CI session 类的用法

最近使用codeingiter框架，发现默认的session 不是很好用，以下是用法总结：使用的是2.0.2的版本

1.扩展自带的session类：application/libraries/MY_session.php 新增的扩展文件

<?php  if (!defined('BASEPATH')) exit('No direct script access allowed');
/**
* Session class using native PHP session.
*
* @package     CodeIgniter
* @subpackage  Libraries
* @category    Sessions
* @author      Yvo van Dillen
* @link        http://www.atomicon.nl
*/

/*
Example config file: session.php

<?php

//The session name (leave empty for cross application sessions)
$config['sess_name']       = '';

//Time to expire a session AND/OR regenerate the session id
$config['sess_expiration'] = 7200;

//If you want to change the session id every 'sess_expiration' seconds
//turn this to true
$config['sess_regenerate'] = FALSE;

//The flashdata key (this only applies to flashmessages)
$config['sess_flash_key']  = 'flash';


*/


class MY_Session
{
    function __construct()
    {
        log_message('debug', "MY_Session Class Initialized");
        get_instance()->load->config('session', FALSE, TRUE);
        $this->_sess_run();
    }

    function data()
    {
        return $_SESSION;
    }

    /**
    * Regenerates session id
    */
    function regenerate_id()
    {
        // copy old session data, including its id
        $old_session_id = session_id();
        $old_session_data = isset($_SESSION) ? $_SESSION : array();

        // regenerate session id and store it
        session_regenerate_id();
        $new_session_id = session_id();

        // switch to the old session and destroy its storage
        if (session_id($old_session_id))
        {
            session_destroy();
        }

        // switch back to the new session id and send the cookie

        if ($new_session_id)
        {
            session_id($new_session_id);
            session_start();

            // restore the old session data into the new session
            $_SESSION = $old_session_data;
        }

        // end the current session and store session data.
        session_write_close();
    }

    /**
    * Destroys the session and erases session storage
    */
    function destroy()
    {
        $_SESSION = array();
        if ( isset( $_COOKIE[session_name()] ) )
        {
            setcookie(session_name(), '', time()-42000, '/');
        }
        session_destroy();
    }

    function sess_create()
    {
        $this->_sess_run();
    }

    function sess_destroy()
    {
        $this->destroy();
    }

    /**
    * Reads given session attribute value
    */
    function userdata($item)
    {
        if($item == 'session_id'){ //added for backward-compatibility
            return session_id();
        }else{
            return ( ! isset($_SESSION[$item])) ? false : $_SESSION[$item];
        }
    }

    public function all_userdata()
    {
        return (array)$_SESSION;
    }

    /**
    * Sets session attributes to the given values
    */
    function set_userdata($newdata = array(), $newval = '')
    {
        if (is_string($newdata))
        {
            $newdata = array($newdata => $newval);
        }

        if (count($newdata) > 0)
        {
            foreach ($newdata as $key => $val)
            {
                $_SESSION[$key] = $val;
            }
        }
    }

    /**
    * Erases given session attributes
    */
    function unset_userdata($newdata = array())
    {
        if (is_string($newdata))
        {
            $newdata = array($newdata => '');
        }

        if (count($newdata) > 0)
        {
            foreach ($newdata as $key => $val)
            {
                unset($_SESSION[$key]);
            }
        }
    }

    /**
    * Starts up the session system for current request
    */
    function _sess_run()
    {
        if (config_item('sess_name'))
        {
            session_name(config_item('sess_name'));
        }

        if (session_id()=='')
        {
            session_start();
        }

        // check if session id needs regeneration
        if ( $this->_session_id_expired() )
        {
            // regenerate session id (session data stays the
            // same, but old session storage is destroyed)
            if (config_item('sess_regenerate'))
            {
                $this->regenerate_id();
                return;
            }
        }

        // 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();
    }

    /**
    * Checks if session has expired
    */
    function _session_id_expired()
    {
        $sess_expiration = config_item('sess_expiration');
        if (is_numeric($sess_expiration) && $sess_expiration > 0)
        {
            if (config_item('sess_regenerate'))
            {
                if ( !isset($_SESSION['_sess:last-generated']) )
                {
                    $_SESSION['_sess:last-generated'] = time();
                    return false;
                }
                else
                {
                    $expiry_time = $_SESSION['_sess:last-generated'] + $sess_expiration;
                    if (time() >= $expiry_time)
                    {
                        return true;
                    }
                }
            }
            else
            {
                if (isset($_SESSION['_sess:last-activation']))
                {
                    $expiry_time = $_SESSION['_sess:last-activation'] + $sess_expiration;
                    if (time() >= $expiry_time)
                    {
                        $this->destroy();
                        return true;
                    }
                }
                $_SESSION['_sess:last-activation'] = time();
            }
        }
        return false;
    }

    /**
    * Sets "flash" data which will be available only in next request (then it will
    * be deleted from session). You can use it to implement "Save succeeded" messages
    * after redirect.
    */
    function set_flashdata($key, $value)
    {
        $flash_key = config_item('sess_flash_key').':new:'.$key;
        $this->set_userdata($flash_key, $value);
    }

    /**
    * Keeps existing "flash" data available to next request.
    */
    function keep_flashdata($key)
    {
        $old_flash_key = config_item('sess_flash_key').':old:'.$key;
        $value = $this->userdata($old_flash_key);

        $new_flash_key = config_item('sess_flash_key').':new:'.$key;
        $this->set_userdata($new_flash_key, $value);
    }

    /**
    * Returns "flash" data for the given key.
    */
    function flashdata($key)
    {
        $flash_key = config_item('sess_flash_key').':old:'.$key;
        return $this->userdata($flash_key);
    }

    /**
    * PRIVATE: Internal method - marks "flash" session attributes as 'old'
    */
    function _flashdata_mark()
    {
        foreach ($_SESSION as $name => $value)
        {
            $parts = explode(':new:', $name);
            if (is_array($parts) && count($parts) == 2)
            {
                $new_name = config_item('sess_flash_key').':old:'.$parts[1];
                $this->set_userdata($new_name, $value);
                $this->unset_userdata($name);
            }
        }
    }

    /**
    * PRIVATE: Internal method - removes "flash" session marked as 'old'
    */
    function _flashdata_sweep()
    {
        foreach ($_SESSION as $name => $value)
        {
            $parts = explode(':old:', $name);
            if (is_array($parts) && count($parts) == 2 && $parts[0] == config_item('sess_flash_key'))
            {
                $this->unset_userdata($name);
            }
        }
    }
}

2.在控制器中使用方法：

设置session:注意 如果把 数组赋给一个变量，则不起效果

$this->session->set_userdata(array(
                'authorization' => array(
                    'id'   => 111,
                    'code' => '222',
                )
            ));

3.获取session:

print_r( $this->session->userdata('authorization') ) ;