/**
?* CI是 session based cookie
?*/
class CI_Session {
?var $sess_encrypt_cookie??= FALSE;? //是否對session加密
?var $sess_use_database???= FALSE; //是否將session存入數據庫
?var $sess_table_name???= ''; //session存入數據的表名
?var $sess_expiration???= 7200; //session的過期時間
?var $sess_expire_on_close??= FALSE; //當瀏覽器窗口關閉時是否自動使session過期
?var $sess_match_ip????= FALSE;//是否通過用戶的IP地址來讀取 session 的數據
?var $sess_match_useragent??= TRUE; //是否要按照對應的 User Agent 來讀取 session 數據.
?var $sess_cookie_name???= 'ci_session'; //cookie名稱
?var $cookie_prefix????= ''; //cookie前綴
?var $cookie_path????= ''; //cookie路徑
?var $cookie_domain????= ''; //cookie作用域
?var $cookie_secure????= FALSE; //是否在安全的https協議下才有效
?var $sess_time_to_update??= 300; //session cookie多久更新一次
?var $encryption_key????= ''; //加密key
?var $flashdata_key????= 'flash';
?var $time_reference????= 'time';
?var $gc_probability????= 5;? //回收session的能力
?var $userdata?????= array(); //用戶session數據保存變量
?var $CI; //CI超級句柄
?var $now;? //當前時間
?public function __construct($params = array())
?{
??log_message('debug', "Session Class Initialized");
??// 獲取CI超級類
??$this->CI =& get_instance();
??// 獲取config文件中的配置數據
??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);
??}
??????????????? //必須設置encryption_key
??if ($this->encryption_key == '')
??{
???show_error('In order to use the Session class you are required to set an encryption key in your config file.');
??}
??// 加載string helper函數
??$this->CI->load->helper('string');
??// D如果對cookie進行加密,則引入加密類
??if ($this->sess_encrypt_cookie == TRUE)
??{
???$this->CI->load->library('encrypt');
??}
??// 如果session計入數據庫,則引入db
??if ($this->sess_use_database === TRUE AND $this->sess_table_name != '')
??{
???$this->CI->load->database();
??}
??// 獲取當前時間
??$this->now = $this->_get_time();
??// 如果沒有設置session的有效時間,默認兩年
??if ($this->sess_expiration == 0)
??{
???$this->sess_expiration = (60*60*24*365*2);
??}
??// 獲取cookie名稱
??$this->sess_cookie_name = $this->cookie_prefix.$this->sess_cookie_name;
??// 如果session不存在,創建新會話
??if ( ! $this->sess_read())
??{
???$this->sess_create();
??}
??else
??{
???$this->sess_update();
??}
??// 閃出標記old的閃出數據
??$this->_flashdata_sweep();
??????????????? //將新的閃出數據標記成old 標記成old的數據的數據將會在下次哀求時閃出
??$this->_flashdata_mark();
??//回收/刪除 過期的session
??$this->_sess_gc();
??log_message('debug', "Session routines successfully run");
?}
?// --------------------------------------------------------------------
?/**
? * 讀取session數據
? */
?function sess_read()
?{
??// 獲取session
??$session = $this->CI->input->cookie($this->sess_cookie_name);
??// 沒有session? 拜拜
??if ($session === FALSE)
??{
???log_message('debug', 'A session cookie was not found.');
???return FALSE;
??}
??// 如果加密了cookie
??if ($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;
???}
??}
??// 反序列化存入cookie的session數組
??$session = $this->_unserialize($session);
??// 檢測session的數據
??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;
??}
??// session數據過期了嗎
??if (($session['last_activity'] + $this->sess_expiration) < $this->now)
??{
???$this->sess_destroy();
???return FALSE;
??}
??// 是否是根據用戶ip來讀取session數據
??if ($this->sess_match_ip == TRUE AND $session['ip_address'] != $this->CI->input->ip_address())
??{
???$this->sess_destroy();
???return FALSE;
??}
??// 是否根據ua來匹配session數據
??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;
??}
??// 如果session入庫了,這種方式應該更安全點,當然負載大時,就不建議了,數據庫讀寫壓力大
??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;
?}
?// --------------------------------------------------------------------
?/**
? * 將讀取的session數據寫入
? */
?function sess_write()
?{
??// 是否寫入db
??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);
??}
??// 更新session記錄
??$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($cookie_userdata);
?}
?// --------------------------------------------------------------------
?/**
? * 創建一個新的session
? */
?function sess_create()
?{
??????????????? //保證sessid 安全唯一
??$sessid = '';
