Working with PHP Sessions
Written by Saran on July 29, 2012, Updated August 20, 2016How PHP Session Works?
PHP $_SESSION creates unique id for each user, there unique ids are stored in cookie and sometimes in URLs. However; the session data is stored in the server, even if there are hundred of users accessing the site, PHP session can exactly identify each user and serve them stored data, and it is considered safe too, because session information are not accessible from the client browser, and there are no easy way to hijack a session from remote computer.Starting PHP Session
To start PHP session, we use session_start() function. It must be on the top of HTML or any text. Something like this :PHP
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<?php
session_start(); // starts PHP session
//other PHP codes and HTML
?>
<HTML>
</HTML>Storing & Retrieving Session variables
When the session is active, we can store values in PHP $_SESSION, later which can be accessed from any PHP script.PHP
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<?php
// starts PHP session
session_start();
//store a session variable
$_SESSION["name"] = "Saaraan";
//storing array variables
$_SESSION["arr"] = array('name' => 'saaraan', 'url' => 'http://www.sanwebe.com', 'type'=> 'blog');
//retrieve and output stored session variable
echo $_SESSION["name"];
?>PHP
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<?php
// start or resume PHP session
session_start();
//retrieve and output stored session variable
echo $_SESSION["name"];
//retrieve array vars
print_r($_SESSION["arr"]);
?>Removing or Destroying PHP $_SESSIONS
It is better to remove session variables when they are no longer needed, to remove certain variables we can use PHP unset().PHP
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<?php
//removes variable called name
unset($_SESSION["name"]);
?>PHP
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<?php
//destroy everything
session_destroy();
?>
