SessionHandler::write

Function name: SessionHandler::write()

Applicable version: PHP 5 >= 5.4.0, PHP 7

Function description: The SessionHandler::write() method is used to write session data. This method is implemented by the session handler class and is used to save session data to persistent storage.

Syntax: SessionHandler::write(string $session_id, string $session_data): bool

parameter:

• $session_id: Session ID, is a unique identifier generated by the server.
• $session_data: session data, is a serialized string.

Return value:

• Returns true on success, and false on failure.

Example:

 <?php class MySessionHandler implements SessionHandlerInterface { // 实现SessionHandlerInterface 接口中的write 方法public function write($session_id, $session_data) { // 将会话数据保存到数据库或其他持久存储中// 假设这里使用数据库存储会话数据$db = new PDO('mysql:host=localhost;dbname=mydatabase', 'username', 'password'); $stmt = $db->prepare("INSERT INTO sessions (session_id, session_data) VALUES (:session_id, :session_data)"); $stmt->bindParam(':session_id', $session_id); $stmt->bindParam(':session_data', $session_data); return $stmt->execute(); } } // 设置自定义的会话处理程序$handler = new MySessionHandler(); session_set_save_handler($handler, true); // 启动会话session_start(); // 修改会话数据$_SESSION['username'] = 'john'; // 手动调用write 方法将会话数据写入持久存储session_write_close(); ?>

In the above example, we customize a session handler class MySessionHandler and implement the write method in the SessionHandlerInterface interface. In the write method, we use PDO to connect to the database and insert the session ID and session data into the sessions table.

We then set the custom session handler to the handler of the current session through the session_set_save_handler() function. Next, we start the session and modify the session data. Finally, the write method is manually called by calling the session_write_close() method, and the session data is written to the persistent storage.

Note that using a custom session handler requires calling session_set_save_handler() before session_start(). Additionally, if using a custom session handler, make sure to call the session_write_close() method before the script ends to ensure that session data is written to the persistent storage.