??while (strlen($sessid) < 32)
??{
???$sessid .= mt_rand(0, mt_getrandmax());
??}
??$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();
?}
?// --------------------------------------------------------------------
?/**
? * 更新session
? */
?function sess_update()
?{
??// 默認五分鐘更新
??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;
??// 更新數據庫中幾率
??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' => $old_sessid)));
??}
??// 重新寫入session
??$this->_set_cookie($cookie_data);
?}
?// --------------------------------------------------------------------
?/**
? *銷毀當前所有session數據
? */
?function sess_destroy()
?{
??// Kill the session DB row
??if ($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();
?}
?// --------------------------------------------------------------------
?/**
? * 獲取session數組指定元素的值
? */
?function userdata($item)
?{
??return ( ! isset($this->userdata[$item])) ? FALSE : $this->userdata[$item];
?}
?// --------------------------------------------------------------------
?/**
? * 獲取所有session數據
? */
?function all_userdata()
?{
??return $this->userdata;
?}
?// --------------------------------------------------------------------
?/**
? * 添加和修改自定義的session數據
? */
?function set_userdata($newdata = array(), $newval = '')
?{
??if (is_string($newdata))
??{
???$newdata = array($newdata => $newval);
??}
??????????????? //支持數組組合方式
??if (count($newdata) > 0)
??{
???foreach ($newdata as $key => $val)
???{
????$this->userdata[$key] = $val;
???}
??}
??$this->sess_write();
?}
?// --------------------------------------------------------------------
?/**
? * 刪除session數組中的元素,
? */
?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, $val);
???}
??}
?}
?// ------------------------------------------------------------------------
?/**
? * CI支持閃出數據也就是說 Session數據只對下次服務器哀求可用,有時候如果你還想在下個哀求后的哀求還有效...
???????? * keep_flashdata功能就是講持續保持閃出數據,使其在下個哀求也有效
? */
?function keep_flashdata($key)
?{
??????????????? //將閃出數據標記成new
??$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, $value);
?}
?// ------------------------------------------------------------------------
?/**
? * 獲取閃出數據
? */
?function flashdata($key)
?{
??$flashdata_key = $this->flashdata_key.':old:'.$key;
??return $this->userdata($flashdata_key);
?}
?// ------------------------------------------------------------------------
?/**
? * 將閃出數據標記成old,以便_flashdata_sweep清除數據
? */
?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($name);
???}
??}
?}
?// ------------------------------------------------------------------------
?/**
? * 將標記成old的閃出數據閃出
? */
?function _flashdata_sweep()
?{
??$userdata = $this->all_userdata();
??foreach ($userdata as $key => $value)
??{
???if (strpos($key, ':old:'))
???{
????$this->unset_userdata($key);
???}
??}
?}
?//獲取當前時間
?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 $time;
?}
?// --------------------------------------------------------------------
?/**
? * 寫入session cookie
? *
? */
?function _set_cookie($cookie_data = NULL)
?{
??if (is_null($cookie_data))
??{
???$cookie_data = $this->userdata;
??}
??// 序列化數組
??$cookie_data = $this->_serialize($cookie_data);
??????????????? //加密數據
??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.$this->encryption_key);
??}
??????????????? //sess_expire_on_close為TRUE則,瀏覽器關閉,session失效
??$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,
?????$this->cookie_secure
????);
?}
?// --------------------------------------------------------------------
?/**
? * 序列化數組
? */
?function _serialize($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);
?}
?// --------------------------------------------------------------------
?/**
? * 反序列化數組
? */
?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) : $data;
?}
?// --------------------------------------------------------------------
?/**
? * 回收/刪除數據庫中失效的session信息
? */
?function _sess_gc()
?{
??if ($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.');
??}
?}
}