Sessions not getting updated

#1 (**permalink**) 02-29-2004

Hi,

I posted on this matter earlier with the subject line "Trouble with
sessions," but someone else started a different thread with the same
subject line that arrived before my post, so I'm changing my subject
line in order to avoid confusion.

I was asked to provide a code example for analysis, so here it is,
along with a
a description of what the problem is.

I'm working with sessions and the values for HTML text fields
(input="text") aren't getting updated after the first time I submit
the form. If I shut down my browser and start anew, I can write to the
session just once, as before. On the other hand, radio buttons -- used
with the Sticky Multivalued Parameters script on pages 170-171 of
O'Reilly's "Programming PHP" -- are updated every time. Here's an
example of my code. Many thanks to anyone who can make sense of what's
going on here.

Best wishes,

Mountain Man

<html>
<head>
<title>First Form Sessions</title>
</head>
<body>
<form action="form_processor.php4" method="POST">
First Name: <input type="text" name="firstName" value="<?php echo
$firstName ?>" /><br />
<input type="submit" />
</form>

</body>
</html>

// Next, the form processing script which is on another page.
// In my more complex script of actual use the form is only
// included if it doesn't pass validation.

<?php
session_start();
session_register("firstName");
?>

<html>
<head>
<title>Form Processor Sessions</title>
</head>
<body>

<?php
echo "$firstName<br />";
include 'first_form.php4';
?>

</body>
</html>

#2 (**permalink**) 02-29-2004

Mountain Man wrote:
> I'm working with sessions and the values for HTML text fields
> (input="text") aren't getting updated after the first time I submit
> the form. If I shut down my browser and start anew, I can write to the
> session just once, as before. On the other hand, radio buttons -- used
> with the Sticky Multivalued Parameters script on pages 170-171 of
> O'Reilly's "Programming PHP" -- are updated every time. Here's an
> example of my code. Many thanks to anyone who can make sense of what's
> going on here.
>

Using php version >= 4.1? Then start using the $_SESSION superglobal:

<?

// Enable sessions
session_start();

// Get the page URL
$page = $_SERVER['PHP_SELF'];

// Destroy the session var
if (isset($_GET['unset'])) {
if (isset($_SESSION['test'])) {
unset($_SESSION['test']);
header("Location: $page");
exit;
}
}

// Update/create the session var
if (isset($_SESSION['test'])) {
$_SESSION['test']++;
} else {
$_SESSION['test'] = 1;
}

// Debug output
print "test = {$_SESSION['test']}<br />";
print "<a href='$page?unset=1'>Destroy session</a>";

?>

JW

#3 (**permalink**) 03-01-2004

Hi mountain man:

(from)
http://nl.php.net/manual/en/function.session-start.php

---------------------------
session_start

(PHP 4 )
session_start -- Initialize session data
Description
bool session_start ( void )

session_start() creates a session or resumes the current one based on the
current session id that's being passed via a request, such as GET, POST, or
a cookie.

This function always returns TRUE.

Note: If you are using cookie-based sessions, you must call
session_start() before anything is outputted to the browser.
---------------------------

Read that nore carefully.
Your code calls session_start halfway your script, AFTER output, so correct
that first before anything else.
Futhermore I see that you are echoing $firstName without initializing it.
Did you put the (retarded) register globals on in your php.ini?
Don't, it is bad.
Modern php comes with registerglobals off by default.

Better is this:
$firstName = $_GET["firstName"]
or
$firstName = $_POST["firstName"]

or even better:
$firstName = (isset($_GET["firstName"]) ? $_GET["firstName"]: "unkown")

Regards,
Erwin Moller

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