How to prevent auto logout in codeigniter?

You are probably performing ajax requests, this is a common issue...

I would suggest you to use session database and make ajax calls is to not update the session...

Make this on you session class

class MY_Session extends CI_Session {public function sess_update(){    $CI =& get_instance();    if ( ! $CI->input->is_ajax_request())    {        parent::sess_update();    }}}

Create a session library with your own MY_Session.php library that overwrote the sess_update method with one that only executed the update method when not an AJAX request:

MY_Session.php

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');require_once BASEPATH . '/libraries/Session.php';class MY_Session extends CI_Session{    function __construct()    {        parent::__construct();        $this->CI->session = $this;    }    function sess_update()    {        // Do NOT update an existing session on AJAX calls.        if (!$this->CI->input->is_ajax_request())            return parent::sess_update();    }}

Location of file:

/application/libraries/MY_Session.php */

You can either auto-load this library from config/autoload.php:

$autoload['libraries'] = array( 'MY_Session');

Or, you can load it later:

$this->load->library('MY_Session');

What this sess_update(); does?

In your system/libraries/Session.php there is a function sess_update() that automatically update your last activity.This function update the session every five minutes by default.

public function sess_update()    {        // We only update the session every five minutes by default        if (($this->userdata['last_activity'] + $this->sess_time_to_update) >= $this->now)        {            return;        }        // _set_cookie() will handle this for us if we aren't using database sessions        // by pushing all userdata to the cookie.        $cookie_data = NULL;        /* Changing the session ID during an AJAX call causes problems,         * so we'll only update our last_activity         */        if ($this->CI->input->is_ajax_request())        {            $this->userdata['last_activity'] = $this->now;            // Update the session ID and last_activity field in the DB if needed            if ($this->sess_use_database === TRUE)            {                // set cookie explicitly to only have our session data                $cookie_data = array();                foreach (array('session_id','ip_address','user_agent','last_activity') as $val)                {                    $cookie_data[$val] = $this->userdata[$val];                }                $this->CI->db->query($this->CI->db->update_string($this->sess_table_name,                                            array('last_activity' => $this->userdata['last_activity']),                                            array('session_id' => $this->userdata['session_id'])));            }            return $this->_set_cookie($cookie_data);        }        // Save the old session id so we know which record to        // update in the database if we need it        $old_sessid = $this->userdata['session_id'];        $new_sessid = '';        do        {            $new_sessid .= mt_rand(0, mt_getrandmax());        }        while (strlen($new_sessid) < 32);        // To make the session ID even more secure we'll combine it with the user's IP        $new_sessid .= $this->CI->input->ip_address();        // Turn it into a hash and update the session data array        $this->userdata['session_id'] = $new_sessid = md5(uniqid($new_sessid, TRUE));        $this->userdata['last_activity'] = $this->now;        // Update the session ID and last_activity field in the DB if needed        if ($this->sess_use_database === TRUE)        {            // set cookie explicitly to only have our session data            $cookie_data = array();            foreach (array('session_id','ip_address','user_agent','last_activity') as $val)            {                $cookie_data[$val] = $this->userdata[$val];            }            $this->CI->db->query($this->CI->db->update_string($this->sess_table_name, array('last_activity' => $this->now, 'session_id' => $new_sessid), array('session_id' => $old_sessid)));        }        // Write the cookie        $this->_set_cookie($cookie_data);    }

Replace line 346 in system/libraries/Session.php (function sess_update())

if (($this->userdata['last_activity'] + $this->sess_time_to_update) >= $this->now)

With:

if (($this->userdata['last_activity'] + $this->sess_time_to_update) >= $this->now || $this->CI->input->is_ajax_request())

hope this works for you .