Using Url Query's to define page

The web page i want to go to is

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I have a file called projects.php that looks for variables and includes the correct page (projectsm projectdetails, projectedit...) But i don't know how to make the script detect if there is a page definition (`?action=projectdetails`) The `&id` variable tells to server what id to query on the database to retrieve information.

Here is my current code (which doesn't work)

<?php
session_start();
ob_start();
$currentPage = 'usrprojects';

require ('assets/config.inc.php');


if (isset($_SESSION['logged_in']) != true) {
header("location: login.php");
}
else {
if (isset($_GET['action'])){
if( isset($_GET['projectdetails']) && $_GET['projectdetails'] == "")
{
echo "asd";
}
}
else {
require 'includes/pages/projects.php';
}
}
?>

I think the above would more likely be like this as you are trying to find if a GET variable is equal to `projectdetails` rather than find a GET variable with the name `projectdetails`

session_start();
ob_start();
$currentPage = 'usrprojects';

require ('assets/config.inc.php');


if ( isset( $_SESSION['logged_in'] ) != true ) {
header( 'location: login.php' );
} else {
if ( isset( $_GET['action'] ) ){
if( $_GET['action'] == 'projectdetails' ) require 'includes/pages/projects.php';
else echo 'asd';
}
}

However, as I mentioned in the comment you might want to use a whitelist idea - rough idea like this:



session_start();
ob_start();

if( empty( $_SESSION['logged_in'] ) ){
exit( header( 'location: login.php' ) );
}

$whitelist=array(
'projects' => array('script'=>'includes/pages/projects.php','level'=>3),
'admin' => array('script'=>'includes/pages/admin.php','level'=>1),
'other' => array('script'=>'includes/pages/other.php','level'=>5)
);

$currentPage = 'usrprojects';
require ('assets/config.inc.php');



if( !empty( $_GET['action'] ) && array_key_exists( $_GET['action'], $whitelist ) ){

$action = $whitelist[ $_GET['action'] ]['script'];
$level = $whitelist[ $_GET['action'] ]['level'];

if( file_exists( $action ) && $_SESSION['level'] <= $level ) require $action;
}