[Solved- 7 Answers] How to expire a PHP session after 30 minutes?

if (isset($_SESSION['LAST_ACTIVITY']) && (time() - $_SESSION['LAST_ACTIVITY'] > 1800)) {
 // last request was more than 30 minutes ago 
session_unset(); // unset $_SESSION variable for the run-time
session_destroy(); // destroy session data in storage }
$_SESSION['LAST_ACTIVITY'] = time(); // update last activity time stamp 

if (!isset($_SESSION['CREATED'])) { $_SESSION['CREATED'] = time(); } 
else if (time() - $_SESSION['CREATED'] > 1800) { // session started more than 30 minutes ago session_regenerate_id(true);
 // change session ID for the current session and invalidate old session ID
 $_SESSION['CREATED'] = time(); 
// update creation time } 

$_SESSION['example'] = array('foo' => 'bar', 'registered' => time());

 // later 

if ((time() - $_SESSION['example']['registered']) > (60 * 30))
 { 
unset($_SESSION['example']); 
} 

<IfModule mod_php5.c>
 #Session timeout php_value session.cookie_lifetime 1800 php_value session.gc_maxlifetime 1800 
</IfModule

if (isSet($_SESSION['started']))
{ if((mktime() - $_SESSION['started'] - 60*30) > 0){ 
Logout, destroy session, etc. 
} 
} 
else 
{ $_SESSION['started'] = mktime(); 
}

$lifetime = strtotime('+30 minutes', 0); session_set_cookie_params($lifetime); session_start(); 

$expiry = 1800 ;
//session expiry required after 30 mins 
if (isset($_SESSION['LAST']) && (time() - $_SESSION['LAST'] > $expiry))
 {
 session_unset(); 
session_destroy();
 } 
$_SESSION['LAST'] = time(); 

<?php
 $user = $_POST['user_name‘]
 $pass = $_POST['user_pass
require ('db_connection.php'); 
// Hey, always escape input if necessary!
 $result = mysql_query(sprintf("SELECT * FROM accounts WHERE user_Name='%s' AND user_Pass='%s'", mysql_real_escape_string($user), mysql_real_escape_string($pass)); 
if( mysql_num_rows( $result ) > 0)
 {
 $array = mysql_fetch_assoc($result);
 session_start();
 $_SESSION['user_id'] = $user;
 $_SESSION['login_time'] = time(); 
header("Location:loggedin.php");
 } 
Else
 { header("Location:login.php"); 
} 
?> 

<?php session_start();
 if( !isset( $_SESSION['user_id'] ) || time() - $_SESSION['login_time'] > 1800) 
{
 header("Location:login.php"); 
} 
else 
{ // uncomment the next line to refresh the session, so it will expire after thirteen minutes of inactivity, and not thirteen minutes after login //$_SESSION['login_time'] = time();
 echo ( "this session is ". $_SESSION['user_id'] ); 
//show rest of the page and all other content }
 ?>