improve upload file security

backend/routes/upload.py

@@ -50,6 +50,9 @@ async def upload_file(file: UploadFile = File(...)):
     if not file.filename.endswith(('.pdf', '.txt', '.html', '.md')):
         return {"error": "Only PDF, TXT, HTML and MD files are accepted"}
     
+    # Get the file extension
+    file_extension = os.path.splitext(file.filename)[1].lower()
+    
     # Generate a session ID for this file
     session_id = str(uuid.uuid4())
     
@@ -58,8 +61,11 @@ async def upload_file(file: UploadFile = File(...)):
     uploaded_files_dir = os.path.join(session_dir, "uploaded_files")
     os.makedirs(uploaded_files_dir, exist_ok=True)
     
+    # Create standardized filename
+    standardized_filename = f"document{file_extension}"
+    
     # Create the full path to save the file
-    file_path = os.path.join(uploaded_files_dir, file.filename)
+    file_path = os.path.join(uploaded_files_dir, standardized_filename)
     
     # Sauvegarder le fichier
     with open(file_path, "wb") as buffer:
@@ -72,4 +78,4 @@ async def upload_file(file: UploadFile = File(...)):
     print(f"DEBUG UPLOAD: File uploaded with session_id: {session_id}")
     print(f"DEBUG UPLOAD: Current session_files: {session_files}")
     
-    return {"filename": file.filename, "status": "uploaded", "session_id": session_id} 
+    return {"filename": standardized_filename, "status": "uploaded", "session_id": session_id}