fix

Backend/Controllers/FileHandler/upload.php

@@ -1,7 +1,8 @@
 <?php
 require_once "../../../bootstrap.php";
+require_once('../Group/Group.php');
 use Backend\Models\GameData;
-use function Backend\Controllers\groupViaToken;
+
 use Backend\Models\Group;
 
 $isImages = false;

Backend/Controllers/Group/Group.php

@@ -1,6 +1,5 @@
 <?php
-namespace Backend\Controllers;
-require "../../../bootstrap.php";
+require_once "../../../bootstrap.php";
 
 use Backend\Models\Group;
 use Backend\Models\Password;
@@ -12,6 +11,12 @@ use Backend\Models\Password;
 
 function groupViaToken(string $token){
 
-    $password = Password::firstWhere('remember_token', $token);
-    return Group::find($password->group_id);
+    if($password = Password::firstWhere('remember_token', $token)){
+        return Group::find($password->group_id);
+    }
+    return null;
+}
+
+function isLogin(){
+    return isset($_SESSION["token"]);
 }

Frontend/index.php

@@ -1,3 +1,9 @@
 <?php
+session_start();
+
+echo strlen($_SESSION['token']),  PHP_EOL;
+echo bin2hex($_SESSION['token']), PHP_EOL;
+
+
 
 print_r($_GET);