Here's the code, an explanation will follow:
<?php
class Session
{
/**
* Path to save the sessions to
* @var string
*/
private $savePathRoot = '/tmp';
/**
* Save path of the saved path
* @var string
*/
private $savePath = '';
/**
* Salt for hashing the session data
* @var string
*/
private $key = '282edfcf5073666f3a7ceaa5e748cf8128bd53359b6d8269ba2450404face0ac';
/**
* Init the object, set up the session config handling
*
* @return null
*/
public function __construct()
{
session_set_save_handler(
array($this, "open"), array($this, "close"), array($this, "read"),
array($this, "write"),array($this, "destroy"),array($this, "gc")
);
$this->savePathRoot = ini_get('session.save_path');
}
/**
* Encrypt the given data
*
* @param mixed $data Session data to encrypt
* @return mixed $data Encrypted data
*/
private function encrypt($data)
{
$ivSize = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_CBC);
$iv = mcrypt_create_iv($ivSize, MCRYPT_RAND);
$keySize = mcrypt_get_key_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_CBC);
$key = substr(sha1($this->key), 0, $keySize);
// add in our IV and base64 encode the data
$data = base64_encode(
$iv.mcrypt_encrypt(
MCRYPT_RIJNDAEL_256, $key, $data, MCRYPT_MODE_CBC, $iv
)
);
return $data;
}
/**
* Decrypt the given session data
*
* @param mixed $data Data to decrypt
* @return $data Decrypted data
*/
private function decrypt($data)
{
$data = base64_decode($data, true);
$ivSize = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_CBC);
$keySize = mcrypt_get_key_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_CBC);
$key = substr(sha1($this->key), 0, $keySize);
$iv = substr($data, 0, $ivSize);
$data = substr($data, $ivSize);
$data = mcrypt_decrypt(
MCRYPT_RIJNDAEL_256, $key, $data, MCRYPT_MODE_CBC, $iv
);
return $data;
}
/**
* Set the key for the session encryption to use (default is set)
*
* @param string $key Key string
* @return null
*/
public function setKey($key)
{
$this->key = $key;
}
/**
* Write to the session
*
* @param integer $id Session ID
* @param mixed $data Data to write to the log
* @return null
*/
public function write($id, $data)
{
$path = $this->savePathRoot.'/'.$id;
$data = $this->encrypt($data);
file_put_contents($path, $data);
}
/**
* Read in the session
*
* @param string $id Session ID
* @return null
*/
public function read($id)
{
$path = $this->savePathRoot.'/'.$id;
$data = null;
if (is_file($path)) {
// get the data and extract the IV
$data = file_get_contents($path);
$data = $this->decrypt($data);
}
return $data;
}
/**
* Open the session
*
* @param string $savePath Path to save the session file locally
* @param string $sessionId Session ID
* @return null
*/
public function open($savePath, $sessionId)
{
// open session, do nothing by default
}
/**
* Close the session
*
* @return boolean Default return (true)
*/
public function close()
{
return true;
}
/**
* Perform garbage collection on the session
*
* @param int $maxlifetime Lifetime in seconds
* @return null
*/
public function gc($maxlifetime)
{
$path = $this->savePathRoot.'/*';
foreach (glob($path) as $file) {
if (filemtime($file) + $maxlifetime < time() && file_exists($file)) {
unlink($file);
}
}
return true;
}
/**
* Destroy the session
*
* @param string $id Session ID
* @return null
*/
public function destroy($id)
{
$path = $this->savePathRoot.'/'.$id;
if (is_file($path)) {
unlink($path);
}
return true;
}
}
?>
Resources
