From 4d697692e069de1c565aef0a0aafd328b38e25e4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E8=82=89=E6=9C=AB?= <romer@roumodeMacBook-Air.local>
Date: Tue, 14 Jul 2026 12:53:58 +0800
Subject: [PATCH] feat: burn-after-read and expiry cleaner

Co-authored-by: Cursor <cursoragent@cursor.com>
---
 backend/app/main.py             | 26 +++++++++++-
 backend/app/services/cleaner.py | 35 ++++++++++++++++
 backend/tests/test_items.py     | 72 +++++++++++++++++++++++++++++++++
 3 files changed, 131 insertions(+), 2 deletions(-)
 create mode 100644 backend/app/services/cleaner.py

diff --git a/backend/app/main.py b/backend/app/main.py
index e38dede..34f7cc3 100644
--- a/backend/app/main.py
+++ b/backend/app/main.py
@@ -1,11 +1,25 @@
+import asyncio
 from contextlib import asynccontextmanager
 
 from fastapi import FastAPI
 
 from app.api.public import router as public_router
 from app.config import settings
-from app.db import Base, engine
+from app.db import Base, SessionLocal, engine
 from app import models  # noqa: F401 — register models with Base.metadata
+from app.services import cleaner as cleaner_service
+
+
+async def _cleaner_loop() -> None:
+    while True:
+        db = SessionLocal()
+        try:
+            cleaner_service.run_once(db)
+        except Exception:
+            pass
+        finally:
+            db.close()
+        await asyncio.sleep(60)
 
 
 @asynccontextmanager
@@ -13,7 +27,15 @@ async def lifespan(_app: FastAPI):
     settings.data_dir.mkdir(parents=True, exist_ok=True)
     settings.uploads_dir.mkdir(parents=True, exist_ok=True)
     Base.metadata.create_all(bind=engine)
-    yield
+    task = asyncio.create_task(_cleaner_loop())
+    try:
+        yield
+    finally:
+        task.cancel()
+        try:
+            await task
+        except asyncio.CancelledError:
+            pass
 
 
 app = FastAPI(title="MincedPad", lifespan=lifespan)
diff --git a/backend/app/services/cleaner.py b/backend/app/services/cleaner.py
new file mode 100644
index 0000000..edaba9d
--- /dev/null
+++ b/backend/app/services/cleaner.py
@@ -0,0 +1,35 @@
+"""Periodic cleanup of expired and burned items."""
+
+from __future__ import annotations
+
+from datetime import datetime
+
+from sqlalchemy import or_, select
+from sqlalchemy.orm import Session
+
+from app.models import Item
+from app.services import items as items_service
+
+
+def run_once(db: Session, *, now: datetime | None = None) -> int:
+    """Delete expired rows (+ files) and burned rows (leftover files).
+
+    Returns the number of item rows removed.
+    """
+    now = now or datetime.utcnow()
+    rows = list(
+        db.scalars(
+            select(Item).where(
+                or_(
+                    Item.burned.is_(True),
+                    (Item.expires_at.is_not(None) & (Item.expires_at <= now)),
+                )
+            )
+        ).all()
+    )
+    for item in rows:
+        items_service.delete_item_file(item)
+        db.delete(item)
+    if rows:
+        db.commit()
+    return len(rows)
diff --git a/backend/tests/test_items.py b/backend/tests/test_items.py
index c43eba0..88a52d3 100644
--- a/backend/tests/test_items.py
+++ b/backend/tests/test_items.py
@@ -199,3 +199,75 @@ def test_banned_ip_cannot_create(client):
 
     r = client.post("/api/items", json={"body": "x"})
     assert r.status_code == 403
+
+
+def test_burn_after_read(client):
+    r = client.post(
+        "/api/items",
+        json={"body": "once", "burn_after_read": True, "ttl": "never"},
+    )
+    assert r.status_code == 200
+    slug = r.json()["slug"]
+    assert client.get(f"/api/items/{slug}").status_code == 200
+    assert client.get(f"/api/items/{slug}").status_code == 404
+
+
+def test_cleaner_removes_expired(client):
+    import app.db as db_module
+    from app.models import Item
+    from app.services import cleaner
+    from sqlalchemy import select
+
+    r = client.post("/api/items", json={"body": "old", "ttl": "never"})
+    assert r.status_code == 200
+    slug = r.json()["slug"]
+
+    db = db_module.SessionLocal()
+    try:
+        item = db.scalar(select(Item).where(Item.slug == slug))
+        assert item is not None
+        item.expires_at = datetime.utcnow() - timedelta(hours=1)
+        db.commit()
+
+        n = cleaner.run_once(db)
+        assert n >= 1
+        assert db.scalar(select(Item).where(Item.slug == slug)) is None
+    finally:
+        db.close()
+
+    assert client.get(f"/api/items/{slug}").status_code == 404
+
+
+def test_cleaner_removes_burned_leftover_files(client, monkeypatch):
+    import app.db as db_module
+    import app.api.public as public_api
+    from app.models import Item
+    from app.services import cleaner
+    from app.services import items as items_service
+    from sqlalchemy import select
+
+    monkeypatch.setattr(public_api, "_delete_file_path", lambda *_a, **_k: None)
+
+    files = {"file": ("gone.txt", b"bytes", "text/plain")}
+    r = client.post(
+        "/api/items/upload",
+        files=files,
+        data={"is_public": "true", "ttl": "never", "burn_after_read": "true"},
+    )
+    assert r.status_code == 200
+    slug = r.json()["slug"]
+    assert client.get(f"/api/items/{slug}/file").status_code == 200
+
+    db = db_module.SessionLocal()
+    try:
+        item = db.scalar(select(Item).where(Item.slug == slug))
+        assert item is not None
+        path = items_service.resolve_file_path(item)
+        assert path is not None and path.is_file()
+        assert item.burned is True
+
+        cleaner.run_once(db)
+        assert not path.exists()
+        assert db.scalar(select(Item).where(Item.slug == slug)) is None
+    finally:
+        db.close()