fix(uploads): persist thread uploads canonically and fail fast on upload errors (#943)

* fix(uploads): persist thread uploads canonically and fail fast on upload errors

 - write uploads to thread-scoped storage first to guarantee agent visibility
 - sync files to sandbox virtual path only for non-local sandboxes
 - fix markdown conversion flow to operate on canonical saved files and sync converted files when needed
 - prevent silent attachment upload failures in frontend submit flow (show error + abort submit)
 - add regression tests for local vs non-local upload behavior
 - update upload docs with thread-first persistence and troubleshooting notes

* Update frontend/src/core/threads/hooks.ts

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* fix(uploads): reject "." and ".." filenames in upload sanitization (#944)

* Initial plan

* fix(uploads): reject '.' and '..' filenames in upload sanitization

Co-authored-by: WillemJiang <219644+WillemJiang@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: WillemJiang <219644+WillemJiang@users.noreply.github.com>
Co-authored-by: Willem Jiang <willem.jiang@gmail.com>

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: Copilot <198982749+Copilot@users.noreply.github.com>

backend/docs/FILE_UPLOAD.md

@@ -131,6 +131,11 @@ read_file(path="/mnt/user-data/uploads/document.md")
 - 实际存储：`backend/.deer-flow/threads/{thread_id}/user-data/uploads/document.pdf`
 - 前端访问：`/api/threads/{thread_id}/artifacts/mnt/user-data/uploads/document.pdf`（HTTP URL）
 
+上传流程采用“线程目录优先”策略：
+- 先写入 `backend/.deer-flow/threads/{thread_id}/user-data/uploads/` 作为权威存储
+- 本地沙箱（`sandbox_id=local`）直接使用线程目录内容
+- 非本地沙箱会额外同步到 `/mnt/user-data/uploads/*`，确保运行时可见
+
 ## 测试示例
 
 ### 使用 curl 测试
@@ -243,7 +248,8 @@ backend/.deer-flow/threads/
 
 1. 确认 UploadsMiddleware 已在 agent.py 中注册
 2. 检查 thread_id 是否正确
-3. 确认文件确实已上传到正确的目录
+3. 确认文件确实已上传到 `backend/.deer-flow/threads/{thread_id}/user-data/uploads/`
+4. 非本地沙箱场景下，确认上传接口没有报错（需要成功完成 sandbox 同步）
 
 ## 开发建议
 

backend/src/gateway/routers/uploads.py

@@ -94,6 +94,7 @@ async def upload_files(
         raise HTTPException(status_code=400, detail="No files provided")
 
     uploads_dir = get_uploads_dir(thread_id)
+    paths = get_paths()
     uploaded_files = []
 
     sandbox_provider = get_sandbox_provider()
@@ -107,18 +108,22 @@ async def upload_files(
         try:
             # Normalize filename to prevent path traversal
             safe_filename = Path(file.filename).name
-            if not safe_filename:
+            if not safe_filename or safe_filename in {".", ".."} or "/" in safe_filename or "\\" in safe_filename:
                 logger.warning(f"Skipping file with unsafe filename: {file.filename!r}")
                 continue
 
-            # Save the original file
-            file_path = uploads_dir / safe_filename
             content = await file.read()
+            file_path = uploads_dir / safe_filename
+            file_path.write_bytes(content)
 
             # Build relative path from backend root
-            relative_path = str(get_paths().sandbox_uploads_dir(thread_id) / safe_filename)
+            relative_path = str(paths.sandbox_uploads_dir(thread_id) / safe_filename)
             virtual_path = f"{VIRTUAL_PATH_PREFIX}/uploads/{safe_filename}"
-            sandbox.update_file(virtual_path, content)
+
+            # Keep local sandbox source of truth in thread-scoped host storage.
+            # For non-local sandboxes, also sync to virtual path for runtime visibility.
+            if sandbox_id != "local":
+                sandbox.update_file(virtual_path, content)
 
             file_info = {
                 "filename": safe_filename,
@@ -135,10 +140,15 @@ async def upload_files(
             if file_ext in CONVERTIBLE_EXTENSIONS:
                 md_path = await convert_file_to_markdown(file_path)
                 if md_path:
-                    md_relative_path = str(get_paths().sandbox_uploads_dir(thread_id) / md_path.name)
+                    md_relative_path = str(paths.sandbox_uploads_dir(thread_id) / md_path.name)
+                    md_virtual_path = f"{VIRTUAL_PATH_PREFIX}/uploads/{md_path.name}"
+
+                    if sandbox_id != "local":
+                        sandbox.update_file(md_virtual_path, md_path.read_bytes())
+
                     file_info["markdown_file"] = md_path.name
                     file_info["markdown_path"] = md_relative_path
-                    file_info["markdown_virtual_path"] = f"{VIRTUAL_PATH_PREFIX}/uploads/{md_path.name}"
+                    file_info["markdown_virtual_path"] = md_virtual_path
                     file_info["markdown_artifact_url"] = f"/api/threads/{thread_id}/artifacts/mnt/user-data/uploads/{md_path.name}"
 
             uploaded_files.append(file_info)

