<?php if ( ! defined(‘BASEPATH‘)) exit(‘No direct script access allowed‘);/** * CodeIgniter * * An open source application development framework for PHP 5.1.6 or newer * * @package CodeIgniter * @author EllisLab Dev Team * @copyright Copyright (c) 2008 - 2014, EllisLab, Inc. * @copyright Copyright (c) 2014 - 2015, British Columbia Institute of Technology (http://bcit.ca/) * @license http://codeigniter.com/user_guide/license.html * @link http://codeigniter.com * @since Version 1.0 * @filesource */// ------------------------------------------------------------------------/** * Session Class * * @package CodeIgniter * @subpackage Libraries * @category Sessions * @author EllisLab Dev Team * @link http://codeigniter.com/user_guide/libraries/sessions.html */class CI_Session { var $sess_encrypt_cookie = FALSE; var $sess_use_database = FALSE; var $sess_table_name = ‘‘; var $sess_expiration = 7200; var $sess_expire_on_close = FALSE; var $sess_match_ip = FALSE; var $sess_match_useragent = TRUE; var $sess_cookie_name = ‘ci_session‘; var $cookie_prefix = ‘‘; var $cookie_path = ‘‘; var $cookie_domain = ‘‘; var $cookie_secure = FALSE; var $sess_time_to_update = 300; var $encryption_key = ‘‘; var $flashdata_key = ‘flash‘; var $time_reference = ‘time‘; var $gc_probability = 5; var $userdata = array(); var $CI; var $now; /** * Session Constructor * * The constructor runs the session routines automatically * whenever the class is instantiated. */ public function __construct($params = array()) { log_message(‘debug‘, "Session Class Initialized"); // Set the super object to a local variable for use throughout the class $this->CI =& get_instance(); // Set all the session preferences, which can either be set // manually via the $params array above or via the config file foreach (array(‘sess_encrypt_cookie‘, ‘sess_use_database‘, ‘sess_table_name‘, ‘sess_expiration‘, ‘sess_expire_on_close‘, ‘sess_match_ip‘, ‘sess_match_useragent‘, ‘sess_cookie_name‘, ‘cookie_path‘, ‘cookie_domain‘, ‘cookie_secure‘, ‘sess_time_to_update‘, ‘time_reference‘, ‘cookie_prefix‘, ‘encryption_key‘) as $key) { $this->$key = (isset($params[$key])) ? $params[$key] : $this->CI->config->item($key); } if ($this->encryption_key == ‘‘) { show_error(‘In order to use the Session class you are required to set an encryption key in your config file.‘); } // Load the string helper so we can use the strip_slashes() function $this->CI->load->helper(‘string‘); // Do we need encryption? If so, load the encryption class if ($this->sess_encrypt_cookie == TRUE) { $this->CI->load->library(‘encrypt‘); } // Are we using a database? If so, load it if ($this->sess_use_database === TRUE AND $this->sess_table_name != ‘‘) { $this->CI->load->database(); } // Set the "now" time. Can either be GMT or server time, based on the // config prefs. We use this to set the "last activity" time $this->now = $this->_get_time(); // Set the session length. If the session expiration is // set to zero we‘ll set the expiration two years from now. if ($this->sess_expiration == 0) { $this->sess_expiration = (60*60*24*365*2); } // Set the cookie name $this->sess_cookie_name = $this->cookie_prefix.$this->sess_cookie_name; // Run the Session routine. 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 { $this->sess_update(); } // Delete ‘old‘ flashdata (from last request) $this->_flashdata_sweep(); // Mark all new flashdata as old (data will be deleted before next request) $this->_flashdata_mark(); // Delete expired sessions if necessary $this->_sess_gc(); log_message(‘debug‘, "Session routines successfully run"); } // -------------------------------------------------------------------- /** * Fetch the current session data if it exists * * @access public * @return bool */ function sess_read() { // Fetch the cookie $session = $this->CI->input->cookie($this->sess_cookie_name); // No cookie? Goodbye cruel world!... if ($session === FALSE) { log_message(‘debug‘, ‘A session cookie was not found.‘); return FALSE; } // HMAC authentication $len = strlen($session) - 40; if ($len <= 0) { log_message(‘error‘, ‘Session: The session cookie was not signed.