dynamically name session isset how to use? - php

Question

I am trying to get dynamic $_SESSION[$id] on the second page shown below, but its not working (as per the printout):
First page url
https://example.com/test.php?id=1548393
First page code
<?php
session_start();
$id = $_GET['id'];
$_SESSION[$id] = "mysecretstringline";
?>
Second page url
https://example.com/test2.php?id=1548393
Second page code
<?php
session_start();
$id = $_GET['id'];
if(isset($_SESSION[$id])){
echo "working";
}else{
echo "not working";
}
?>

Answer 1

i found problem we can not use numeric index for $_SESSION
but we can use number in $_SESSION by convert number to roman numerals
first page url
https://example.com/test.php?id=1548393
first page code
<?php
session_start();
$roman_id = romanic_number($_GET['id']);
$_SESSION[$roman_id] = "mysecretstringline";
function romanic_number($integer, $upcase = true)
{
$table = array('M'=>1000, 'CM'=>900, 'D'=>500, 'CD'=>400, 'C'=>100, 'XC'=>90, 'L'=>50, 'XL'=>40, 'X'=>10, 'IX'=>9, 'V'=>5, 'IV'=>4, 'I'=>1);
$return = '';
while($integer > 0)
{
foreach($table as $rom=>$arb)
{
if($integer >= $arb)
{
$integer -= $arb;
$return .= $rom;
break;
}
}
}
return $return;
}
?>
second page url
https://example.com/test2.php?id=1548393
second page code
<?php
session_start();
$roman_id = romanic_number($_GET['id']);
if(isset($_SESSION[$roman_id])){
echo "working";
}else{
echo "not working";
}
function romanic_number($integer, $upcase = true)
{
$table = array('M'=>1000, 'CM'=>900, 'D'=>500, 'CD'=>400, 'C'=>100, 'XC'=>90, 'L'=>50, 'XL'=>40, 'X'=>10, 'IX'=>9, 'V'=>5, 'IV'=>4, 'I'=>1);
$return = '';
while($integer > 0)
{
foreach($table as $rom=>$arb)
{
if($integer >= $arb)
{
$integer -= $arb;
$return .= $rom;
break;
}
}
}
return $return;
}
?>
output
working
thanks #gre_gor and #Katie

Answer 2

Could be that in your normal code (this just looks like a quick mockup), you have a space after ?> somewhere. That could cause issues.
<?php
// start.php
session_start();
$id = $_GET['id'];
$_SESSION[$id] = "mysecretstringline";
and
<?php
// next.php
session_start();
$id = $_GET['id'];
if (isset($_SESSION[$id])) {
echo "working";
} else {
echo "not working";
}
works for me. Notice no ?> characters.
UPDATE:
The following might be of interest regarding session name constraints (can a php $_SESSION variable have numeric id thus : $_SESSION['1234’])
You have that issue in your example you could just add an id_ and then do the same check when validating/getting the session.