feat(bilibili): 新增 BV 本地缓存，修复视频暂存目录泄漏

- 新增 CACHE_DIR(../cache/bilibili)，以 BV 号为键缓存 {BV}.mp4，命中即 FileResponse、不再调用 yt-dlp
- 未命中时下载到缓存目录内的隐藏暂存目录 .dl-XXXX，成功后 os.replace 原子落盘
- finally 中 shutil.rmtree(tmpdir)：原实现只清理 cookie 临时文件，导致每次取视频都把完整视频
  永久留在 /tmp（无上限磁盘泄漏）
- 淘汰策略：TTL 7 天未访问过期 + 总量超过 2 GiB 按 mtime 从最旧开始删除
- 新增运维接口 GET /bilibili/cache_info（缓存目录/上限/文件数/总量/剩余磁盘）
- 缓存 HIT/MISS/STORE 日志加 flush=True，实时可见

source/bilibili/bilibili.py

@@ -3,7 +3,9 @@ import sys
 import base64
 import os
 import re
+import shutil
 import tempfile
+import time
 from pathlib import Path
 
 import httpx
@@ -12,6 +14,19 @@ from aiohttp import web
 COOKIE_FILE = str(Path(__file__).parent / "cookies.txt")
 UA = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/125.0.0.0 Safari/537.36"
 
+# ---------------- 本地缓存（与 pixiv 同级：source/cache/bilibili） ----------------
+CACHE_DIR = (Path(__file__).resolve().parent / "../cache/bilibili").resolve()
+CACHE_DIR.mkdir(parents=True, exist_ok=True)
+CACHE_MAX_BYTES = 2 * 1024 ** 3      # 缓存总量上限 2 GiB
+CACHE_TTL_SECONDS = 7 * 24 * 3600    # 7 天未访问即淘汰
+VIDEO_EXTS = (".mp4", ".flv", ".mkv", ".webm")
+CONTENT_TYPES = {
+    ".mp4": "video/mp4",
+    ".flv": "video/x-flv",
+    ".mkv": "video/x-matroska",
+    ".webm": "video/webm",
+}
+
 
 def _prepare_cookie_file():
     """Convert simple name=value cookies.txt to Netscape format for yt-dlp."""
@@ -36,6 +51,65 @@ def _prepare_cookie_file():
     return tmp.name
 
 
+def _cache_file(bvid):
+    """缓存命中则返回文件路径（同时刷新 mtime 作为 LRU 依据），否则 None。"""
+    for f in CACHE_DIR.glob(f"{bvid}.*"):
+        if f.is_file() and f.suffix.lower() in VIDEO_EXTS:
+            try:
+                os.utime(f, None)
+            except OSError:
+                pass
+            return f
+    return None
+
+
+def _cache_files():
+    out = []
+    for f in CACHE_DIR.iterdir():
+        if f.is_file() and f.suffix.lower() in VIDEO_EXTS:
+            out.append(f)
+    return out
+
+
+def _cache_sweep():
+    """先按 TTL 淘汰过期文件，再按总量上限从最旧（mtime 最小）开始淘汰。"""
+    now = time.time()
+    for f in _cache_files():
+        try:
+            if now - f.stat().st_mtime > CACHE_TTL_SECONDS:
+                f.unlink()
+        except OSError:
+            pass
+
+    files = _cache_files()
+    total = 0
+    for f in files:
+        try:
+            total += f.stat().st_size
+        except OSError:
+            pass
+    if total > CACHE_MAX_BYTES:
+        for f in sorted(files, key=lambda p: p.stat().st_mtime):
+            if total <= CACHE_MAX_BYTES:
+                break
+            try:
+                size = f.stat().st_size
+                f.unlink()
+                total -= size
+            except OSError:
+                pass
+
+
+def _file_response(path, bvid):
+    return web.FileResponse(
+        path=path,
+        headers={
+            "Content-Type": CONTENT_TYPES.get(path.suffix.lower(), "application/octet-stream"),
+            "Content-Disposition": f'attachment; filename="{path.name}"',
+        },
+    )
+
+
 async def resolve_bvid(link):
     # 直接是 BV 号
     m = re.search(r"(BV[a-zA-Z0-9]{10})", link)
@@ -90,11 +164,19 @@ async def get_video(url_b64=None, bv=None):
         except ValueError as e:
             return web.json_response({"error": str(e)}, status=400)
 