‘); return FALSE; } // Check cookie authentication $hmac = substr($session, $len); $session = substr($session, 0, $len); // Time-attack-safe comparison $hmac_check = hash_hmac(‘sha1‘, $session, $this->encryption_key); $diff = 0; for ($i = 0; $i < 40; $i++) { $xor = ord($hmac[$i]) ^ ord($hmac_check[$i]); $diff |= $xor; } if ($diff !== 0) { log_message(‘error‘, ‘Session: HMAC mismatch. The session cookie data did not match what was expected.‘); $this->sess_destroy(); return FALSE; } // Decrypt the cookie data if ($this->sess_encrypt_cookie == TRUE) { $session = $this->CI->encrypt->decode($session); } // Unserialize the session array $session = $this->_unserialize($session); // Is the session data we unserialized an array with the correct format? if ( ! is_array($session) OR ! isset($session[‘session_id‘]) OR ! isset($session[‘ip_address‘]) OR ! isset($session[‘user_agent‘]) OR ! isset($session[‘last_activity‘])) { $this->sess_destroy(); return FALSE; } // Is the session current? if (($session[‘last_activity‘] + $this->sess_expiration) < $this->now) { $this->sess_destroy(); return FALSE; } // Does the IP Match? if ($this->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->sess_match_useragent == TRUE AND trim($session[‘user_agent‘]) != trim(substr($this->CI->input->user_agent(), 0, 120))) { $this->sess_destroy(); return FALSE; } // Is there a corresponding session in the DB? if ($this->sess_use_database === TRUE) { $this->CI->db->where(‘session_id‘, $session[‘session_id‘]); if ($this->sess_match_ip == TRUE) { $this->CI->db->where(‘ip_address‘, $session[‘ip_address‘]); } if ($this->sess_match_useragent == TRUE) { $this->CI->db->where(‘user_agent‘, $session[‘user_agent‘]); } $query = $this->CI->db->get($this->sess_table_name); // No result? Kill it! if ($query->num_rows() == 0) { $this->sess_destroy(); return FALSE; } // Is there custom data? If so, add it to the main session array $row = $query->row(); if (isset($row->user_data) AND $row->user_data != ‘‘) { $custom_data = $this->_unserialize($row->user_data); if (is_array($custom_data)) { foreach ($custom_data as $key => $val) { $session[$key] = $val; } } } } // Session is valid! $this->userdata = $session; unset($session); return TRUE; } // -------------------------------------------------------------------- /** * Write the session data * * @access public * @return void */ function sess_write() { // Are we saving custom data to the DB? If not, all we do is update the cookie if ($this->sess_use_database === FALSE) { $this->_set_cookie(); return; } // set the custom userdata, the session data we will set in a second $custom_userdata = $this->userdata; $cookie_userdata = array(); // Before continuing, we need to determine if there is any custom data to deal with. // Let‘s determine this by removing the default indexes to see if there‘s anything left in the array // and set the session data while we‘re at it foreach (array(‘session_id‘,‘ip_address‘,‘user_agent‘,‘last_activity‘) as $val) { unset($custom_userdata[$val]); $cookie_userdata[$val] = $this->userdata[$val]; } // Did we find any custom data? If not, we turn the empty array into a string // since there‘s no reason to serialize and store an empty array in the DB if (count($custom_userdata) === 0) { $custom_userdata = ‘‘; } else { // Serialize the custom data array so we can store it $custom_userdata = $this->_serialize($custom_userdata); } // Run the update query $this->CI->db->where(‘session_id‘, $this->userdata[‘session_id‘]); $this->CI->db->update($this->sess_table_name, array(‘last_activity‘ => $this->userdata[‘last_activity‘], ‘user_data‘ => $custom_userdata)); // Write the cookie. Notice that we manually pass the cookie data array to the // _set_cookie() function. Normally that function will store $this->userdata, but // in this case that array contains custom data, which we do not want in the cookie. $this->_set_cookie($cookie_userdata); } // -------------------------------------------------------------------- /** * Create a new session * * @access public * @return void */ function sess_create() { $sessid = ‘‘; while (strlen($sessid) < 32) { $sessid .