I noticed that the posted solutions for manually decoding sessions are not perfect, so I've contributed a more robust solution.
The preg_match solution can never work. It's not so hard to find a case that might break unserialization.
In the case of jason-joeymail is breaks on:
<?php
$_SESSION["test"] = ";oops|";
?>
Below you can find my solution. It doesn't use a regular expression but rather the reversibility of the serialize operation and the 'feature' that serialize ignores all further input when it thinks it's done. It's by no means a beautiful or particularly fast solution but it is a more robust solution.
I've added a deserializer for "php" and "php_binary". It should be trivial to add one for "wddx".
<?php
class Session {
public static function unserialize($session_data) {
$method = ini_get("session.serialize_handler");
switch ($method) {
case "php":
return self::unserialize_php($session_data);
break;
case "php_binary":
return self::unserialize_phpbinary($session_data);
break;
default:
throw new Exception("Unsupported session.serialize_handler: " . $method . ". Supported: php, php_binary");
}
}
private static function unserialize_php($session_data) {
$return_data = array();
$offset = 0;
while ($offset < strlen($session_data)) {
if (!strstr(substr($session_data, $offset), "|")) {
throw new Exception("invalid data, remaining: " . substr($session_data, $offset));
}
$pos = strpos($session_data, "|", $offset);
$num = $pos - $offset;
$varname = substr($session_data, $offset, $num);
$offset += $num + 1;
$data = unserialize(substr($session_data, $offset));
$return_data[$varname] = $data;
$offset += strlen(serialize($data));
}
return $return_data;
}
private static function unserialize_phpbinary($session_data) {
$return_data = array();
$offset = 0;
while ($offset < strlen($session_data)) {
$num = ord($session_data[$offset]);
$offset += 1;
$varname = substr($session_data, $offset, $num);
$offset += $num;
$data = unserialize(substr($session_data, $offset));
$return_data[$varname] = $data;
$offset += strlen(serialize($data));
}
return $return_data;
}
}
?>
Usage:
<?php
Session::unserialize(session_encode());
?>
session_decode
(PHP 4, PHP 5, PHP 7, PHP 8)
session_decode — Dekodiert die Daten einer Session aus einer session-kodierten Zeichenkette
Beschreibung
session_decode() dekodiert die mittels
data übergebenen serialisierten Daten der Session
und füllt die $_SESSION-Superglobale damit.
Standardmäßig ist das verwendete Deserialisierungsverfahren ein PHP-internes, und nicht dasselbe ist, wie bei unserialize(). Das Serialisierungsverfahren kann mit der Konfigurationsoption session.serialize_handler festgelegt werden.
Parameter-Liste
-
data -
Die kodierten Daten, die gespeichert werden sollen.
Rückgabewerte
Gibt bei Erfolg true zurück. Bei einem Fehler wird false zurückgegeben.
Siehe auch
- session_encode() - Kodiert die Daten der aktuellen Session als session-kodierte Zeichenkette
- session.serialize_handler
add a note
User Contributed Notes 17 notes
Frits dot vanCampen at moxio dot com ¶
12 years ago
petej*shaman_ca ¶
21 years ago
Seems like there was a change in the behavior of this function somewhere between 4.1.2 and 4.3.3. In 4.1.2 session_decode() didn't care whether the session was started, and would just decode the string into the _SESSION array. In my 4.3.3 install, session_decode() wouldn't work unless I explicitly started the session with session_start().
frank at interactinet dot com ¶
11 years ago
I found this to be the simplest solution:
<?php
// if session is not started
session_start();
// store our current session
$my_sess = $_SESSION;
// decode $data (the encoded session data, either from a file or database). Remember, decoded data is put directly into $_SESSION
session_decode($data);
$data = $_SESSION;
print_r($data);
// restore our own session
$_SESSION = $my_sess;
?>
leon dot pegg at gmail dot com ¶
18 years ago
i have found this to be a better way to restore session data while keeping your current session.
function decode_session($session_string){
$current_session = session_encode();
foreach ($_SESSION as $key => $value){
unset($_SESSION[$key]);
}
session_decode($session_string);
$restored_session = $_SESSION;
foreach ($_SESSION as $key => $value){
unset($_SESSION[$key]);
}
session_decode($current_session);
return $restored_session;
}
enjoy
forum at orthanc dot co dot nz ¶
20 years ago
Becarful using this if you are trying to switch out of an existing session rather than load one into a clean slate.
session_decode doesn't destroy the existing session data, it will over write it if there is a session variable of the same name, but if the names don't clash the existing session variables will hang around.
