直接上代码：

代码如下:

class dbsession

{

const type_int = 1;

const type_str = 2;

/**

* database configration

*

* @var array

*/

private $_config = array(

‘host' => '127.0.0.1′,

‘port' => 3306,

‘username' => ‘root',

‘password' => ‘root',

‘dbname' => ‘db_mylab',

‘tablename' => ‘t_sessions',

‘cookie_prefix' => ‘mylab_',

‘cookiepath' => ‘/',

‘cookiedomain' => ”,

‘cookie_timeout' => 900

);

/**

* table fields type array

*

* @var array

*/

private $_db_fields = array(

‘crc32sid' => self::type_int,

‘sessionhash' => self::type_str,

‘idhash' => self::type_str,

‘userid' => self::type_int,

‘ipaddress' => self::type_str,

‘lastactivity' => self::type_str,

‘location' => self::type_str,

‘loggedin' => self::type_int,

‘heartbeat' => self::type_str

);

/**

* db obj

*

* @var mysqli object

*/

private $_mysqli = null;

/**

* weather the session was created or existed previously

*

* @var bool

*/

private $_created = false;

/**

* array of changes.

*

* @var array

*/

private $_changes = array();

/**

* @var bool

*/

private $_db_inited = false;

/**

* session host

*

* @var string

*/

private $_session_host = ”;

/**

* session idhash

*

* @var string

*/

private $_session_idhash = ”;

private $_dbsessionhash = ”;

private $_vars = array();

public function __construct()

{

$this->_dbsessionhash = addslashes($this->get_cookie(‘sessionhash'));

$this->_session_host = substr($_server[‘remote_addr'], 0, 15);

#this should *never* change during a session

$this->_session_idhash = md5($_server[‘http_user_agent'] . self::fetch_substr_ip(self::fetch_alt_ip()) );

$this->_init_config();

$this->init_db();

$gotsession = false;

if ($this->_dbsessionhash)

{

$sql = ‘

select *

from ‘ . $this->_config[‘tablename'] . ‘

where crc32sid = ‘ . sprintf(‘%u', crc32($this->_dbsessionhash)) . ‘

and sessionhash = '‘ . $this->_dbsessionhash . ‘'

and idhash = '‘ . $this->_session_idhash . ‘'

and heartbeat > '‘ . date(‘y-m-d h:i:s' ,timenow – $this->_config[‘cookie_timeout']) . ‘'‘;

//echo $sql;exit;

$result = $this->_mysqli->query($sql);

$session = $result->fetch_array(mysqli_assoc);

if ($session and ($this->fetch_substr_ip($session[‘ipaddress']) == $this->fetch_substr_ip($this->_session_host)))

{

$gotsession = true;

$this->_vars = $session;

$this->_created = false;

}

}

if ($gotsession == false)

{

$this->_vars = $this->fetch_session();

$this->_created = true;

$gotsession = true;

}

if ($this->_created == false)

{

$this->set(‘lastactivity', date(‘y-m-d h:i:s', timenow));

$this->set(‘location', $_server[‘request_uri']);

}

}

/**

* builds an array that can be used to build a query to insert/update the session

*

* @return array array of column name => prepared value

*/

private function _build_query_array()

{

$return = array();

foreach ($this->_db_fields as $fieldname => $cleantype)

{

switch ($cleantype)

{

case self::type_int:

$cleaned = is_numeric($this->_vars[$fieldname]) ? $this->_vars[$fieldname] : intval($this->_vars[$fieldname]);

break;

case self::type_str:

default:

$cleaned = ' . addslashes($this->_vars[$fieldname]) . ';

}

$return[$fieldname] = $cleaned;

}

return $return;

}

/**

* sets a session variable and updates the change list.

*

* @param string name of session variable to update

* @param string value to update it with

*/

public function set($key, $value)

{

if ($this->_vars[$key] != $value)

{

$this->_vars[$key] = $value;

$this->_changes[$key] = true;

}

}

public function get($key)

{

return $this->_vars[$key];

}

public function unsetchangedvar($var)

{

if (isset($this->_changes[$var]))

{

unset($this->_changes[$var]);

}

}

/**

* fetches a valid sessionhash value, not necessarily the one tied to this session.

*

* @return string 32-character sessionhash

*/

static function fetch_sessionhash()

{

return hash(‘md5′ , timenow . rand(1, 100000) . uniqid() );

}

private function _init_config()

{

$registry = zend_registry::getinstance();

$config = $registry->get(‘config');

$this->_config[‘host'] = $config->database->params->host;

$this->_config[‘port'] = $config->database->params->port;

$this->_config[‘username'] = $config->database->params->username;

$this->_config[‘password'] = $config->database->params->password;

$this->_config[‘dbname'] = $config->database->params->dbname;

$this->_config[‘tablename'] = $config->database->session->tablename;

}

/**

* initialize database connection

*/

public function init_db()

{

if ($this->_db_inited)

{

return true;

}

//mysqli_report(mysqli_report_off);

$this->_mysqli = new mysqli(

$this->_config[‘host'],

$this->_config[‘username'],

$this->_config[‘password'],

$this->_config[‘dbname'],

$this->_config[‘port']

);

/* check connection */

if (mysqli_connect_errno())

{

// printf(connect failed: %sn, mysqli_connect_error());

// echo ‘in ‘, __file__, ‘ on line ‘, __line__;

echo { success: false, errors: { reason: ‘ connect failed: . addslashes( mysqli_connect_error() ) . ' }};

exit();

}

$this->_mysqli->query(‘set names latin1′);

$this->_db_inited = true;

return true;

}

/**

* fetches an alternate ip address of the current visitor, attempting to detect proxies etc.

