CI的Session并不是原生的session，正是我前面所有的cookie based session,另外，CI可以根据用户选择配置是否将session存入数据库中，本人很喜欢这个功能，还有就是“闪出数据”的功能，既闪出数据只是对下次服务器请求可以，之后就会被自动清除。常见使用方法有：
$this->session->set_userdata("some_name", "some_value"); //设置session数据
$this->session->userdata("item"); //获取session数据
$this->session->unset_userdata("some_name"); //删除session数据
$this->session->sess_destroy(); //销毁session数据
$this->session->set_flashdata("item", "value"); //设置闪存数据
$this->session->flashdata("item"); //获取闪存数据
$this->session->keep_flashdata("item"); //保留闪存数据
复制代码 代码如下:
/**
* 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);
}
// --------------------------------------------------------------------
/**
* 创建一个新的session
*/
function sess_create()
{
//保证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
$this->_set_cookie();
}
// --------------------------------------------------------------------
/**
* 更新session
*/
function sess_update()
{
// 默认五分钟更新
if (($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.");
}
}
}
