CI Framework Session. php Source Code Analysis
- 2021-07-24 10:21:10
- OfStack
Session of CI is not the native session, it is all cookie based session in front of me. In addition, CI can configure whether session is stored in the database according to the user's choice. I like this function very much, and there is the function of "flash data", which can only flash data for the next server request, and then it will be automatically cleared. Common usage methods are:
$this- > session- > set_userdata ('some_name', 'some_value'); //Set session data
$this- > session- > userdata ('item'); //Get session data
$this- > session- > unset_userdata ('some_name'); //Delete session data
$this- > session- > sess_destroy (); //Destroy session data
$this- > session- > set_flashdata ('item', 'value'); //Set up flash data
$this- > session- > flashdata ('item'); //Get flash data
$this- > session- > keep_flashdata ('item'); //Retain flash data
/**
* CI是 session based cookie
*/
class CI_Session {
var $sess_encrypt_cookie = FALSE; //是否对session加密
var $sess_use_database = FALSE; //是否将session存入数据库
var $sess_table_name = ''; //session存入数据的表名
var $sess_expiration = 7200; //session的过期时间
var $sess_expire_on_close = FALSE; //当浏览器窗口关闭时是否自动使session过期
var $sess_match_ip = FALSE;//是否通过用户的IP地址来读取 session 的数据
var $sess_match_useragent = TRUE; //是否要按照对应的 User Agent 来读取 session 数据。
var $sess_cookie_name = 'ci_session'; //cookie名称
var $cookie_prefix = ''; //cookie前缀
var $cookie_path = ''; //cookie路径
var $cookie_domain = ''; //cookie作用域
var $cookie_secure = FALSE; //是否在安全的https协议下才有效
var $sess_time_to_update = 300; //session cookie多久更新1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(); //用户session数据保存变量
var $CI; //CI超级句柄
var $now; //当前时间
public function __construct($params = array())
{
log_message('debug', "Session Class Initialized");
// 获取CI超级类
$this->CI =& get_instance();
// 获取config文件中的配置数据
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);
}
//必须设置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.');
}
// 加载string helper函数
$this->CI->load->helper('string');
// D如果对cookie进行加密，则引入加密类
if ($this->sess_encrypt_cookie == TRUE)
{
$this->CI->load->library('encrypt');
}
// 如果session计入数据库，则引入db
if ($this->sess_use_database === TRUE AND $this->sess_table_name != '')
{
$this->CI->load->database();
}
// 获取当前时间
$this->now = $this->_get_time();
// 如果没有设置session的有效时间，默认两年
if ($this->sess_expiration == 0)
{
$this->sess_expiration = (60*60*24*365*2);
}
// 获取cookie名称
$this->sess_cookie_name = $this->cookie_prefix.$this->sess_cookie_name;
// 如果session不存在，创建新会话
if ( ! $this->sess_read())
{
$this->sess_create();
}
else
{
$this->sess_update();
}
// 闪出标记old的闪出数据
$this->_flashdata_sweep();
//将新的闪出数据标记成old 标记成old的数据的数据将会在下次请求时闪出
$this->_flashdata_mark();
//回收/删除 过期的session
$this->_sess_gc();
log_message('debug', "Session routines successfully run");
}
// --------------------------------------------------------------------
/**
* 读取session数据
*/
function sess_read()
{
// 获取session
$session = $this->CI->input->cookie($this->sess_cookie_name);
// 没有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数组
$session = $this->_unserialize($session);
// 检测session的数据
if ( ! is_array($session) OR ! isset($session['session_id']) OR ! isset($session['ip_address']) OR ! isset($session['user_agent']) OR ! isset($session['last_activity']))
{
$this->sess_destroy();
return FALSE;
}
// session数据过期了吗
if (($session['last_activity'] + $this->sess_expiration) < $this->now)
{
$this->sess_destroy();
return FALSE;
}
// 是否是根据用户ip来读取session数据
if ($this->sess_match_ip == TRUE AND $session['ip_address'] != $this->CI->input->ip_address())
{
$this->sess_destroy();
return FALSE;
}
// 是否根据ua来匹配session数据
if ($this->sess_match_useragent == TRUE AND trim($session['user_agent']) != trim(substr($this->CI->input->user_agent(), 0, 120)))
{
$this->sess_destroy();
return FALSE;
}
// 如果session入库了，这种方式应该更安全点，当然负载大时，就不建议了，数据库读写压力大
if ($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;
}
// --------------------------------------------------------------------
/**
* 将读取的session数据写入
*/
function sess_write()
{
// 是否写入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记录
$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);
}
// --------------------------------------------------------------------
/**
* 创建1个新的session
*/
function sess_create()
{
//保证sessid 安全唯1
$sessid = '';
while (strlen($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
$this->_set_cookie();
}
// --------------------------------------------------------------------
/**
* 更新session
*/
function sess_update()
{
// 默认5分钟更新
if (($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.
