added route for token backup

imaginaerraum_door_admin/webapp.py

@@ -529,6 +529,19 @@ def create_application(config):
                 flash(f"Error during store_tokens. Exception: {e}")
         return redirect('/tokens')
 
+    @app.route('/backup_tokens')
+    @auth_required()
+    def backup_tokens():
+        # get list of defined admin users for backup
+        tokens = door.get_tokens()
+        try:
+            with tempfile.TemporaryDirectory() as tmpdir:
+                file = Path(tmpdir, 'token_data.txt')
+                file.write_text(json.dumps(tokens))
+                return send_file(file, as_attachment=True, cache_timeout=-1)
+        except Exception as e:
+            return str(e)
+
     @app.route('/open')
     @auth_required()
     def open_door():