<?php  if (!defined('BASEPATH')) exit('No direct script access allowed');

/**

 * CodeIgniter

 *

 * An open source application development framework for PHP 4.3.2 or newer

 *

 * @package		CodeIgniter

 * @author		Rick Ellis

 * @copyright	Copyright (c) 2006, EllisLab, Inc.

 * @license		http://www.codeignitor.com/user_guide/license.html

 * @link		http://www.codeigniter.com

 * @since		Version 1.0

 * @filesource

 */



// ------------------------------------------------------------------------



/**

 * Session Class

 *

 * @package		CodeIgniter

 * @subpackage	Libraries

 * @category	Sessions

 * @author		Rick Ellis

 * @link		http://www.codeigniter.com/user_guide/libraries/sessions.html

 */

class CI_Session {



	var $CI;

	var $now;

	var $encryption		= TRUE;

	var $use_database	= FALSE;

	var $session_table	= FALSE;

	var $sess_length	= 7200;

	var $sess_cookie	= 'ci_session';

	var $userdata		= array();

	var $gc_probability	= 5;





	/**

	 * Session Constructor

	 *

	 * The constructor runs the session routines automatically

	 * whenever the class is instantiated.

	 */		

	function CI_Session()

	{

		$this->CI =& get_instance();



		log_message('debug', "Session Class Initialized");

		$this->sess_run();

	}

	

	// --------------------------------------------------------------------

	

	/**

	 * Run the session routines

	 *

	 * @access	public

	 * @return	void

	 */		

	function sess_run()

	{

		/*

		 *  Set the "now" time

		 *

		 * It can either set to GMT or time(). The pref

		 * is set in the config file.  If the developer

		 * is doing any sort of time localization they

		 * might want to set the session time to GMT so

		 * they can offset the "last_activity" and

		 * "last_visit" times based on each user's locale.

		 *

		 */

		if (strtolower($this->CI->config->item('time_reference')) == 'gmt')

		{

			$now = time();

			$this->now = mktime(gmdate("H", $now), gmdate("i", $now), gmdate("s", $now), gmdate("m", $now), gmdate("d", $now), gmdate("Y", $now));

	

			if (strlen($this->now) < 10)

			{

				$this->now = time();

				log_message('error', 'The session class could not set a proper GMT timestamp so the local time() value was used.');

			}

		}

		else

		{

			$this->now = time();

		}

		

		/*

		 *  Set the session length

		 *

		 * If the session expiration is set to zero in

		 * the config file we'll set the expiration

		 * two years from now.

		 *

		 */

		$expiration = $this->CI->config->item('sess_expiration');

		

		if (is_numeric($expiration))

		{

			if ($expiration > 0)

			{

				$this->sess_length = $this->CI->config->item('sess_expiration');

			}

			else

			{

				$this->sess_length = (60*60*24*365*2);

			}

		}

		

		// Do we need encryption?

		$this->encryption = $this->CI->config->item('sess_encrypt_cookie');

	

		if ($this->encryption == TRUE)	

		{

			$this->CI->load->library('encrypt');

		}		



		// Are we using a database?

		if ($this->CI->config->item('sess_use_database') === TRUE AND $this->CI->config->item('sess_table_name') != '')

		{

			$this->use_database = TRUE;

			$this->session_table = $this->CI->config->item('sess_table_name');

			$this->CI->load->database();

		}

		

		// Set the cookie name

		if ($this->CI->config->item('sess_cookie_name') != FALSE)

		{

			$this->sess_cookie = $this->CI->config->item('cookie_prefix').$this->CI->config->item('sess_cookie_name');

		}

	

		/*

		 *  Fetch the current session

		 *

		 * If a session doesn't exist we'll create

		 * a new one.  If it does, we'll update it.