+    # 1) 缓存命中：直接回文件，不再调用 yt-dlp
+    cached = _cache_file(bvid)
+    if cached:
+        print(f"[bilibili] cache HIT {bvid} -> {cached.name} ({cached.stat().st_size} B)", flush=True)
+        return _file_response(cached, bvid)
+
     cookie_tmp = _prepare_cookie_file()
     if not cookie_tmp:
         return web.json_response({"error": "missing bilibili cookie"}, status=500)
 
-    tmpdir = tempfile.mkdtemp(prefix="bilibili_")
+    print(f"[bilibili] cache MISS {bvid}, downloading...", flush=True)
+    # 2) 下载到缓存目录内的隐藏临时目录（同盘，才能原子 rename 落盘）
+    tmpdir = tempfile.mkdtemp(prefix=".dl-", dir=CACHE_DIR)
     output_template = os.path.join(tmpdir, "video.%(ext)s")
     cmd = [
         os.path.join(os.path.dirname(sys.executable), "yt-dlp"),
@@ -113,16 +195,11 @@ async def get_video(url_b64=None, bv=None):
             stderr=asyncio.subprocess.PIPE,
         )
         try:
-            stdout, stderr = await asyncio.wait_for(
-                proc.communicate(), timeout=300
-            )
+            stdout, stderr = await asyncio.wait_for(proc.communicate(), timeout=300)
         except asyncio.TimeoutError:
             proc.kill()
             await proc.wait()
             return web.json_response({"error": "download timeout"}, status=504)
-        finally:
-            if cookie_tmp and os.path.exists(cookie_tmp):
-                os.unlink(cookie_tmp)
 
         video_files = [p for p in Path(tmpdir).glob("*") if p.is_file()]
         if proc.returncode != 0 and not video_files:
@@ -136,26 +213,23 @@ async def get_video(url_b64=None, bv=None):
             return web.json_response({"error": "no output file"}, status=502)
 
         video_path = max(video_files, key=lambda p: p.stat().st_size)
-
         ext = video_path.suffix.lower()
-        content_types = {
-            ".mp4": "video/mp4",
-            ".flv": "video/x-flv",
-            ".mkv": "video/x-matroska",
-            ".webm": "video/webm",
-        }
-        content_type = content_types.get(ext, "application/octet-stream")
-
-        return web.FileResponse(
-            path=video_path,
-            headers={
-                "Content-Type": content_type,
-                "Content-Disposition": f'attachment; filename="{video_path.name}"',
-            },
-        )
+        final = CACHE_DIR / f"{bvid}{ext}"
+        try:
+            os.replace(video_path, final)          # 同盘原子落盘
+        except OSError:
+            shutil.move(str(video_path), str(final))
+        _cache_sweep()
+        print(f"[bilibili] cache STORE {bvid} -> {final.name} ({final.stat().st_size} B)", flush=True)
+        return _file_response(final, bvid)
     except Exception as e:
         print(f"[bilibili] Error: {e}")
         return web.json_response({"error": str(e)}, status=500)
+    finally:
+        # 关键修复：无论成功/失败/超时都回收临时目录（原实现会把整个视频永久留在 /tmp）
+        shutil.rmtree(tmpdir, ignore_errors=True)
+        if cookie_tmp and os.path.exists(cookie_tmp):
+            os.unlink(cookie_tmp)
 
 
 async def handle_bilibili(request):
@@ -168,8 +242,33 @@ async def handle_bilibili(request):
     return await get_video(url_b64=url_b64)
 
 
+async def handle_cache_info(request):
+    files = []
+    total = 0
+    for f in _cache_files():
+        try:
+            st = f.stat()
+        except OSError:
+            continue
+        files.append({"name": f.name, "size": st.st_size, "mtime": int(st.st_mtime)})
+        total += st.st_size
+    return web.json_response(
+        {
+            "cache_dir": str(CACHE_DIR),
+            "cache_max_bytes": CACHE_MAX_BYTES,
+            "cache_ttl_seconds": CACHE_TTL_SECONDS,
+            "count": len(files),
+            "total_bytes": total,
+            "free_bytes": shutil.disk_usage(CACHE_DIR).free,
+            "files": sorted(files, key=lambda x: -x["size"]),
+        }
+    )
+
+
 app = web.Application()
 app.router.add_get("/bilibili/get_video", handle_bilibili)
+app.router.add_get("/bilibili/cache_info", handle_cache_info)
 
 if __name__ == "__main__":
-    web.run_app(app, host="127.0.0.1", port=19990)
+    print(f"Cache directory: {CACHE_DIR}")
+    web.run_app(app, host="127.0.0.1", port=9006)