New "Invite" feature implemented

app/main/controller/controller.php

@@ -256,4 +256,39 @@ class Controller {
         return $data;
     }
 
+
+    /**
+     * function is called on each error
+     * @param $f3
+     */
+    public function showError($f3){
+
+        // set HTTP status
+        if(!empty($f3->get('ERROR.code'))){
+            $f3->status($f3->get('ERROR.code'));
+        }
+
+        if($f3->get('AJAX')){
+            header('Content-type: application/json');
+
+            // error on ajax call
+            $errorData = [
+                'status' => $f3->get('ERROR.status'),
+                'code' => $f3->get('ERROR.code'),
+                'text' => $f3->get('ERROR.text')
+            ];
+
+            // append stack trace for greater debug level
+            if( $f3->get('DEBUG') === 3){
+                $errorData['trace'] = $f3->get('ERROR.trace');
+            }
+
+            echo json_encode($errorData);
+        }else{
+            echo $f3->get('ERROR.text');
+        }
+
+        die();
+    }
+
 }