session tutorial two_PHP tutorial

For other functions in PHPlib and the use of other functions related to session, you can refer to its manual, or go to its website to read online documentation. Its hometown is http://phplib.netuse.de/index.PHP3. Most of php4's session implementation is learned from phplib. It also relies on cookies to save session ids and uses the file system to save variables (by default). Therefore, its session variable cannot save the object (in fact, it can save the object content, but it is meaningless, because it is saved on the disk, not a living object, at best, it is an object corpse.) However, this limitation is not too big. , we only need to save variables in most cases. Of course, you can also save the session in the database. In the next section, we will talk about how to save the session in the database. Since php4 has more session support than php3, there are also more session configuration options in the PHP.ini file. Let’s take a look at the functions and meanings of each item:

[session]
session.save_handler = files; handler used to store/retrieve data (what to use to save session variables, files are used by default)
session.save_path = c:/temp; argument passed to save_handler (the directory where session variables are saved, /tmp under linux/unix, set to your directory under win)
; in the case of files, this is the
; path where data files are stored
session.use_cookies = 1; whether to use cookies (whether to use cookies, of course, there is no choice under win)
session.name = PHPSESSID
; name of the session (the cookie name used by the default session, it is recommended not to change it)
; is used as cookie name
session.auto_start = 0; initialize session on request startup (whether to automatically enable session, when it is 1, there is no need to call the session_start() function in each page)
session.cookie_lifetime = 0 ; lifetime in seconds of cookie (Set the storage time of the cookie after it is sent to the browser, in seconds. The default value is 0, which means until the browser is closed.)
; or if 0, until browser is restarted
session.cookie_path = / ; the path the cookie is valid for(cookie)(cookies valid path)
session.cookie_domain = ; the domain the cookie is valid for (cookies valid domain name)
session.serialize_handler = php; handler used to serialize data (defines the identifier of serialized data. This function is only used internally by the WDDX module or PHP. The default value is PHP)
; php is the standard serializer of PHP
session.gc_probability = 1 ; percent probability that the (Set the processing probability every time a temporary file starts processing (gc, garbage collection). The default value is 1. )
; 'garbage collection' process is started
; on every session initialization
session.gc_maxlifetime = 1440; after this number of seconds, stored(Sets the number of seconds to survive before the temporary file saving the session is cleared)
; data will be seen as 'garbage' and
; cleaned up by the gc process
session.referer_check = ; check HTTP Referer to invalidate (Decide whether the session code referring to the client should be deleted. Sometimes it is set not to be deleted for security or other considerations. The default value is 0.)
; externally stored URLs containing ids
session.entropy_length = 0; how many bytes to read from the file (Set the number of bits that session reads from high-entropy resources. The default value is 0.)
session.entropy_file = ; specified here to create the session id (When setting the session code to create, use external high-entropy resources or files to create, such as /dev/random or /dev/urandom on UNIX systems. )
; session.entropy_length = 16
; session.entropy_file = /dev/urandom
session.cache_limiter = nocache; set to { nocache,private,public} to (set session buffer limit)
; determine HTTP caching aspects
session.cache_expire = 180; document expires after n minutes (document validity period, unit is minutes)

Under the Windows platform, versions before php4.01pl2 will cause an error after setting session.save_path. This is a bug in PHP that has been corrected in php4.01pl2 and later. If you use a previous version, you can set session.save_path to "./" or "/temp", and create a directory named temp in the root directory of the current disk where you place the php script ( My PHP script is placed under d:apachehtdocs, then I create a directory called temp in the root directory of the d: drive).
The session-related functions in PHP4 mainly include the following:

session_start: Initialize the session and need to be called at the beginning of each page of the session.
session_destroy: End session, called when the session needs to be ended.
session_name: access the current session name.
session_module_name: access the current session module.
session_save_path: access the current session path.
session_id: access the current session id number.
session_register: Register new session variables.
session_unregister: Delete registered session variables.
session_is_registered: Check whether the session variable is registered.
session_decode: session data decoding.
session_encode: session data encryption.

Normally we only need to call three functions.
That is, session_start(), session_register(), session_is_registered().
Call the session_start() function at the beginning of each page that requires session,
A typical page using session is as follows:


....

$var="hello";
session_register("var");//Register $var variable, note that there is no $ symbol

if(session_is_registered("var"))//Check whether the variable is registered
echo "haha, registered!";
else
echo "sorry, not registered yet!";

?>

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