Unable to set session under switch/case condition - php

Question

I am unable to set session for $_SESSION['next'] under switch/case condition, while $_SESSION['user_id'] works perfectly before the condition. The script run into each condition of switch/case condition and redirect without setting $_SESSION['next']. Is there any specific reason why it fails to work? How to solve this?
require_once ('../src/facebook.php');
require_once ('../src/fbconfig.php');
//Facebook Authentication part
$user_id = $facebook->getUser();
if ($user_id <> '0' && $user_id <> '') {
session_start();
$_SESSION['user_id'] = $user_id;
switch((isset($_GET['page']) ? $_GET['page'] : '')){
case 'abc';{
$_SESSION['next'] = 'AAA';
echo "<script>top.location.href = 'https://www.example.com/xxx/'</script>";
exit;}
case 'def';{
$_SESSION['next'] = 'BBB';
echo "<script>top.location.href = 'https://www.example.com/xxx/'</script>";
exit;}
case 'ghi';{
$_SESSION['next'] = 'CCC';
echo "<script>top.location.href = 'https://www.example.com/xxx/'</script>";
exit;}
default;{
echo "<script>top.location.href = 'https://www.example.com/xxx/'</script>";
exit;}
}
} else {
echo "<script>top.location.href = 'https://www.example.com/xxx/'</script>";
exit;
}

Answer 1

Your switch is all wrong. Read the manual and try this:
<?php
switch ((isset($_GET['page']) ? $_GET['page'] : '')){
case 'abc':
$_SESSION['next'] = 'AAA';
echo "<script>top.location.href = 'https://www.example.com/xxx/'</script>";
break;
case 'def':
$_SESSION['next'] = 'BBB';
echo "<script>top.location.href = 'https://www.example.com/xxx/'</script>";
break;
case 'ghi':
$_SESSION['next'] = 'CCC';
echo "<script>top.location.href = 'https://www.example.com/xxx/'</script>";
break;
default:
echo "<script>top.location.href = 'https://www.example.com/xxx/'</script>";
break;
}
You're using exit in your switch, which (unless you want your script to end at the switch) is a no-no. Instead, you have to use the break keyword.
You also use semicolons and curly braces for each case.
case 'ghi';{ ... }
NO! Proper usage is
case 'ghi':
.
.
.
break;
Update: I just noticed you use this line:
if ($user_id <> '0' && $user_id <> '') { ... }
What is <> doing in PHP code? The "standard" operator for "not equals" is != in PHP. Use it correctly or no one will want to use your code.
Second update: You never set $_SESSION['next'] in your default case. It's very likely that your switch is always going to the default case. This would cause the behavior you're experiencing.

Answer 2

I suggest:
if (($user_id != '0') && ($user_id != ''))
(parentheses, and the != operator)
and also a DRYer switch:
$page = array_key_exists('page', $_GET) ? $_GET['page'] : '';
switch ($page) {
case 'abc':
$next = 'AAA';
$loc = 'https://www.example.com/xxx/';
break;
case 'def':
$next = 'BBB';
$loc = 'https://www.example.com/yyy/';
break;
... // and so on
}
if (isset($next)) {
$_SESSION['next'] = $next;
// If it does not work, you have problems with your session ID, maybe?
}
// I find this syntax easier
print <<<SCRIPT
<script type="text/javascript">
top.location.href = '$loc';
</script>
SCRIPT;
exit();