fix a bug

Rodin.py

@@ -125,12 +125,15 @@ def load_image(img_path):
 class Generator:
     def __init__(self, user_id, password) -> None:
         _, self.token = login(user_id, password)
+        self.user_id = user_id
+        self.password = password
         self.task_uuid = None
         
     def preprocess(self, prompt, image_path, cache_image_base64, task_uuid=""):
         if cache_image_base64 and prompt and task_uuid != "":
             return prompt, cache_image_base64
         print("Preprocessing image...")
+        _, self.token = login(self.user_id, self.password)
         
         image_file = load_image(image_path)
         if prompt and task_uuid: