
|
$stmt->bindValue(':expiry', time() + $maxlifetime, \PDO::PARAM_INT); |
|
$stmt->bindValue(':time', time(), \PDO::PARAM_INT); |
|
|
|
return $stmt; |
|
} |
|
|
|
/** |
|
* Returns a merge/upsert (i.e. insert or update) statement when supported by the database for writing session data. |
|
*/ |
|
private function getMergeStatement(string $sessionId, string $data, int $maxlifetime): ?\PDOStatement |
|
{ |
|
switch (true) { |
|
case 'mysql' === $this->driver: |
|
$mergeSql = "INSERT INTO $this->table ($this->idCol, $this->dataCol, $this->lifetimeCol, $this->timeCol) VALUES (:id, :data, :expiry, :time) ". |
|
"ON DUPLICATE KEY UPDATE $this->dataCol = VALUES($this->dataCol), $this->lifetimeCol = VALUES($this->lifetimeCol), $this->timeCol = VALUES($this->timeCol)"; |
|
break; |
|
case 'sqlsrv' === $this->driver && version_compare($this->pdo->getAttribute(\PDO::ATTR_SERVER_VERSION), '10', '>='): |
|
// MERGE is only available since SQL Server 2008 and must be terminated by semicolon |
|
// It also requires HOLDLOCK according to https://weblogs.sqlteam.com/dang/2009/01/31/upsert-race-condition-with-merge/ |
|
$mergeSql = "MERGE INTO $this->table WITH (HOLDLOCK) USING (SELECT 1 AS dummy) AS src ON ($this->idCol = ?) ". |
|
"WHEN NOT MATCHED THEN INSERT ($this->idCol, $this->dataCol, $this->lifetimeCol, $this->timeCol) VALUES (?, ?, ?, ?) ". |
|
"WHEN MATCHED THEN UPDATE SET $this->dataCol = ?, $this->lifetimeCol = ?, $this->timeCol = ?;"; |
|
break; |
|
case 'sqlite' === $this->driver: |
|
$mergeSql = "INSERT OR REPLACE INTO $this->table ($this->idCol, $this->dataCol, $this->lifetimeCol, $this->timeCol) VALUES (:id, :data, :expiry, :time)"; |
|
break; |
|
case 'pgsql' === $this->driver && version_compare($this->pdo->getAttribute(\PDO::ATTR_SERVER_VERSION), '9.5', '>='): |
|
$mergeSql = "INSERT INTO $this->table ($this->idCol, $this->dataCol, $this->lifetimeCol, $this->timeCol) VALUES (:id, :data, :expiry, :time) ". |
|
"ON CONFLICT ($this->idCol) DO UPDATE SET ($this->dataCol, $this->lifetimeCol, $this->timeCol) = (EXCLUDED.$this->dataCol, EXCLUDED.$this->lifetimeCol, EXCLUDED.$this->timeCol)"; |
|
break; |
|
default: |
|
// MERGE is not supported with LOBs: https://oracle.com/technetwork/articles/fuecks-lobs-095315.html |
|
return null; |
|
} |
|
|
|
$mergeStmt = $this->pdo->prepare($mergeSql); |
|
|
|
if ('sqlsrv' === $this->driver) { |
|
$mergeStmt->bindParam(1, $sessionId, \PDO::PARAM_STR); |
|
$mergeStmt->bindParam(2, $sessionId, \PDO::PARAM_STR); |
|
$mergeStmt->bindParam(3, $data, \PDO::PARAM_LOB); |
|
$mergeStmt->bindValue(4, time() + $maxlifetime, \PDO::PARAM_INT); |
|
$mergeStmt->bindValue(5, time(), \PDO::PARAM_INT); |
|
$mergeStmt->bindParam(6, $data, \PDO::PARAM_LOB); |
|
$mergeStmt->bindValue(7, time() + $maxlifetime, \PDO::PARAM_INT); |
|
$mergeStmt->bindValue(8, time(), \PDO::PARAM_INT); |
|
} else { |
|
$mergeStmt->bindParam(':id', $sessionId, \PDO::PARAM_STR); |
|
$mergeStmt->bindParam(':data', $data, \PDO::PARAM_LOB); |
|
$mergeStmt->bindValue(':expiry', time() + $maxlifetime, \PDO::PARAM_INT); |
|
$mergeStmt->bindValue(':time', time(), \PDO::PARAM_INT); |
|
} |
|
|
|
return $mergeStmt; |
|
} |
|
|
|
/** |
|
* Return a PDO instance. |
|
* |
|
* @return \PDO |
|
*/ |
|
protected function getConnection() |
|
{ |
|
if (null === $this->pdo) { |
|
$this->connect($this->dsn ?: \ini_get('session.save_path')); |
|
} |
|
|
|
return $this->pdo; |
|
} |
|
}
|
|
|