foreach() Error on Session Values

PCHomepage · Mar 7, 2009

I have a little diagnostics script that fetches server, session and cookie info and it works well on my live server. It also worked well on my development system until I switched recently to Linux (Ubuntu 8.10) where the line that gives the session values generates an error.

Code:

<html>
<head>
</head>
<body>
<?php
$s = "<h4>Server Values</h4>";
foreach($_SERVER as $key=>$value)
$s = $s . "<b>" . $key . "</b> = " . $value . "<br>";

$s = $s . "<p><h4>Session Values</h4>";
[COLOR=red]foreach($_SESSION as $key=>$value)[/color]
$s = $s . "<b>" . $key . "</b> = " . $value . "<br>";

$s = $s . "<p><h4>Cookie Values</h4>";
foreach($_COOKIE as $key=>$value)
$s = $s . "<b>" . $key . "</b> = " . $value . "<br>"; 

$s = $s . "<p><h4>GD Support</h4>";
foreach(gd_info() as $key=>$value)
$s = $s . "<b>" . $key . "</b> = " . $value . "<br>"; 

//$s = $s . "<p><h4>PHP Details</h4>";
//foreach(phpinfo() as $key=>$value)
//$s = $s . "<b>" . $key . "</b> = " . $value . "<br>"; 

echo $s;
?>
</body>
</html>

The actual error is "Invalid argument supplied for foreach()." Any ideas?

DonQuichote · Mar 7, 2009

Sure. $_SESSION probably does not even exist if you do not do a session_start first.

+++ Despite being wrong in every important aspect, that is a very good analogy +++
Hex (in Darwin's Watch)

PCHomepage · Mar 7, 2009

That's a possibility but, as the session was started by another page on the same site, I didn't think it needed to be started again. Does it? The same exact script never needed it before but you're right. Adding a link to the included session file did indeed fix the problem. Thanks!

Code:

<?php
include_once(getenv("DOCUMENT_ROOT") . "/includes/functions.inc");
?>

This script includes this function, among others:

Code:

<?php
function my_session_start() {
 	if (isset($_COOKIE['PHPSESSID'])) {
		$sessid = $_COOKIE['PHPSESSID'];
	} else if (isset($_GET['PHPSESSID'])) {
		$sessid = $_GET['PHPSESSID'];
	} else {
		session_start();
		return false;
	}
       
	if (!preg_match('/^[a-z0-9]{32}$/', $sessid)) {
		return false;
	}
	session_start();
 	return true;
}

my_session_start();
?>

vacunita · Mar 7, 2009

You need to execute session_start(); in every page you need to have sessions in.

----------------------------------
Phil AKA Vacunita
----------------------------------
Ignorance is not necessarily Bliss, case in point:
Unknown has caused an Unknown Error on Unknown and must be shutdown to prevent damage to Unknown.

PCHomepage · Mar 7, 2009

Interesting! I never had to do that before. It is my guess that my new setup does not have the Apache session auto-start setting enabled.

DonQuichote · Mar 8, 2009

It is not an Apache setting but a PHP setting. But there is nothing wrong with issuing session_start for each page that needs it. It is how PHP works. If you want your code to be as independent as possible on the server settings, don't rely on automagic features like that.

Also a warning: session_start sends extra HTTP headers (to avoid caching). This is usually OK, but if you send "do-cache" headers (because IE needs them) do so AFTER the session_start or they will be overwritten without even a notice.

+++ Despite being wrong in every important aspect, that is a very good analogy +++
Hex (in Darwin's Watch)

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foreach() Error on Session Values

PCHomepage

Programmer

DonQuichote

Programmer

PCHomepage

Programmer

vacunita

Programmer

PCHomepage

Programmer

DonQuichote

Programmer

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