I have yet to find a better solution than
session_destroy()
session_start()
session_decode(....);
-----------------------------------------
To explain what I'm talking about
<?
session_start();
$a = 5;
session_register('a');
session_decode("<session that doesn't have a as a session variable>");
print (session_is_registered('a') ? $a : 'Not Registered' );
?>
The above code will print '5' as $a hasn't been destroyed or even unregistered by the session_decode
davyvandenbremt at gmail dot com ¶
13 years ago
Here's what we are using to unserialize the session.
<?php
function unserialize_session($val) {
$result = array();
// prefixing with semicolon to make it easier to write the regular expression
$val = ';' . $val;
// regularexpression to find the keys
$keyreg = '/;([^|{}"]+)\|/';
// find all keys
$matches = array();
preg_match_all($keyreg, $val, $matches);
// only go further if we found some keys
if (isset($matches[1])) {
$keys = $matches[1];
// find the values by splitting the input on the key regular expression
$values = preg_split($keyreg, $val);
// unshift the first value since it's always empty (due to our semicolon prefix)
if (count($values) > 1) {
array_shift($values);
}
// combine the $keys and $values
$result = array_combine($keys, $values);
}
return $result;
}
?>
deminy at deminy dot net ¶
16 years ago
1. Reply to ac's post:
As I mentioned at http://us.php.net/manual/en/function.unserialize.php#76977 , the regular expression used to unserialize a PHP session data won't work if the session data contains string variable which contains character '|'.
Here is a simple example I just come up with to show when the function unserializesession() won't work.
<?php
function unserializesession($data) {
$vars=preg_split('/([a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff^|]*)\|/',
$data,-1,PREG_SPLIT_NO_EMPTY | PREG_SPLIT_DELIM_CAPTURE);
for($i=0; $vars[$i]; $i++) $result[$vars[$i++]]=unserialize($vars[$i]);
return $result;
}
session_start();
$_SESSION['var'] = 'a|b';
$str = session_encode();
$arr = unserializesession($str);
print_r($_SESSION);
echo "<br />\n";
print_r($arr);
?>
2. Reply to bmorel's post:
Your function session_real_decode() is very nice to decode session data without involving with session functions. It works in most cases, but when dealing with reference variables, there is another case which should also be handled:
<?php case 'r': /* reference */ // R in lowercase ?>
I found this bug on PHP 5.1.6 several months ago, but don't know if it exsits in other version of PHP or not. Also, I am not sure if similiar bugs exist when handling other data types.
So here is my suggestion to revise the function,
2.1.
change the switch statement from
<?php switch ($str[$q]) { ?>
to
<?php switch (strtolower($str[$q])) { ?>
2.2.
In all case statements, use lowercase characters only for character comparison. For example,
<?php case 'R': /* reference */ ?>
should be be written as
<?php case 'r': /* reference */ ?>
(I don't want to put long code here, so just leave pieces of code to save spaces)
sco at postmaster dot co dot uk ¶
20 years ago
If you're trying to access your session data from outside the regular php session functions, you might want to use WDDX as your serializer, as opposed to the normal php serializer. When your data is serialized as XML, obviously it's easy to unserialize as you please.
WDDX seems to be a little slower, and the text string it creates is much bigger than that created by the normal php serializer, but it provides the functionality with minimal hassle.
Donal
vesely at tana dot it ¶
19 years ago
When using this function to manage sessions, it is MUCH
better to have register_globals turned off. Then one can
examine the session content given its id.
<?php
$fname = session_save_path() . "/sess_" . $the_sid;
if (session_decode(file_get_contents($fname)))
{
$vars = $_SESSION;
$_SESSION = array();
// examine $vars...
}
?>
Depending on PHP version, you may need to have a dummy
session started for the code above to work. I reset the
$_SESSION immediately in order to avoid writing the
dummy session: that's needed while testing the code!
fabrizio dot messina at gmail dot com ¶
19 years ago
this function _really_ split and decode session data:
function unserializesession($data) {
$vars=preg_split('/([a-zA-Z0-9]+)\|/',$data,-1,PREG_SPLIT_NO_EMPTY | PREG_SPLIT_DELIM_CAPTURE);
for($i=0; $vars[$i]; $i++) {
$result[$vars[$i++]]=unserialize($vars[$i]);
}
return $result;
}
the difference from previously posted 'unserializesession' function is the regular expression inside function preg_split ('[a-zA-Z0-9]+' vs '[a-z,A-Z]+' )
jason at joeymail dot net ¶
13 years ago
Yet another attempt a wheel re-invention, using match with offsets rather than split...
<?php
function unserializesession( $data )
{
if( strlen( $data) == 0)
{
return array();
}
// match all the session keys and offsets
preg_match_all('/(^|;|\})([a-zA-Z0-9_]+)\|/i', $data, $matchesarray, PREG_OFFSET_CAPTURE);
$returnArray = array();
$lastOffset = null;
$currentKey = '';
foreach ( $matchesarray[2] as $value )
{
$offset = $value[1];
if(!is_null( $lastOffset))
{
$valueText = substr($data, $lastOffset, $offset - $lastOffset );
$returnArray[$currentKey] = unserialize($valueText);
}
$currentKey = $value[0];
$lastOffset = $offset + strlen( $currentKey )+1;
}
$valueText = substr($data, $lastOffset );
$returnArray[$currentKey] = unserialize($valueText);
return $returnArray;
}
?>
erwinmoller at xs4all dot nl ¶
19 years ago
The regExp-method describe earlier doesn't work under all conditions.
If I feed this:
voornaam|s:8:"Ai|;\'\"";achternaam|s:6:"werrwe";leeftijd|i:44;
I get this:
array(4) {
["voornaam"]=>
bool(false)
["Ai"]=>
bool(false)
["achternaam"]=>
string(6) "werrwe"
["leeftijd"]=>
int(44)
}
while I expected:
array(3) {
["voornaam"]=>
string(8) "Ai|;\'\""
["achternaam"]=>
string(6) "werrwe"
["leeftijd"]=>
int(44)
}
I think the | is messing things up. :-/
brett at brettbrewer dot com ¶
19 years ago
I have made a minor change to fabrizio's (et all) version of the unserializesession function because it was choking on underscores in my variable names. Here is the correct version which should account for ALL possible PHP variable names:
function unserializesession($data) {
$vars=preg_split(
'/([a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*)\|/',
$data,-1,PREG_SPLIT_NO_EMPTY |
PREG_SPLIT_DELIM_CAPTURE
);
for($i=0; $vars[$i]; $i++) {
$result[$vars[$i++]]=unserialize($vars[$i]);
}
return $result;
}
Please note that I had to split the preg_split function call above into 4 lines due to the limitations of this forum. This version changes the regex used to find variable names so that it complies with the specs for variable names as specified in the PHP manual at http://us3.php.net/manual/en/language.variables.php. I just took the regex directly from the PHP manual pages where they give the regex equivalent for a valid variable name as:
[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*
Anyway, this seems to work great for me now, even on gigantic strings of encoded session data.
ac ¶
17 years ago
this solved my | problem:
function unserializesession($data) {
$vars=preg_split('/([a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff^|]*)\|/',
$data,-1,PREG_SPLIT_NO_EMPTY | PREG_SPLIT_DELIM_CAPTURE);
for($i=0; $vars[$i]; $i++) $result[$vars[$i++]]=unserialize($vars[$i]);
return $result;
}
xueron at gmail dot com ¶
18 years ago
a perl reg:
$s = session_encoded_value;
%res = $s =~ /([a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*)\|([^\|]*[\;\}])/g;
njail ¶
20 years ago
<?PHP
// Get Session Content
$varsess = Array('SESSION');
for ($i = 0; $i < sizeof($varsess); $i++)
{
if (is_array(${"_{$varsess[$i]}"}))
{
foreach (${"_{$varsess[$i]}"} as $var=>$val)
{
$$var = $val;
// print "Var :".$var." -- Value :".$val."\n<br>";
}
}
unset(${"_{$varsess[$i]}"});
}
?>
nero321 at zmail dot sk ¶
18 years ago
Another solution for decoding session string to "$_SESSION"-like array:
<?php
// returns decoded string as arrays of variables
// or false on error (when session_decode returns false)
function DecodeSession($sess_string)
{
// save current session data
// and flush $_SESSION array
$old = $_SESSION;
$_SESSION = array();
// try to decode passed string
$ret = session_decode($sess_string);
if (!$ret) {
// if passed string is not session data,
// retrieve saved (old) session data
// and return false
$_SESSION = array();
$_SESSION = $old;
return false;
}
// save decoded session data to sess_array
// and flush $_SESSION array
$sess_array = $_SESSION;
$_SESSION = array();
// restore old session data
$_SESSION = $old;
// return decoded session data
return $sess_array;
}
?>
Example of use:
<?php
$sarr = DecodeSession($sess_str);
print_r($sarr);
?>
But I have not tested performance.
