php session_id()

christg · 29-02-2012 08:55PM #1

hello all, I have a 4 page form that I'm trying to save the form fields till the last page till I post it all to the database. I was thinking that $_SESSION would be the best way to go.

Problem is that no matter how I do it, there is no info in this variable when I go to the next page. I checked the session_id() and it is different for each page that I go to. I'm using the <form id="form1" name="form1" method="post" action="page4.php"> at the beggining of the form and I finish with
<tr>
<td align="center"><input type="submit" value="Next Page" size="60" /></td>
</tr>

The php looks like for page 1
</div>
<?php
session_start();
$_SESSION = 1;
echo "Pageviews = ". $_SESSION . ' ';
echo session_id().' ';
$HTTP_SESSION_VARS = "hello world";
echo 'The content of $HTTP_SESSION_VARS[\'sess_var\'] is '.$HTTP_SESSION_VARS. ' ';
$_SESSION = $_POST;
echo $_SESSION;
echo 'this is the end of php';
?>
</html>
************************************
and page 2 looks like
</body>
<?php
session_start();
echo "Pageviews = ". $_SESSION . ' ';
echo session_id().' ';
echo $_SESSION.' ';
echo 'The content of $HTTP_SESSION_VARS[\'sess_var\'] is '.$HTTP_SESSION_VARS. ' ';

echo "Pageviews = ". $_SESSION.' ';
echo $_SESSION.' ';
echo 'this is the end of php';
?>
</html>
*************************************************
the results I get are for the first page
Pageviews = 1
a098a52a745dd51835618fd2d6d0d0b4
The content of $HTTP_SESSION_VARS is hello world
jack
this is the end of php
***********************************
for the second page
Pageviews =

The content of $HTTP_SESSION_VARS is
Pageviews =

this is the end of php

christg · 29-02-2012 09:57PM

I moved my <a href> after my php and I get the session id put into the url, which I don't like, and it seems to work. But if my <a href> is before my php code I get different session id's
********************************
test1.php
********************************
<html>
<head>
</head>
<body>
</body>
<?php
session_start();
$_SESSION = 'chris';
echo $_SESSION.' ';
echo session_id().' ';
?>
<a href='test2.php'>Next Page</a>
</html>
*****************************************
test2.php
*****************************************
<html>
<head>
</head>
<body>
</body>
<?php
session_start();
echo $_SESSION.' ';
echo session_id().' ';
?>
<a href='test3.php'>Next Page</a>
</html>
**************************************
test3.php
**************************************
<html>
<head>
</head>
<body>
</body>
<?php
session_start();
echo $_SESSION.' ';
echo session_id().' ';
?>
</html>
***********************************
gives my the following results:
http://www.cgreaney.com/school/test1.php
***********************************
chris
fe1ab197c9fde266b690a3e9cc657798
Next Page
************************************
http://www.cgreaney.com/school/test2.php?PHPSESSID=fe1ab197c9fde266b690a3e9cc657798
*************************************
chris
fe1ab197c9fde266b690a3e9cc657798
Next Page
*************************************
http://www.cgreaney.com/school/test3.php?PHPSESSID=fe1ab197c9fde266b690a3e9cc657798
*************************************
chris
fe1ab197c9fde266b690a3e9cc657798
*************************************
so the results all look good, but I don't like the url having the session id in it.
If I move my <a href> like:
<html>
<head>
</head>
<body>
<a href='test2.php'>Next Page</a>
</body>
<?php
session_start();
$_SESSION = 'chris';
echo $_SESSION.' ';
echo session_id().' ';
?>
</html>
I get the following output:
Next Page chris
b5fbc524d4a8475f8bd609c0d25c1ab2
***********************************
Next Page
47c1a4acc4ffea036a9712ad80890a90
***********************************
The url stays with just the page name, but I loose my $_SESSION variable and the session ID changes.

Liam Byrne · 29-02-2012 10:00PM

session_start should be before any output; in fact, if you didn't have errors & warning suppressed, it's probably throwing an error.

christg · 29-02-2012 10:38PM

By any output, are you meaning the html parts ? since I have the session_start() right after <?php.

I was thinking that maybe I should move the php section to the top of the page before the html.

Thanks for the timely reply !

Webmonkey · 29-02-2012 11:00PM

christg wrote: »

By any output, are you meaning the html parts ? since I have the session_start() right after <?php.

I was thinking that maybe I should move the php section to the top of the page before the html.

Thanks for the timely reply !

yes, since the session data is included in the http header, it's too late to include it in the header if HTML (in your case) is already outputted.

Then there's ob_start if you want to cache the http content while sending the headers

christg · 29-02-2012 11:04PM

Thanks all, it makes sense now. I didn't see any warning on this in all of the tutorials I looked at.

Does it make sense to use the session variables to store form information until the last page of the form where I input it into a database ?

I thought I might be able to do it with the form action posting it to the last page.

php session_id()

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