		 *

		 */

		if ( ! $this->sess_read())

		{

			$this->sess_create();

		}

		else

		{	

			// We only update the session every five minutes

			if (($this->userdata['last_activity'] + 300) < $this->now)

			{

				$this->sess_update();

			}

		}

		

		// Delete expired sessions if necessary

		if ($this->use_database === TRUE)

		{		

			$this->sess_gc();

		}	

	}

	

	// --------------------------------------------------------------------

	

	/**

	 * Fetch the current session data if it exists

	 *

	 * @access	public

	 * @return	void

	 */

	function sess_read()

	{	

		// Fetch the cookie

		$session = $this->CI->input->cookie($this->sess_cookie);

		

		if ($session === FALSE)

		{

			log_message('debug', 'A session cookie was not found.');

			return FALSE;

		}

		

		// Decrypt and unserialize the data

		if ($this->encryption == TRUE)

		{

			$session = $this->CI->encrypt->decode($session);

		}



		$session = @unserialize($this->strip_slashes($session));

		

		if ( ! is_array($session) OR ! isset($session['last_activity']))

		{

			log_message('error', 'The session cookie data did not contain a valid array. This could be a possible hacking attempt.');

			return FALSE;

		}

		

		// Is the session current?

		if (($session['last_activity'] + $this->sess_length) < $this->now)

		{

			$this->sess_destroy();

			return FALSE;

		}



		// Does the IP Match?

		if ($this->CI->config->item('sess_match_ip') == TRUE AND $session['ip_address'] != $this->CI->input->ip_address())

		{

			$this->sess_destroy();

			return FALSE;

		}

		

		// Does the User Agent Match?

		if ($this->CI->config->item('sess_match_useragent') == TRUE AND $session['user_agent'] != substr($this->CI->input->user_agent(), 0, 50))

		{

			$this->sess_destroy();

			return FALSE;

		}

		

		// Is there a corresponding session in the DB?

		if ($this->use_database === TRUE)

		{

			$this->CI->db->where('session_id', $session['session_id']);

					

			if ($this->CI->config->item('sess_match_ip') == TRUE)

			{

				$this->CI->db->where('ip_address', $session['ip_address']);

			}



			if ($this->CI->config->item('sess_match_useragent') == TRUE)

			{

				$this->CI->db->where('user_agent', $session['user_agent']);

			}

			

			$query = $this->CI->db->get($this->session_table);



			if ($query->num_rows() == 0)

			{

				$this->sess_destroy();

				return FALSE;

			}

			else

			{

				$row = $query->row();

				if (($row->last_activity + $this->sess_length) < $this->now)

				{

					$this->CI->db->where('session_id', $session['session_id']);

					$this->CI->db->delete($this->session_table);

					$this->sess_destroy();

					return FALSE;

				}

			}

		}

	

		// Session is valid!

		$this->userdata = $session;

		unset($session);

		

		return TRUE;

	}

	

	// --------------------------------------------------------------------

	

	/**

	 * Write the session cookie

	 *

	 * @access	public

	 * @return	void

	 */

	function sess_write()

	{								

		$cookie_data = serialize($this->userdata);

		

		if ($this->encryption == TRUE)

		{

			$cookie_data = $this->CI->encrypt->encode($cookie_data);

		}



		setcookie(

					$this->sess_cookie,

					$cookie_data,

					$this->sess_length + time(),

					$this->CI->config->item('cookie_path'),

					$this->CI->config->item('cookie_domain'),

					0

				);

	}

	

	// --------------------------------------------------------------------

	

	/**

	 * Create a new session

	 *

	 * @access	public

	 * @return	void

	 */

	function sess_create()

	{	

		$sessid = '';

		while (strlen($sessid) < 32)

		{

			$sessid .= mt_rand(0, mt_getrandmax());

		}

	

		$this->userdata = array(

							'session_id' 	=> md5(uniqid($sessid, TRUE)),

							'ip_address' 	=> $this->CI->input->ip_address(),

							'user_agent' 	=> substr($this->CI->input->user_agent(), 0, 50),

							'last_activity'	=> $this->now

							);