*

* @return string

*/

static function fetch_alt_ip()

{

$alt_ip = $_server[‘remote_addr'];

if (isset($_server[‘http_client_ip']))

{

$alt_ip = $_server[‘http_client_ip'];

}

else if (isset($_server[‘http_from']))

{

$alt_ip = $_server[‘http_from'];

}

return $alt_ip;

}

/**

* returns the ip address with the specified number of octets removed

*

* @param string ip address

*

* @return string truncated ip address

*/

static function fetch_substr_ip($ip, $length = null)

{

return implode(‘.', array_slice(explode(‘.', $ip), 0, 4 – $length));

}

/**

* fetches a default session. used when creating a new session.

*

* @param integer user id the session should be for

*

* @return array array of session variables

*/

public function fetch_session($userid = 0)

{

$sessionhash = self::fetch_sessionhash();

$this->set_cookie(‘sessionhash', $sessionhash);

return array(

‘crc32sid' => sprintf(‘%u', crc32($sessionhash)),

‘sessionhash' => $sessionhash,

‘idhash' => $this->_session_idhash,

‘userid' => $userid,

‘ipaddress' => $this->_session_host,

‘lastactivity' => date(‘y-m-d h:i:s', timenow),

‘location' => $_server[‘request_uri'],

‘loggedin' => $userid ? 1 : 0,

‘heartbeat' => date(‘y-m-d h:i:s', timenow)

);

}

public function get_cookie($cookiename)

{

$full_cookiename = $this->_config[‘cookie_prefix'] . $cookiename;

if (isset($_cookie[$full_cookiename]))

{

return $_cookie[$full_cookiename];

}

else

{

return false;

}

}

public function set_cookie($name, $value = ”, $permanent = 1, $allowsecure = true)

{

if ($permanent)

{

$expire = timenow + 60 * 60 * 24 * 365;

}

else

{

$expire = 0;

}

if ($_server[‘server_port'] == '443′)

{

// we're using ssl

$secure = 1;

}

else

{

$secure = 0;

}

// check for ssl

$secure = ((req_protocol === ‘https' and $allowsecure) ? true : false);

$name = $this->_config[‘cookie_prefix'] . $name;

$filename = ‘n/a';

$linenum = 0;

if (!headers_sent($filename, $linenum))

{ // consider showing an error message if there not sent using above variables?

if ($value == ” and strlen($this->_config[‘cookiepath']) > 1 and strpos($this->_config[‘cookiepath'], ‘/') !== false)

{

// this will attempt to unset the cookie at each directory up the path.

// ie, cookiepath = /test/abc/. these will be unset: /, /test, /test/, /test/abc, /test/abc/

// this should hopefully prevent cookie conflicts when the cookie path is changed.

$dirarray = explode(‘/', preg_replace(‘#/+$#', ”, $this->_config[‘cookiepath']));

$alldirs = ”;

foreach ($dirarray as $thisdir)

{

$alldirs .= $thisdir;

if (!empty($thisdir))

{ // try unsetting without the / at the end

setcookie($name, $value, $expire, $alldirs, $this->_config[‘cookiedomain'], $secure);

}

$alldirs .= /;

setcookie($name, $value, $expire, $alldirs, $this->_config[‘cookiedomain'], $secure);

}

}

else

{

setcookie($name, $value, $expire, $this->_config[‘cookiepath'], $this->_config[‘cookiedomain'], $secure);

}

}

else if (!debug)

{

echo can't set cookies;

}

}

private function _save()

{

$cleaned = $this->_build_query_array();

if ($this->_created)

{

//var_dump($cleaned);

# insert query

$this->_mysqli->query(‘

insert ignore into ‘ . $this->_config[‘tablename'] . ‘

(‘ . implode(‘,', array_keys($cleaned)) . ‘)

values

(‘ . implode(‘,', $cleaned). ‘)

‘);

}

else

{

# update query

$update = array();

foreach ($cleaned as $key => $value)

{

if (!empty($this->_changes[$key]))

{

$update[] = $key = $value;

}

}

if (sizeof($update) > 0)

{

$sql = ‘update ‘ . $this->_config[‘tablename'] . ‘

set ‘ . implode(‘, ‘, $update) . ‘

where crc32sid = ‘ . sprintf(‘%u', crc32($this->_dbsessionhash)) . ‘

and sessionhash = '‘ . $this->_dbsessionhash . ‘'‘;

//echo $sql;

$this->_mysqli->query($sql);

}

}

}

public function getonlineusernum()

{

$sql = ‘

select count(*) as cnt

from ‘ . $this->_config[‘tablename'] . ‘

where loggedin = 1

and heartbeat > '‘ . date(‘y-m-d h:i:s' ,timenow – $this->_config[‘cookie_timeout']) . ‘'‘;

$result = $this->_mysqli->query($sql);

$row = $result->fetch_array(mysqli_assoc);

return $row[‘cnt'];

}

private function _gc()

{

$rand_num = rand(); # randow integer between 0 and getrandmax()

if ($rand_num < 100)

{

$sql = ‘delete from ‘ . $this->_config[‘tablename'] . ‘

where heartbeat < '‘ . date(‘y-m-d h:i:s' ,timenow – $this->_config[‘cookie_timeout']) . ‘'‘;

$this->_mysqli->query($sql);

}

}

public function __destruct()

{

$this->_save();

$this->_gc();

$this->_mysqli->close();

}

}

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