Starting a PHP Session
A
PHP session is easily started by making a call to the session_start() function.This
function first checks if a session is already started and if none is started
then it starts one. It is recommended to put the call to session_start() at
the beginning of the page. Session
variables are stored in associative array called $_SESSION[]. These
variables can be accessed during lifetime of a session. The
following example starts a session then registers a variable called counter
that is incremented each time the page is visited during the session. Make
use of isset() function to check if session variable is
already set or not. Put
this code in a test.php file and
load this file many times to see the result −
eg:-<?php
session_start();
if( isset( $_SESSION['counter'] ) )
{
$_SESSION['counter'] += 1;
}
else
{
$_SESSION['counter'] = 1;
}
$msg = "You have visited this page ". $_SESSION['counter'];
$msg .= "in this session.";
?>
<html>
<head>
<title>Setting up a PHP session</title>
</head>
<body>
<?php echo ( $msg ); ?>
</body>
</html>
It will produce the following result −
You have visited this page 1in this session.
Destroying a PHP Session
A PHP session can be destroyed by session_destroy() function. This function does not need any argument and a single call can destroy all the session variables. If you want to destroy a single session variable then you can use unset() function to unset a session variable.
Here is the example to unset a single variable −
<?php
unset($_SESSION['counter']);
?>
Here is the call which will destroy all the session variables −
<?php
session_destroy();
?>
Turning on Auto Session
You don't need to call start_session() function to start a session when a user visits your site if you can set session.auto_start variable to 1 in php.ini file.
https://www.youtube.com/channel/UCKLRUr6U5OFeu7FLOpQ-FSw/videos
eg:-<?php
session_start();
if( isset( $_SESSION['counter'] ) )
{
$_SESSION['counter'] += 1;
}
else
{
$_SESSION['counter'] = 1;
}
$msg = "You have visited this page ". $_SESSION['counter'];
$msg .= "in this session.";
?>
<html>
<head>
<title>Setting up a PHP session</title>
</head>
<body>
<?php echo ( $msg ); ?>
</body>
</html>
It will produce the following result −
You have visited this page 1in this session.
Destroying a PHP Session
A PHP session can be destroyed by session_destroy() function. This function does not need any argument and a single call can destroy all the session variables. If you want to destroy a single session variable then you can use unset() function to unset a session variable.
Here is the example to unset a single variable −
<?php
unset($_SESSION['counter']);
?>
Here is the call which will destroy all the session variables −
<?php
session_destroy();
?>
Turning on Auto Session
You don't need to call start_session() function to start a session when a user visits your site if you can set session.auto_start variable to 1 in php.ini file.
https://www.youtube.com/channel/UCKLRUr6U5OFeu7FLOpQ-FSw/videos
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