$cookie_data = NULL;
// 更新数据库中几率
if ($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)));
}
// 重新写入session
$this->_set_cookie($cookie_data);
}
// --------------------------------------------------------------------
/**
*销毁当前所有session数据
*/
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
$this->userdata = array();
}
// --------------------------------------------------------------------
/**
* 获取session数组指定元素的值
*/
function userdata($item)
{
return ( ! isset($this->userdata[$item])) ? FALSE : $this->userdata[$item];
}
// --------------------------------------------------------------------
/**
* 获取所有session数据
*/
function all_userdata()
{
return $this->userdata;
}
// --------------------------------------------------------------------
/**
* 添加和修改自定义的session数据
*/
function set_userdata($newdata = array(), $newval = '')
{
if (is_string($newdata))
{
$newdata = array($newdata => $newval);
}
//支持数组组合方式
if (count($newdata) > 0)
{
foreach ($newdata as $key => $val)
{
$this->userdata[$key] = $val;
}
}
$this->sess_write();
}
// --------------------------------------------------------------------
/**
* 删除session数组中的元素，
*/
function unset_userdata($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, $val);
}
}
}
// ------------------------------------------------------------------------
/**
* CI支持闪出数据也就是说 Session数据只对下次服务器请求可用,有时候如果你还想在下个请求后的请求还有效。。。
* keep_flashdata功能就是讲持续保持闪出数据，使其在下个请求也有效
*/
function keep_flashdata($key)
{
//将闪出数据标记成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, $value);
}
// ------------------------------------------------------------------------
/**
* 获取闪出数据
*/
function flashdata($key)
{
$flashdata_key = $this->flashdata_key.':old:'.$key;
return $this->userdata($flashdata_key);
}
// ------------------------------------------------------------------------
/**
* 将闪出数据标记成old，以便_flashdata_sweep清除数据
*/
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);
}
}
}
// ------------------------------------------------------------------------
/**
* 将标记成old的闪出数据闪出
*/
function _flashdata_sweep()
{
$userdata = $this->all_userdata();
foreach ($userdata as $key => $value)
{
if (strpos($key, ':old:'))
{
$this->unset_userdata($key);
}
}
}
//获取当前时间
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 $time;
}
// --------------------------------------------------------------------
/**
* 写入session cookie
*
*/
function _set_cookie($cookie_data = NULL)
{
if (is_null($cookie_data))
{
$cookie_data = $this->userdata;
}
// 序列化数组
$cookie_data = $this->_serialize($cookie_data);
//加密数据
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为TRUE则，浏览器关闭，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,
$this->cookie_secure
);
}
// --------------------------------------------------------------------
/**
* 序列化数组
*/
function _serialize($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);
}
// --------------------------------------------------------------------
/**
* 反序列化数组
*/
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) : $data;
}
// --------------------------------------------------------------------
/**
* 回收/删除数据库中失效的session信息
*/
function _sess_gc()
{
if ($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.');
}
}
}