Re: [PHP] IsSet() and $_SESSION - BUG?

Mon, 30 Jun 2003 21:47:43 -0700

Hello everyone. I was able to determine what was causing my problem with session variables not being persitant across page requests. I want to give you the full scope here, so I'm going to paste the code (and if you have any code tips, please let me know). I think the problem might be this (and I don't know why it should be, but maybe you can help):
If you look at file2.php, you will see that ValidAdminLogin() contains the "global $_SESSION;" declaration., but that's not the problem.
ValidAdminLogin() calls a function ResetSessionVariables(), which also contains "global $_SESSION;". When "global $_SESSION;" is present in ResetSessionVariables(), it seems as though the $_SESSION variables are not being preserved across page requests (notice that ResetSessionVariables() is called BEFORE the variables are set with the real data, but it's really $_SESSION['uid'] we are concerned with.)
When I remove "global $_SESSION;" from ResetSessionVariables(), all works fine across page request. Also note that $_SESSION['uid'] is set when we return from the file2.php function calls as noted in the "echo" command. So, why would a double global definintion negate $_SESSION?


------------------------------------ file1.php  -------------------------
<?php
session_start();
include "include/DatabaseConnect.php";
include "include/commonphp.php";
DisableClientCaching();

if (!isset($_SESSION['uid'])) {
if ( !ValidAdminLogin($_POST['adminid'],$_POST['adminpass'])){ forceadminlogin(); } } elseif ( !ValidAdminSession() ){
// Not a valid admin session - redirect forceadminlogin();
} ?>
<html>
<body>
<?php
//We always get a value for this, but it get lost when we leave the page.
echo $_SESSION['uid'];
?>
<br><br><br><br>
<center>
<a href='additem.php'>Add Item</a>
</center>
</body>
</html>
--------------------------------------- file2.php --------------------------
<?php

include "configvars.php";

function ValidAdminSession(){
   global $_SESSION;
   if ( isset($_SESSION['adminlogin']) ){ return 1; }
   else { return 0;}
}

function DisableClientCaching(){
header("Expires: " . gmdate("D, d M Y H:i:s") . " GMT"); // Expire now
header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT"); // always modified
header("Cache-Control: no-store, no-cache, must-revalidate"); // HTTP/1.1
header("Cache-Control: post-check=0, pre-check=0", false); // HTTP/1.0
header("Pragma: no-cache"); // HTTP/1.0
}

function ResetSessionVariables(){

// WHEN I REMOVE THIS LINE, EVERYTHING WORKS FINE
// global $_SESSION;
$_SESSION['uid'] = session_id();
$_SESSION['username'] = '';
$_SESSION['adminlogin'] = False;
$_SESSION['fname'] = '';
$_SESSION['lname'] = '';
$_SESSION['email'] = '';
$_SESSION['errormesg'] = '';
}

function ValidAdminLogin($user, $pass){

global $_SESSION;
include "DatabaseConnect.php";
mysql_connect($DBAddress,$DBUser,$DBPassword);
@mysql_select_db($DBDatabase) or die("ERROR");
$query="SELECT * FROM adminuser WHERE user='" . $user ."' AND pass='" . md5($pass) . "'";
$results = mysql_query($query);
$num = mysql_numrows($results);

if ($num != 1){
$returnvar = false; // Make sure the user exist, and is only one (even though it's a unique SQL field)
} else {
ResetSessionVariables();

       $_SESSION['username'] = strtolower(formatformdata($user));
       $_SESSION['adminlogin'] = True;
       $_SESSION['fname'] = mysql_result($results,0,"fname");
       $_SESSION['lname'] = mysql_result($results,0,"lname");
       $_SESSION['email'] = mysql_result($results,0,"email");
       $_SESSION['uid'] = session_id();

$returnvar = true;
}
return $returnvar;
mysql_close(); }

function forceadminlogin(){
       ResetSessionVariables();
       header("Location: AdminLogin.php");
}

function formatformdata($mystring){
return addslashes(rawurldecode(chop($mystring))); }
?>




John Manko wrote:

I'm having a problem with the value that isset returns on $_SESSION
variables.  For some reason, even if $_SESSION['uid'] is set, isset
returns FALSE.  Here is the code:

------ file1.php -----------
include "file2.php";

if (!isset($_SESSION["uid"])) {
// This first time $_SESSION["uid"] is check, we should
// end up in here. However, ValidAdminLogin (next test)
// will set $_SESSION["uid"] so next time we will not
// get here. if ( !ValidAdminLogin($_POST["adminid"],$_POST["adminpass"]))
forceadminlogin();

} elseif ( !ValidAdminSession() )
forceadminlogin();


// this is done to show that $_SESSION["uid"] is being set
// but isset still returns false
echo $_SESSION["uid"];

------ file2.php -----------
function ValidAdminLogin($user, $pass){
global $_SESSION;

    if (The_MYSQL_Stuff_Is_NOT_OK)     return false;
    else
    {
         session_start();

      $_SESSION["logged"] = true;
      $_SESSION["username"] = $user;
      $_SESSION["adminlogin"] = true;
      $_SESSION["fname"] = $fname;
      $_SESSION["lname"] = $lname;
      $_SESSION["email"] = $email;
      $_SESSION["uid"] = session_id();

          return true;
    }

mysql_close(); }







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