		

		

		// Save the session in the DB if needed

		if ($this->use_database === TRUE)

		{

			$this->CI->db->query($this->CI->db->insert_string($this->session_table, $this->userdata));

		}

			

		// Write the cookie

		$this->userdata['last_visit'] = 0;		

		$this->sess_write();

	}

	

	// --------------------------------------------------------------------

	

	/**

	 * Update an existing session

	 *

	 * @access	public

	 * @return	void

	 */

	function sess_update()

	{	

		if (($this->userdata['last_activity'] + $this->sess_length) < $this->now)

		{

			$this->userdata['last_visit'] = $this->userdata['last_activity'];

		}

	

		$this->userdata['last_activity'] = $this->now;

		

		// Update the session in the DB if needed

		if ($this->use_database === TRUE)

		{		

			$this->CI->db->query($this->CI->db->update_string($this->session_table, array('last_activity' => $this->now), array('session_id' => $this->userdata['session_id'])));

		}

		

		// Write the cookie

		$this->sess_write();

	}

	

	// --------------------------------------------------------------------

	

	/**

	 * Destroy the current session

	 *

	 * @access	public

	 * @return	void

	 */

	function sess_destroy()

	{

		setcookie(

					$this->sess_cookie,

					addslashes(serialize(array())),

					($this->now - 31500000),

					$this->CI->config->item('cookie_path'),

					$this->CI->config->item('cookie_domain'),

					0

				);

	}

	

	// --------------------------------------------------------------------

	

	/**

	 * Garbage collection

	 *

	 * This deletes expired session rows from database

	 * if the probability percentage is met

	 *

	 * @access	public

	 * @return	void

	 */

	function sess_gc()

	{

		srand(time());

		if ((rand() % 100) < $this->gc_probability)

		{

			$expire = $this->now - $this->sess_length;

			

			$this->CI->db->where("last_activity < {$expire}");

			$this->CI->db->delete($this->session_table);



			log_message('debug', 'Session garbage collection performed.');

		}

	}

	

	// --------------------------------------------------------------------

	

	/**

	 * Fetch a specific item form  the session array

	 *

	 * @access	public

	 * @param	string

	 * @return	string

	 */		

	function userdata($item)

	{

		return ( ! isset($this->userdata[$item])) ? FALSE : $this->userdata[$item];

	}

	

	// --------------------------------------------------------------------

	

	/**

	 * Add or change data in the "userdata" array

	 *

	 * @access	public

	 * @param	mixed

	 * @param	string

	 * @return	void

	 */		

	function set_userdata($newdata = array(), $newval = '')

	{

		if (is_string($newdata))

		{

			$newdata = array($newdata => $newval);

		}

	

		if (count($newdata) > 0)

		{

			foreach ($newdata as $key => $val)

			{

				$this->userdata[$key] = $val;

			}

		}

	

		$this->sess_write();

	}

	

	// --------------------------------------------------------------------

	

	/**

	 * Delete a session variable from the "userdata" array

	 *

	 * @access	array

	 * @return	void

	 */		

	function unset_userdata($newdata = array())

	{

		if (is_string($newdata))

		{

			$newdata = array($newdata => '');

		}

	

		if (count($newdata) > 0)

		{

			foreach ($newdata as $key => $val)

			{

				unset($this->userdata[$key]);

			}

		}

	

		$this->sess_write();

	}

	

	// --------------------------------------------------------------------

	

	/**

	 * Strip slashes

	 *

	 * @access	public

	 * @param	mixed

	 * @return	mixed

	 */

	 function strip_slashes($vals)

	 {

	 	if (is_array($vals))

	 	{	

	 		foreach ($vals as $key=>$val)

	 		{

	 			$vals[$key] = $this->strip_slashes($val);

	 		}

	 	}

	 	else

	 	{

	 		$vals = stripslashes($vals);

	 	}

	 	

	 	return $vals;

	}



}

// END Session Class

?>