CodeIgniter installed
[living-lab-site.git] / system / libraries / Session.php
diff --git a/system/libraries/Session.php b/system/libraries/Session.php
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+<?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             ExpressionEngine Dev Team
+ * @copyright  Copyright (c) 2008 - 2011, EllisLab, Inc.
+ * @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             ExpressionEngine 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 ($session === FALSE)
+               {
+                       log_message('debug', 'A session cookie was not found.');
+                       return FALSE;
+               }
+
+               // Decrypt the cookie data
+               if ($this->sess_encrypt_cookie == TRUE)
+               {
+                       $session = $this->CI->encrypt->decode($session);
+               }
+               else
+               {
+                       // encryption was not used, so we need to check the md5 hash
+                       $hash    = substr($session, strlen($session)-32); // get last 32 chars
+                       $session = substr($session, 0, strlen($session)-32);
+
+                       // Does the md5 hash match?  This is to prevent manipulation of session data in userspace
+                       if ($hash !==  md5($session.$this->encryption_key))
+                       {
+                               log_message('error', 'The session cookie data did not match what was expected. This could be a possible hacking attempt.');
+                               $this->sess_destroy();
+                               return FALSE;
+                       }
+               }
+
+               // 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, 50)))
+               {
+                       $this->sess_destroy();
+                       return FALSE;
+               }
+
+               // Is there a corresponding session in the DB?
+               if ($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, 50),
+                                                       'last_activity' => $this->now
+                                                       );
+
+
+               // Save the data to the DB if needed
+               if ($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->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 ($this->sess_use_database === TRUE AND isset($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,
+                                       $this->cookie_domain,
+                                       0
+                               );
+       }
+
+       // --------------------------------------------------------------------
+
+       /**
+        * Fetch a specific item from the session array
+        *
+        * @access      public
+        * @param       string
+        * @return      string
+        */
+       function userdata($item)
+       {
+               return ( ! isset($this->userdata[$item])) ? FALSE : $this->userdata[$item];
+       }
+
+       // --------------------------------------------------------------------
+
+       /**
+        * Fetch all session data
+        *
+        * @access      public
+        * @return      mixed
+        */
+       function all_userdata()
+       {
+               return ( ! isset($this->userdata)) ? FALSE : $this->userdata;
+       }
+
+       // --------------------------------------------------------------------
+
+       /**
+        * Add or change data in the "userdata" array
+        *
+        * @access      public
+        * @param       mixed
+        * @param       string
+        * @return      void
+        */
+       function set_userdata($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);
+               }
+               else
+               {
+                       // if encryption is not used, we provide an md5 hash to prevent userside tampering
+                       $cookie_data = $cookie_data.md5($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 */
\ No newline at end of file