backend/tests/test_uploads_router.py

@@ -0,0 +1,100 @@
+import asyncio
+from io import BytesIO
+from pathlib import Path
+from unittest.mock import AsyncMock, MagicMock, patch
+
+from fastapi import UploadFile
+
+from src.gateway.routers import uploads
+
+
+def test_upload_files_writes_thread_storage_and_skips_local_sandbox_sync(tmp_path):
+    thread_uploads_dir = tmp_path / "uploads"
+    thread_uploads_dir.mkdir(parents=True)
+
+    provider = MagicMock()
+    provider.acquire.return_value = "local"
+    sandbox = MagicMock()
+    provider.get.return_value = sandbox
+
+    with (
+        patch.object(uploads, "get_uploads_dir", return_value=thread_uploads_dir),
+        patch.object(uploads, "get_sandbox_provider", return_value=provider),
+    ):
+
+        file = UploadFile(filename="notes.txt", file=BytesIO(b"hello uploads"))
+        result = asyncio.run(uploads.upload_files("thread-local", files=[file]))
+
+    assert result.success is True
+    assert len(result.files) == 1
+    assert result.files[0]["filename"] == "notes.txt"
+    assert (thread_uploads_dir / "notes.txt").read_bytes() == b"hello uploads"
+
+    sandbox.update_file.assert_not_called()
+
+
+def test_upload_files_syncs_non_local_sandbox_and_marks_markdown_file(tmp_path):
+    thread_uploads_dir = tmp_path / "uploads"
+    thread_uploads_dir.mkdir(parents=True)
+
+    provider = MagicMock()
+    provider.acquire.return_value = "aio-1"
+    sandbox = MagicMock()
+    provider.get.return_value = sandbox
+
+    async def fake_convert(file_path: Path) -> Path:
+        md_path = file_path.with_suffix(".md")
+        md_path.write_text("converted", encoding="utf-8")
+        return md_path
+
+    with (
+        patch.object(uploads, "get_uploads_dir", return_value=thread_uploads_dir),
+        patch.object(uploads, "get_sandbox_provider", return_value=provider),
+        patch.object(uploads, "convert_file_to_markdown", AsyncMock(side_effect=fake_convert)),
+    ):
+
+        file = UploadFile(filename="report.pdf", file=BytesIO(b"pdf-bytes"))
+        result = asyncio.run(uploads.upload_files("thread-aio", files=[file]))
+
+    assert result.success is True
+    assert len(result.files) == 1
+    file_info = result.files[0]
+    assert file_info["filename"] == "report.pdf"
+    assert file_info["markdown_file"] == "report.md"
+
+    assert (thread_uploads_dir / "report.pdf").read_bytes() == b"pdf-bytes"
+    assert (thread_uploads_dir / "report.md").read_text(encoding="utf-8") == "converted"
+
+    sandbox.update_file.assert_any_call("/mnt/user-data/uploads/report.pdf", b"pdf-bytes")
+    sandbox.update_file.assert_any_call("/mnt/user-data/uploads/report.md", b"converted")
+
+
+def test_upload_files_rejects_dotdot_and_dot_filenames(tmp_path):
+    thread_uploads_dir = tmp_path / "uploads"
+    thread_uploads_dir.mkdir(parents=True)
+
+    provider = MagicMock()
+    provider.acquire.return_value = "local"
+    sandbox = MagicMock()
+    provider.get.return_value = sandbox
+
+    with (
+        patch.object(uploads, "get_uploads_dir", return_value=thread_uploads_dir),
+        patch.object(uploads, "get_sandbox_provider", return_value=provider),
+    ):
+        # These filenames must be rejected outright
+        for bad_name in ["..", "."]:
+            file = UploadFile(filename=bad_name, file=BytesIO(b"data"))
+            result = asyncio.run(uploads.upload_files("thread-local", files=[file]))
+            assert result.success is True
+            assert result.files == [], f"Expected no files for unsafe filename {bad_name!r}"
+
+        # Path-traversal prefixes are stripped to the basename and accepted safely
+        file = UploadFile(filename="../etc/passwd", file=BytesIO(b"data"))
+        result = asyncio.run(uploads.upload_files("thread-local", files=[file]))
+        assert result.success is True
+        assert len(result.files) == 1
+        assert result.files[0]["filename"] == "passwd"
+
+    # Only the safely normalised file should exist
+    assert [f.name for f in thread_uploads_dir.iterdir()] == ["passwd"]

frontend/src/core/threads/hooks.ts

@@ -4,6 +4,7 @@ import type { ThreadsClient } from "@langchain/langgraph-sdk/client";
 import { useStream, type UseStream } from "@langchain/langgraph-sdk/react";
 import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
 import { useCallback } from "react";
+import { toast } from "sonner";
 
 import type { PromptInputMessage } from "@/components/ai-elements/prompt-input";
 
@@ -122,17 +123,31 @@ export function useSubmitThread({
             return null;
           });
 
-          const files = (await Promise.all(filePromises)).filter(
+          const conversionResults = await Promise.all(filePromises);
+          const files = conversionResults.filter(
             (file): file is File => file !== null,
           );
+          const failedConversions = conversionResults.length - files.length;
 
-          if (files.length > 0 && threadId) {
+          if (failedConversions > 0) {
+            throw new Error(
+              `Failed to prepare ${failedConversions} attachment(s) for upload. Please retry.`,
+            );
+          }
+
+          if (!threadId) {
+            throw new Error("Thread is not ready for file upload.");
+          }
+
+          if (files.length > 0) {
             await uploadFiles(threadId, files);
           }
         } catch (error) {
           console.error("Failed to upload files:", error);
-          // Continue with message submission even if upload fails
+          const errorMessage =
-          // You might want to show an error toast here
+            error instanceof Error ? error.message : "Failed to upload files.";
+          toast.error(errorMessage);
+          throw error;
         }
       }