fix: export restorable CSV backups

backend/mvp.py

@@ -1,6 +1,7 @@
 import calendar
 import csv
 import io
+import json
 import re
 from datetime import UTC, date, datetime, time, timedelta
 from pathlib import Path
@@ -798,15 +799,21 @@ async def import_ticktick(file: UploadFile = File(...), user: User = Depends(cur
     audit(db, user.id, "import", "task", count=imported); await db.commit(); return {"imported": imported, "skipped": skipped}
 
 
-@router.get("/export")
-async def export_json(user: User = Depends(current_user), db: AsyncSession = Depends(get_db)):
+def _serialize_export_value(value):
+    if isinstance(value, UUID):
+        return str(value)
+    if isinstance(value, (date, datetime)):
+        return value.isoformat()
+    return value
+
+
+def _export_payload(folders, lists, tasks, recurrences, habits, countdowns):
     def serialize(row, fields):
-        return {f: (str(v) if isinstance((v := getattr(row, f)), UUID) else v.isoformat() if isinstance(v, (date, datetime)) else v) for f in fields}
-    folders = list((await db.scalars(select(Folder).where(Folder.user_id == user.id))).all()); lists = list((await db.scalars(select(TaskList).where(TaskList.user_id == user.id))).all()); tasks = list((await db.scalars(select(Task).where(Task.user_id == user.id))).all()); habits = list((await db.scalars(select(Habit).where(Habit.user_id == user.id))).all()); countdowns = list((await db.scalars(select(Countdown).where(Countdown.user_id == user.id))).all())
-    recurrences = list((await db.scalars(select(RecurrenceTemplate).where(RecurrenceTemplate.user_id == user.id))).all())
+        return {field: _serialize_export_value(getattr(row, field)) for field in fields}
+
     return {
         "version": 1,
-        "exported_at": utcnow(),
+        "exported_at": utcnow().isoformat(),
         "folders": [serialize(x, ["id", "name", "position", "deleted_at"]) for x in folders],
         "lists": [serialize(x, ["id", "folder_id", "name", "is_inbox", "position", "deleted_at"]) for x in lists],
         "tasks": [serialize(x, ["id", "list_id", "parent_id", "title", "description", "priority", "completed", "due_at", "due_has_time", "external_id", "deleted_at"]) for x in tasks],
@@ -816,6 +823,66 @@ async def export_json(user: User = Depends(current_user), db: AsyncSession = Dep
     }
 
 
+async def _load_export_rows(user, db):
+    folders = list((await db.scalars(select(Folder).where(Folder.user_id == user.id))).all())
+    lists = list((await db.scalars(select(TaskList).where(TaskList.user_id == user.id))).all())
+    tasks = list((await db.scalars(select(Task).where(Task.user_id == user.id))).all())
+    habits = list((await db.scalars(select(Habit).where(Habit.user_id == user.id))).all())
+    countdowns = list((await db.scalars(select(Countdown).where(Countdown.user_id == user.id))).all())
+    recurrences = list((await db.scalars(select(RecurrenceTemplate).where(RecurrenceTemplate.user_id == user.id))).all())
+    return folders, lists, tasks, recurrences, habits, countdowns
+
+
+@router.get("/export")
+async def export_json(user: User = Depends(current_user), db: AsyncSession = Depends(get_db)):
+    return _export_payload(*(await _load_export_rows(user, db)))
+
+
+@router.get("/export.csv")
+async def export_csv(user: User = Depends(current_user), db: AsyncSession = Depends(get_db)):
+    payload = _export_payload(*(await _load_export_rows(user, db)))
+    output = io.StringIO()
+    writer = csv.writer(output, lineterminator="\n")
+    writer.writerow(["entity", "data"])
+    for entity in ("folders", "lists", "tasks", "recurrences", "habits", "countdowns"):
+        for row in payload[entity]:
+            writer.writerow([entity, json.dumps(row, ensure_ascii=False, separators=(",", ":"))])
+    content = "\ufeff" + output.getvalue()
+    return Response(
+        content=content,
+        media_type="text/csv; charset=utf-8",
+        headers={"Content-Disposition": 'attachment; filename="dodo-export.csv"'},
+    )
+
+
+@router.post("/restore.csv")
+async def restore_csv(
+    file: UploadFile = File(...),
+    mode: str = Query("merge", pattern="^(merge|replace)$"),
+    user: User = Depends(current_user),
+    db: AsyncSession = Depends(get_db),
+):
+    text = (await file.read()).decode("utf-8-sig")
+    payload = {
+        "version": 1,
+        "folders": [],
+        "lists": [],
+        "tasks": [],
+        "recurrences": [],
+        "habits": [],
+        "countdowns": [],
+    }
+    try:
+        for row in csv.DictReader(io.StringIO(text)):
+            entity = row.get("entity", "")
+            if entity not in payload or entity == "version":
+                raise ValueError("unknown entity")
+            payload[entity].append(json.loads(row["data"]))
+    except (csv.Error, json.JSONDecodeError, KeyError, TypeError, ValueError) as exc:
+        raise HTTPException(422, "无效的 Dodo CSV 备份") from exc
+    return await restore_json(payload, mode, user, db)
+
+
 @router.post("/restore")
 async def restore_json(payload: dict, mode: str = Query("merge", pattern="^(merge|replace)$"), user: User = Depends(current_user), db: AsyncSession = Depends(get_db)):
     if payload.get("version") != 1: