function PdoSessionHandler::doWrite

Overrides AbstractSessionHandler::doWrite

File

vendor/symfony/http-foundation/Session/Storage/Handler/PdoSessionHandler.php, line 330

Class

PdoSessionHandler

Session handler using a PDO connection to read and write data.

Namespace

Symfony\Component\HttpFoundation\Session\Storage\Handler

Code

protected function doWrite(string $sessionId, string $data) : bool {
    $maxlifetime = (int) (($this->ttl instanceof \Closure ? ($this->ttl)() : $this->ttl) ?? \ini_get('session.gc_maxlifetime'));
    try {
        // We use a single MERGE SQL query when supported by the database.
        $mergeStmt = $this->getMergeStatement($sessionId, $data, $maxlifetime);
        if (null !== $mergeStmt) {
            $mergeStmt->execute();
            return true;
        }
        $updateStmt = $this->getUpdateStatement($sessionId, $data, $maxlifetime);
        $updateStmt->execute();
        // When MERGE is not supported, like in Postgres < 9.5, we have to use this approach that can result in
        // duplicate key errors when the same session is written simultaneously (given the LOCK_NONE behavior).
        // We can just catch such an error and re-execute the update. This is similar to a serializable
        // transaction with retry logic on serialization failures but without the overhead and without possible
        // false positives due to longer gap locking.
        if (!$updateStmt->rowCount()) {
            try {
                $insertStmt = $this->getInsertStatement($sessionId, $data, $maxlifetime);
                $insertStmt->execute();
            } catch (\PDOException $e) {
                // Handle integrity violation SQLSTATE 23000 (or a subclass like 23505 in Postgres) for duplicate keys
                if (str_starts_with($e->getCode(), '23')) {
                    $updateStmt->execute();
                }
                else {
                    throw $e;
                }
            }
        }
    } catch (\PDOException $e) {
        $this->rollback();
        throw $e;
    }
    return true;
}