diff --git a/api/core/file/models.py b/api/core/file/models.py
index aa3b5f629c..f61334e7bc 100644
--- a/api/core/file/models.py
+++ b/api/core/file/models.py
@@ -51,7 +51,7 @@ class File(BaseModel):
     # It should be set to `ToolFile.id` when `transfer_method` is `tool_file`.
     related_id: Optional[str] = None
     filename: Optional[str] = None
-    extension: Optional[str] = Field(default=None, description="File extension, should contains dot")
+    extension: Optional[str] = Field(default=None, description="File extension, should contain dot")
     mime_type: Optional[str] = None
     size: int = -1
 
diff --git a/api/core/file/upload_file_parser.py b/api/core/file/upload_file_parser.py
deleted file mode 100644
index 96b2884811..0000000000
--- a/api/core/file/upload_file_parser.py
+++ /dev/null
@@ -1,67 +0,0 @@
-import base64
-import logging
-import time
-from typing import Optional
-
-from configs import dify_config
-from constants import IMAGE_EXTENSIONS
-from core.helper.url_signer import UrlSigner
-from extensions.ext_storage import storage
-
-
-class UploadFileParser:
-    @classmethod
-    def get_image_data(cls, upload_file, force_url: bool = False) -> Optional[str]:
-        if not upload_file:
-            return None
-
-        if upload_file.extension not in IMAGE_EXTENSIONS:
-            return None
-
-        if dify_config.MULTIMODAL_SEND_FORMAT == "url" or force_url:
-            return cls.get_signed_temp_image_url(upload_file.id)
-        else:
-            # get image file base64
-            try:
-                data = storage.load(upload_file.key)
-            except FileNotFoundError:
-                logging.exception(f"File not found: {upload_file.key}")
-                return None
-
-            encoded_string = base64.b64encode(data).decode("utf-8")
-            return f"data:{upload_file.mime_type};base64,{encoded_string}"
-
-    @classmethod
-    def get_signed_temp_image_url(cls, upload_file_id) -> str:
-        """
-        get signed url from upload file
-
-        :param upload_file_id: the id of UploadFile object
-        :return:
-        """
-        base_url = dify_config.FILES_URL
-        image_preview_url = f"{base_url}/files/{upload_file_id}/image-preview"
-
-        return UrlSigner.get_signed_url(url=image_preview_url, sign_key=upload_file_id, prefix="image-preview")
-
-    @classmethod
-    def verify_image_file_signature(cls, upload_file_id: str, timestamp: str, nonce: str, sign: str) -> bool:
-        """
-        verify signature
-
-        :param upload_file_id: file id
-        :param timestamp: timestamp
-        :param nonce: nonce
-        :param sign: signature
-        :return:
-        """
-        result = UrlSigner.verify(
-            sign_key=upload_file_id, timestamp=timestamp, nonce=nonce, sign=sign, prefix="image-preview"
-        )
-
-        # verify signature
-        if not result:
-            return False
-
-        current_time = int(time.time())
-        return current_time - int(timestamp) <= dify_config.FILES_ACCESS_TIMEOUT
diff --git a/api/core/helper/lru_cache.py b/api/core/helper/lru_cache.py
deleted file mode 100644
index 81501d2e4e..0000000000
--- a/api/core/helper/lru_cache.py
+++ /dev/null
@@ -1,22 +0,0 @@
-from collections import OrderedDict
-from typing import Any
-
-
-class LRUCache:
-    def __init__(self, capacity: int):
-        self.cache: OrderedDict[Any, Any] = OrderedDict()
-        self.capacity = capacity
-
-    def get(self, key: Any) -> Any:
-        if key not in self.cache:
-            return None
-        else:
-            self.cache.move_to_end(key)  # move the key to the end of the OrderedDict
-            return self.cache[key]
-
-    def put(self, key: Any, value: Any) -> None:
-        if key in self.cache:
-            self.cache.move_to_end(key)
-        self.cache[key] = value
-        if len(self.cache) > self.capacity:
-            self.cache.popitem(last=False)  # pop the first item