PHP Sessions/Cookies On The Fly

This article shows how to save and modify php session data, cookies, do anything really... without using ajax or iframes or forcing the user make a request.

Warning: Touches on some moderately advanced web development, definately some very cool stuff though.

.htaccess mod_rewrite code

This code turns a request for askapache.com/sess.gif to serve the file /cgi-bin/session-cookie.php - further disguising this "image".

RewriteEngine On
RewriteBase /
RewriteRule ^(.*)session.gif$ /cgi-bin/session-cookie.php [NC,L,QSA]

Using javascript

You can either put a basic img tag somewhere and it will capture this info, or if you want a dynamic way to call this image, you can do it with javascript very easily.

This code loads a new image as soon as this code is executed.. so you could quite easily add this code to be executed upon a certain button click, anything.

	var t=new Image();
	t.src='https://www.askapache.com/sess.gif';

The php controller

This file has some cool stuff in it, check it out. First we check to see if a session has been initialized and if not we start a session. Then we initialize an output buffer to hold all the output including the headers until we are ready to send output, the only output we will be sending is a 43 byte 1x1 white image. The code also sends HTTP headers that prevent the clients browser from caching the image, so a new request is made for the image each time a browser encounters it.

The data we will be saving in the users session file using the session variable called IMAGETEST are the entire $_GET, $_COOKIE, $_POST, and $_SERVER global variable arrays builtin to php.

$G,'SERVER'=>$S))));
$_SESSION['IMAGETEST']=$g;

$imagedata=base64_decode('R0lGODlhAQABAIAAAP///wAAACH5BAAAAAAALAAAAAABAAEAAAICRAEAOw==');

header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
header("Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0");
header("Pragma: no-cache");
header('Content-Length: 43');
header('Content-Type: image/gif');
echo $imagedata;

$r=ob_get_clean();
echo $r;
exit;
?>

The result from requesting the php file is a session variable is created called IMAGETEST that contains a base64 encoded and gzip compressed and php serialized string representing the $_REQUEST and $_SERVER variables for that specific request.

Example Session IMAGETEST value

 [IMAGETEST] => eJy1Vm1vo0YQ/ivIUqu7Orws78ZCKrKxg842LuBE1y9ogSVBscEFnERX33/vsIDj5NK75NQqcoDd2Zln3p5ZbIjG35UhGYO5HQzG2ED9d5KVg

Decoding the IMAGETEST

So to see the values of IMAGETEST if you used my method to compress and save the data as a string, is basically to run the string through the same process backwards.

';
$p=unserialize(gzuncompress(base64_decode($_SESSION['IMAGETEST'])));
print_r($p);
?>

This results in displaying all the variables and data you saved.

Array
(
[REQUEST] => Array
(
[ASKAPACHE] => 6a81995f0c4b73b4d
[MP3] => off
[subscribe_checkbox_0460e1098afa8bf8b] => unchecked
[wordpresspass_5510982bf8b] => 6555555
[wordpressuser_0559828bf8b] => youdliketoknow
[wordpress_test_cookie] => WP Cookie check
)

[SERVER] => Array
(
[PATH] => /usr/local/bin:/usr/bin:/bin
[REDIRECT_STATUS] => 200
[SCRIPT_URL] => /sess.gif
[SCRIPT_URI] => https://www.askapache.com/sess.gif
[TZ] => America/Las_Vegas
[SERVER_ADMIN] => webmaster[at]askapache.com
[HTTP_HOST] => www.askapache.com
[HTTP_USER_AGENT] => Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.13) Gecko/20080311 Firefox/2.0.0.13
[HTTP_ACCEPT] => image/png,*/*;q=0.5
[HTTP_ACCEPT_LANGUAGE] => en-us,en;q=0.5
[HTTP_ACCEPT_ENCODING] => gzip,deflate
[HTTP_ACCEPT_CHARSET] => ISO-8859-1,utf-8;q=0.7,*;q=0.7
[HTTP_KEEP_ALIVE] => 300
[HTTP_CONNECTION] => keep-alive
[HTTP_REFERER] => https://www.askapache.com/online-tools/htpasswd-generator/
[HTTP_COOKIE] => 405485
[SERVER_SIGNATURE] =>
[SERVER_SOFTWARE] => Apache/2.0.61 (Unix) PHP/4.4.7 mod_ssl/2.0.61 OpenSSL/0.9.7e mod_fastcgi/2.4.2 DAV/2 SVN/1.4.2
[SERVER_NAME] => www.askapache.com
[SERVER_ADDR] => 208.113.183.103
[SERVER_PORT] => 80
[REMOTE_ADDR] => 2.12.64.105
[DOCUMENT_ROOT] => /web/domain.com/public_html
[SCRIPT_FILENAME] => /web/domain.com/public_html/cgi-bin/session-cookie.php
[REMOTE_PORT] => 1857
[REDIRECT_QUERY_STRING] => dir=
[REDIRECT_URL] => /cgi-bin/session-cookie.php
[GATEWAY_INTERFACE] => CGI/1.1
[SERVER_PROTOCOL] => HTTP/1.1
[REQUEST_METHOD] => GET
[QUERY_STRING] => dir=
[REQUEST_URI] => /sess.gif
[SCRIPT_NAME] => /cgi-bin/session-cookie.php
[ORIG_PATH_INFO] => /cgi-bin/session-cookie.php
[ORIG_PATH_TRANSLATED] => /web/domain.com/public_html/cgi-bin/session-cookie.php
[PHP_SELF] => /cgi-bin/session-cookie.php
[REQUEST_TIME] => 1206697334
)

)

Simpler php example