fix: fix the incorrect file retrieval method to obtain files from S3

Refactor file reading logic to use Storage provider and pathlib for file path handling.

Signed-off-by: Shirasawa <764798966@qq.com>

Author: ShirasawaSama

pipelines/google/google_gemini.py

@@ -1358,15 +1358,20 @@ async def _fetch_file_as_base64(self, file_url: str) -> Optional[str]:
             else:
                 fid = file_url.split("/files/")[-1].split("/")[0].split("?")[0]
 
+            from pathlib import Path
             from open_webui.models.files import Files
+            from open_webui.storage.provider import Storage
 
             file_obj = Files.get_file_by_id(fid)
             if file_obj and file_obj.path:
-                async with aiofiles.open(file_obj.path, "rb") as fp:
-                    raw = await fp.read()
-                enc = base64.b64encode(raw).decode()
-                mime = file_obj.meta.get("content_type", "image/png")
-                return f"data:{mime};base64,{enc}"
+                file_path = Storage.get_file(file_obj.path)
+                file_path = Path(file_path)
+                if file_path.is_file():
+                    async with aiofiles.open(file_path, "rb") as fp:
+                        raw = await fp.read()
+                    enc = base64.b64encode(raw).decode()
+                    mime = file_obj.meta.get("content_type", "image/png")
+                    return f"data:{mime};base64,{enc}"
         except Exception as e:
             self.log.warning(f"Could not fetch file {file_url}: {e}")
         return None