Getting $_GET variable when using mod_rewrite - php

Question

I am having issues getting $_GET variables with mod_rewrite enabled. I have the following .htaccess:
RewriteEngine On
RewriteRule ^/?Resource/(.*)$ /$1 [L]
RewriteRule ^$ /home [redirect]
RewriteRule ^([a-zA-Z]+)/?([a-zA-Z0-9/]*)$ /app.php?page=$1&query=$2 [L]
and app.php is:
<?php
require("controller.php");
$app = new Controller();
and controller.php is:
<?php
require("model.php");
require("router.php");
class Controller{
//--------Variables------------
private $model;
private $router;
//--------Functions------------
//Constructor
function __construct(){
//initialize private variables
$this->model = new Model();
$this->router = new Router();
$page = $_GET['page'];
//Handle Page Load
$endpoint = $this->router->lookup($page);
if($endpoint === false) {
header("HTTP/1.0 404 Not Found");
}else {
$this->$endpoint($queryParams);
}
}
private function redirect($url){
header("Location: /" . $url);
}
//--- Framework Functions
private function loadView($view){
require("views/" . $view . ".php");
}
private function loadPage($view){
$this->loadView("header");
$this->loadView($view);
$this->loadView("footer");
}
//--- Page Functions
private function indexPage(){
$this->loadPage("home");
}
private function controlPanel(){
echo "Query was " . $code;
/*
if($this->model->set_token($code)){
$user = $this->model->instagram->getUser();
}else{
echo "There was an error generating the Instagram API settings.";
}
*/
$this->loadPage("controlpanel");
}
private function autoLike(){
$this->loadPage("autolike");
}
private function about(){
$this->loadPage("about");
}
}
So an example of a URL that I might have is /app.php?page=controlpanel&query=null which would be rewritten as /controlpanel. The problem I have is that I have another page which sends a form to /controlpanel resulting in a URL like /controlpanel?code=somecode.
What I am trying to do is get $_GET['code'] and I cannot seem to do this. Can anyone help? Apologies in advance for a bit of a code dump.

Answer 1

Change
RewriteRule ^([a-zA-Z]+)/?([a-zA-Z0-9/]*)$ /app.php?page=$1&query=$2 [L]
to
RewriteRule ^([a-zA-Z]+)/?([a-zA-Z0-9/]*)$ /app.php?page=$1&query=$2 [L,QSA]
QSA is to append the query string
From the docs
"When the replacement URI contains a query string, the default behavior of RewriteRule is to discard the existing query string, and replace it with the newly generated one. Using the [QSA] flag causes the query strings to be combined."