= mt_rand(0, mt_getrandmax()); } // To make the session ID even more secure we‘ll combine it with the user‘s IP $sessid .= $this->CI->input->ip_address(); $this->userdata = array( ‘session_id‘ => md5(uniqid($sessid, TRUE)), ‘ip_address‘ => $this->CI->input->ip_address(), ‘user_agent‘ => substr($this->CI->input->user_agent(), 0, 120), ‘last_activity‘ => $this->now, ‘user_data‘ => ‘‘ ); // Save the data to the DB if needed if ($this->sess_use_database === TRUE) { $this->CI->db->query($this->CI->db->insert_string($this->sess_table_name, $this->userdata)); } // Write the cookie $this->_set_cookie(); } // -------------------------------------------------------------------- /** * Update an existing session * * @access public * @return void */ function sess_update() { // We only update the session every five minutes by default if ($this->CI->input->is_ajax_request() OR ($this->userdata[‘last_activity‘] + $this->sess_time_to_update) >= $this->now) { return; } // 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‘]; $new_sessid = ‘‘; while (strlen($new_sessid) < 32) { $new_sessid .= mt_rand(0, mt_getrandmax()); } // 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 $new_sessid = md5(uniqid($new_sessid, TRUE)); // Update the session data in the session data array $this->userdata[‘session_id‘] = $new_sessid; $this->userdata[‘last_activity‘] = $this->now; // _set_cookie() will handle this for us if we aren‘t using database sessions // by pushing all userdata to the cookie. $cookie_data = NULL; // Update the session ID and last_activity field in the DB if needed if ($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); } // -------------------------------------------------------------------- /** * Destroy the current session * * @access public * @return void */ function sess_destroy() { // Kill the session DB row if ($this->sess_use_database === TRUE && isset($this->userdata[‘session_id‘])) { $this->CI->db->where(‘session_id‘, $this->userdata[‘session_id‘]); $this->CI->db->delete($this->sess_table_name); } // Kill the cookie setcookie( $this->sess_cookie_name, addslashes(serialize(array())), ($this->now - 31500000), $this->cookie_path, $this->cookie_domain, 0 ); // Kill session data $this->userdata = array(); } // -------------------------------------------------------------------- /** * Fetch a specific item from the session array * * @access public * @param string * @return string */ function userdata($item) { return ( ! isset($this->userdata[$item])) ? FALSE : $this->userdata[$item]; } // -------------------------------------------------------------------- /** * Fetch all session data * * @access public * @return array */ function all_userdata() { return $this->userdata; } // -------------------------------------------------------------------- /** * Add or change data in the "userdata" array * * @access public * @param mixed * @param string * @return void */ function set_userdata($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]); } } $this->sess_write(); } // ------------------------------------------------------------------------ /** * Add or change flashdata, only available * until the next request * * @access public * @param mixed * @param string * @return void */ function set_flashdata($newdata = array(), $newval = ‘‘) { if (is_string($newdata)) { $newdata = array($newdata => $newval); } if (count($newdata) > 0) { foreach ($newdata as $key => $val) { $flashdata_key = $this->flashdata_key.‘:new:‘.$key; $this->set_userdata($flashdata_key, $val); } } } // ------------------------------------------------------------------------ /** * Keeps existing flashdata available to next request. * * @access public * @param string * @return void */ function keep_flashdata($key) { // ‘old‘ flashdata gets removed. Here we mark all // flashdata as ‘new‘ to preserve it from _flashdata_sweep() // Note the function will return FALSE if the $key // provided cannot be found $old_flashdata_key = $this->flashdata_key.‘:old:‘.$key; $value = $this->userdata($old_flashdata_key); $new_flashdata_key = $this->flashdata_key.‘:new:‘.