Detailed explanation of how to use the php session() function_PHP tutorial

The php session() function plays a very important role in PHP development applications. Let me give beginners a brief introduction to the usage and examples of the php session() function.

Compared with Cookie, Session is a session stored on the server side, which is relatively safe and does not have storage length limit like Cookie. This article briefly introduces the use of Session.
Since the Session is stored on the server side in the form of a text file, the client is not afraid of modifying the Session content. In fact, in the session file on the server side, PHP automatically modifies the permissions of the session file, retaining only system read and write permissions, and cannot be modified through ftp, so it is much safer.

Since the Session is stored on the server side in the form of a text file, the client is not afraid of modifying the contents of the Session. In fact, in the Session file on the server side, PHP automatically modifies the permissions of the Session file, retaining only system read and write permissions, and cannot be modified through ftp, so it is much safer.

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代码如下

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// 启动Session session_start(); // 声明一个名为 admin 的变量，并赋空值。 $_SESSION["admin"] = null; ?>  // 启动Session session_start(); // 将原来注册的某个变量销毁 unset($_SESSION['admin']); // 销毁整个 Session 文件 session_destroy(); ?>  // 启动Session session_start(); // 保存一天 $lifeTime = 24 * 3600; setcookie(session_name(), session_id(), time() + $lifeTime, "/"); ?>  // 保存一天 $lifeTime = 24 * 3600; session_set_cookie_params($lifeTime); session_start(); $_SESSION["admin"] = true; ?>  // 保存一天 $lifeTime = 24 * 3600; // 取得当前 Session 名，默认为 PHPSESSID $sessionName = session_name(); // 取得 Session ID $sessionID = $_GET[$sessionName]; // 使用 session_id() 设置获得的 Session ID session_id($sessionID); session_set_cookie_params($lifeTime); session_start(); $_SESSION['admin'] = true; ?>  // 设置一个存放目录 $savePath = './session_save_dir/'; // 保存一天 $lifeTime = 24 * 3600; session_save_path($savePath); session_set_cookie_params($lifeTime); session_start(); $_SESSION['admin'] = true; ?>

// Start Session session_start();

//Declare a variable named admin and assign it a null value.
$_SESSION["admin"] = null; ?>

// Start Session
session_start(); // Destroy a previously registered variable

unset($_SESSION['admin']);

// Destroy the entire Session file

session_destroy();

?>

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 session_start();
 echo session_id();
 // 输出 dqr58dnuqj2gufvg4o3tmjb9v4
?>

// Start Session

session_start();

// Save for one day

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session_id("NowaMagic");  session_start();    echo session_id();  // 输出 NowaMagic ?>

$lifeTime = 24 * 3600; setcookie(session_name(), session_id(), time() + $lifeTime, "/"); ?> // Save for one day $lifeTime = 24 * 3600; session_set_cookie_params($lifeTime); session_start(); $_SESSION["admin"] = true; ?> // Save for one day $lifeTime = 24 * 3600; // Get the current Session name, the default is PHPSESSID $sessionName = session_name(); // Get Session ID $sessionID = $_GET[$sessionName]; // Use session_id() to set the obtained Session ID session_id($sessionID); session_set_cookie_params($lifeTime); session_start(); $_SESSION['admin'] = true; ?> //Set a storage directory $savePath = './session_save_dir/'; // Save for one day $lifeTime = 24 * 3600; session_save_path($savePath); session_set_cookie_params($lifeTime); session_start(); $_SESSION['admin'] = true; ?> In addition, we can also use the session_set_save_handler function to customize the calling method of Session. Complete PHP function: session_id() session_id() session_id() accesses the current session code. Syntax: string session_id(string [id]); This function can obtain or reconfigure the codename of the currently stored Session. If there is no parameter id, it means that only the current Session code can be obtained. Adding the parameter means setting the Session code to the newly specified id. Input and return are both strings. Output session_id()

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session_start(); echo session_id(); // Output dqr58dnuqj2gufvg4o3tmjb9v4 ?>

Set session_id()

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session_id("NowaMagic"); session_start(); echo session_id(); // Output NowaMagic ?>

session_id restores session content
PHP sessions can be restored programmatically, which is different from Java. The session recovery mechanism can realize the sharing of multiple application sessions, because PHP sessions are stored in the form of files or databases. First, the session_id is obtained through the session_id() function, and this value can be passed.

When the program restores the session, you must first know the session_id. You can know from the manual that the session is restored through session_id($id); but when restoring, you must pay attention to the order. To get the content of the previous session, it must be before session_start() Execute session_id($id) so that you can restore the previous content when initializing the session when session_start is executed. Otherwise, you will get an empty session and you will get nothing. The session was reinitialized before. This is closely related to the function of session_start(), because session_start tells PHP that the session needs to be initialized and the session content needs to be deserialized from the session file, so the function of session_start is to deserialize the previously stored file content. You must know the session_id before session_start serialization. If not, generate a new session_id. If so, deserialize the contents of the corresponding file.

http://www.bkjia.com/PHPjc/628625.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/628625.htmlTechArticleThe php session() function plays a very important role in PHP development applications. Let me give it to beginners. Let’s briefly introduce the usage methods and examples of the php session() function. Compared to Coo...