php--Session and its usage

The session mechanism (Session) is used in PHP to save some data in concurrent access. This can help create a more user-friendly program and increase the appeal of the site.

A visitor to your web site will be assigned a unique id, which is the so-called session id. This id can be stored in a cookie on the user side or passed through the URL.

Session support allows you to request The data in is stored in the superglobal array $_SESSION. When a visitor visits your site, PHP will check automatically (if session.auto_start is set to 1) or at your request (explicitly via session_start() or implicitly Via session_register()) whether the current session id was created by a previously sent request. If this is the case, then the previously saved environment will be rebuilt.

$_SESSION (and all registered variables) will be used by PHP using the built-in sequence The serialization method is serialized when the request is completed. The serialization method can be set to a specified method through the session.serialize_handler PHP configuration option. Registered variables that are not defined will be marked as undefined. During concurrent access, these variables are not Will be defined by the session module unless the user later defines them.

Because session data is serialized, resource variables cannot be stored in the session. Serialization handles (php and php_binary) will be limited by register_globals. Also, numeric indexes Or the special characters (| and !) contained in the string index cannot be used. When using these characters to close the script execution, an error will occur at the end. php_serialize has no such restriction. php_serialize is available from PHP 5.5.4 onwards.

Example 1, SESSION's simple use:

<?php
//注册session
session_start();
if (!isset($_SESSION[&#39;count&#39;])) {
    $_SESSION[&#39;count&#39;] = 0;
} else {
    $_SESSION[&#39;count&#39;]++;
}
//删除session
unset($_SESSION[&#39;count&#39;]);
?>

session related functions:

Sactive_cache_expire — Return Cache Expire

session_Cache_limiter — Get AND/OR CURRENT CACHE Terisession_Commit - Session_write_Close's aliases

Session_DECODE -DECODES Session data from a session encoded string

session_destroy — Destroys all data registered to a session

session_encode — Encode the current session data into a string

session_get_cookie_params — Get the session cookie parameters

session_id — Get and/or set the current session id

session_is_registered — Check if the variable has been registered in the session

session_module_name — Get and/or set the current session module

session_name — Get and/or set the current session name

session_regenerate_id — Update the current session id with a newly generated one

session_register_shutdown — Session shutdown function

session_register — Register one or more global variables with the current session

session_save_path — Get and/or set the current session save path

session_set_cookie_params — Set the session cookie parameters

session_set_save_handler — Sets user -level session storage functions

session_start — Start new or resume existing session

session_status — Returns the current session status

session_unregister — Unregister a global variable from the current session

session_unset — Free all session variables

session_write_close — Write session data and end session