$key; $this->set_userdata($new_flashdata_key, $value); } // ------------------------------------------------------------------------ /** * Fetch a specific flashdata item from the session array * * @access public * @param string * @return string */ function flashdata($key) { $flashdata_key = $this->flashdata_key.‘:old:‘.$key; return $this->userdata($flashdata_key); } // ------------------------------------------------------------------------ /** * Identifies flashdata as ‘old‘ for removal * when _flashdata_sweep() runs. * * @access private * @return void */ function _flashdata_mark() { $userdata = $this->all_userdata(); foreach ($userdata as $name => $value) { $parts = explode(‘:new:‘, $name); if (is_array($parts) && count($parts) === 2) { $new_name = $this->flashdata_key.‘:old:‘.$parts[1]; $this->set_userdata($new_name, $value); $this->unset_userdata($name); } } } // ------------------------------------------------------------------------ /** * Removes all flashdata marked as ‘old‘ * * @access private * @return void */ function _flashdata_sweep() { $userdata = $this->all_userdata(); foreach ($userdata as $key => $value) { if (strpos($key, ‘:old:‘)) { $this->unset_userdata($key); } } } // -------------------------------------------------------------------- /** * Get the "now" time * * @access private * @return string */ function _get_time() { if (strtolower($this->time_reference) == ‘gmt‘) { $now = time(); $time = mktime(gmdate("H", $now), gmdate("i", $now), gmdate("s", $now), gmdate("m", $now), gmdate("d", $now), gmdate("Y", $now)); } else { $time = time(); } return $time; } // -------------------------------------------------------------------- /** * Write the session cookie * * @access public * @return void */ function _set_cookie($cookie_data = NULL) { if (is_null($cookie_data)) { $cookie_data = $this->userdata; } // Serialize the userdata for the cookie $cookie_data = $this->_serialize($cookie_data); if ($this->sess_encrypt_cookie == TRUE) { $cookie_data = $this->CI->encrypt->encode($cookie_data); } $cookie_data .= hash_hmac(‘sha1‘, $cookie_data, $this->encryption_key); $expire = ($this->sess_expire_on_close === TRUE) ? 0 : $this->sess_expiration + time(); // Set the cookie setcookie( $this->sess_cookie_name, $cookie_data, $expire, $this->cookie_path, $this->cookie_domain, $this->cookie_secure ); } // -------------------------------------------------------------------- /** * Serialize an array * * This function first converts any slashes found in the array to a temporary * marker, so when it gets unserialized the slashes will be preserved * * @access private * @param array * @return string */ function _serialize($data) { if (is_array($data)) { foreach ($data as $key => $val) { if (is_string($val)) { $data[$key] = str_replace(‘\\‘, ‘{{slash}}‘, $val); } } } else { if (is_string($data)) { $data = str_replace(‘\\‘, ‘{{slash}}‘, $data); } } return serialize($data); } // -------------------------------------------------------------------- /** * Unserialize * * This function unserializes a data string, then converts any * temporary slash markers back to actual slashes * * @access private * @param array * @return string */ function _unserialize($data) { $data = @unserialize(strip_slashes($data)); if (is_array($data)) { foreach ($data as $key => $val) { if (is_string($val)) { $data[$key] = str_replace(‘{{slash}}‘, ‘\\‘, $val); } } return $data; } return (is_string($data)) ? str_replace(‘{{slash}}‘, ‘\\‘, $data) : $data; } // -------------------------------------------------------------------- /** * Garbage collection * * This deletes expired session rows from database * if the probability percentage is met * * @access public * @return void */ function _sess_gc() { if ($this->sess_use_database != TRUE) { return; } srand(time()); if ((rand() % 100) < $this->gc_probability) { $expire = $this->now - $this->sess_expiration; $this->CI->db->where("last_activity < {$expire}"); $this->CI->db->delete($this->sess_table_name); log_message(‘debug‘, ‘Session garbage collection performed.‘); } }}// END Session Class/* End of file Session.php *//* Location: ./system/libraries/Session.php */原文：http://www.cnblogs.com/wuyuxin/p/7039743.html