SessionID Not Consistent?

jbutler

Session ID seems to be getting reinitialized during a "session". I can find no specific details about how...exactly...sessions are treated by PHP. I understand passing it via URL and using cookies, and I understand hidden (=SID) and visible id's, but what...exactly...initializes a session?

Sample: <a href="page.html?id=<?echo $id?>">

That's the code I'm using in every hyperlink on a test site. Every page includes a PHP file which starts a session and assigns the session id to the "$id" variable:

if (!$id) {
session_register('id');
session_start();
$id = session_id();
}

When I look at my log file, after surfing around on the site a bit, I see that my session id has changed during the surfing. I can see no consistency in why it would change, as sometimes it changes on "page1" and sometimes not.

Also, if someone else comes into the test site while I'm surfing it, they might very well get MY session id for a few seconds!

So:
1) What does PHP look for, and where does it look, when deciding whether or not to begin a new session?
2) In the absence of cookies, what are some rules of thumb for guaranteeing that a session stays consistent for the life of a visit, and ONLY for that one visitor?

I really appreciate any help with this.
Thanks!

kikidonc

Hi,

I don't know if I got correctly your problem but:

Before your if statement, do you open a session??? (I suppose so, otherwise you couldn't test $id).

In that case why do you open a new session in the if statement??? It's maybe the cause of your trouble.... new session probably means a new id ...

Fred.

jbutler

Here's how I arranged it (loosely):

"track.php" =======

<?php
if (!$id) { # only if $id is null/not init
session_register('id'); # init $id
session_start(); # start session
$id=session_id(); # apply value
}
?>

"page1.html" (and all other pages) =======

....
<head><?include ("track.php")?>...
<body>...
<a href="page2.html?id=<?echo $id?>">link</a>

(No problem parsing .html files with php)

I am now looking to make sure that every single link, whether on the page, in a form, or coming from a script result has the php code appended to it.

I am also meticulously going through every page to be sure that there are no absolute paths in any of the links that need php.

I need to carry the session_id in the URL like this so that the code gets written to the transfer.log, which is where we get our stats and visitor paths from.

I have this code on every page to (a) carry over the session_id throughout the visit, and (b) to get the session started regardless of where the visitor enters the site.

===
It is clear that php makes the connection between the URL argument (id=) and the php variable ($id). This indicates that php is reading and interpreting stuff with its engine.

Where can I find php information with detail about the engine itself, not just how to apply code? I don't want to hack it...just to better understand it.

Thanks, again!