Archived
snowy-yang
046225e38d
为什么：aria2p 内部是 requests + websocket-client 的同步实现，每个 RPC 都是一次 「同步网络 IO 藏在 to_thread 里」——线程池跑得再满也不产生真正的并发，每次轮询 还要额外付一次线程跳转。这是本项目最后一处此类残留，删掉后整个进程的网络 IO 都走同一个 aiohttp 连接池。 改动： - music_downloader/_aria2.py 整体重写：新增 _Aria2Rpc，直接向 aria2 的 JSON-RPC 2.0 端点发 getVersion / addUri / tellStatus / forceRemove / removeDownloadResult，一律走 core.http_client.request_once（不重试，与 aria2p 口径一致）；新增 Aria2RpcError 承载 HTTP 200 + error 对象的协议错误。 - _abort 逐条复刻 aria2p.remove(force=True, files=?, clean=True) 语义：终态走 removeDownloadResult；在途先 forceRemove 再清结果表；控制文件 .aria2 无条件 删除（clean=True 默认）；仅当 files 且主移除成功才删数据文件。 - get_backend / _try_start 改原生异步：asyncio.Lock 单飞 + await rpc.get_version() 探活，不再用 to_thread 包 subprocess.Popen；超时路径改 to_thread(_reap) 回收。 - 新增 Protocol _Rpc / _ProcessHandle（补 returncode 声明）——只声明本模块真正 调用的方法，测试据此用轻量替身驱动状态机，不必依赖真实 aria2 进程。 - pyproject.toml 删 aria2p 依赖并同步更新过时注释；uv lock 连带移除 8 个传递 依赖：requests / urllib3 / websocket-client / charset-normalizer / loguru / platformdirs / win32-setctime。至此全仓无任何 requests 栈。 - tests/test_aria2.py 重写为 21 项用例（_FakeRpc / _FakeProc / _LiveProc / _FakeHTTP 替身），新增终态体积守卫、_try_start 三分支（就绪重试 / 超时不就绪 杀进程 / 进程提前退出）与 JSON-RPC 信封四例。 - tests/test_downloader.py 的 get_backend 替身由同步 lambda 改为协程——调用点 已直接 await，同步替身会被 await 成 None 而报 TypeError。 验证（在 aria2p 已物理移除的环境上复核，故能真正证明无残留依赖）： - uv run ruff check . → All checks passed! - uv run pyright → 0 errors, 0 warnings, 0 informations - uv run pytest → 392 项，0 失败 / 0 error / 0 skipped（基线 382，净增 10） - data/site.db sha256 前后一致（a19f5dbf…6487），无 -wal/-shm 残留
752 lines
33 KiB
Python
752 lines
33 KiB
Python
# -*- coding: utf-8 -*-
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"""下载主类：落盘、元数据写入与交付。
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（自 music_downloader.py 拆出。）
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异步口径：整个下载链路是协程。网络走 core.http_client（进程级连接池），
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文件落盘/标签写入是阻塞 IO 与纯 Python CPU 工作，经 ``asyncio.to_thread`` 卸载；
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互斥改 asyncio 锁（见 _concurrency），取消仍由 threading.Event 承载——
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取消位由请求线程/监控线程置位，只有轮询读取，跨线程安全且无需跨循环唤醒。
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"""
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from __future__ import annotations
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import asyncio
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import os
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import re
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import threading
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from pathlib import Path
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from core.http_client import UpstreamError, UpstreamHTTPError, iter_chunks
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from core.http_client import client as _http
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from music_api import APIException, NeteaseAPI, load_cookies
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from ._aria2 import Aria2Backend, get_backend
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from ._concurrency import (
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CountingSemaphore,
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get_file_lock,
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)
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from ._http import (
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DL_CHUNK_SIZE,
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_sniff_audio_header,
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)
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from ._log import (
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logger,
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)
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from .cover import (
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fetch_cover_bytes,
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)
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from .models import (
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API_TYPE_TO_EXT,
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DownloadCanceled,
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DownloadException,
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DownloadResult,
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MusicInfo,
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_RetryFromScratch,
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)
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from .tagging import build_tags, write_tags
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# 单文件下载体积硬上限：超限即弃，防止单文件拖垮磁盘
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_MAX_DOWNLOAD_BYTES = 500 * 1024 * 1024
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# ============ 核心实现 ============
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class MusicDownloader:
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"""网易云音乐下载器
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用法:
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downloader = MusicDownloader(download_dir="downloads")
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result = await downloader.download_music_file(music_id, quality="lossless")
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"""
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def __init__(
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self,
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download_dir: str = "downloads",
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max_concurrent: int = 3,
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global_max_concurrent: int = 10,
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):
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"""
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Args:
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download_dir: 下载目录
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max_concurrent: 单个批量任务内的最大并发下载数
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global_max_concurrent: 整个服务同时下载的文件数（含标签写入）。
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所有请求共享该闸，防止大量用户同时下载导致内存/CPU 耗尽。
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"""
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self.download_dir = Path(download_dir)
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self.download_dir.mkdir(exist_ok=True)
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self.max_concurrent = max_concurrent
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self.api = NeteaseAPI()
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# 全局并发闸：所有请求共用，限制同时进行的下载数
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# （带计数，供前端实时展示排队情况）
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self._download_semaphore = CountingSemaphore(global_max_concurrent)
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# 标签写入专用闸：写标签会重写整个文件（IO 密集），
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# 与下载分离限流 —— 写满时只阻塞后来者，不占下载名额、不拖慢其它文件的传输
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cpu_count = os.cpu_count() or 2
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self._tag_semaphore = asyncio.Semaphore(max(1, min(4, cpu_count)))
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# ----------- 工具方法 -----------
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def _sanitize_filename(self, filename: str, max_bytes: int = 180) -> str:
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"""清理文件名非法字符。
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换行/回车/制表等控制字符一律剔除（否则 send_file 头部 500）；
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按 UTF-8 字节截断（Linux 文件系统 255 字节上限，中文按字符截 200 会超），
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且从 _build_file_path 传入时保证尾部 [ID 音质] 标记不被截掉。"""
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filename = re.sub(r'[\x00-\x1f\x7f]', '', filename)
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filename = re.sub(r'[<>:"/\\|?*]', '_', filename)
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filename = filename.strip(' .')
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# 按字节截断（在字符边界上回退，不产生半个字符）
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raw = filename.encode('utf-8')
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if len(raw) > max_bytes:
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cut = filename.encode('utf-8')[:max_bytes]
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# 回退到合法 UTF-8 边界
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while cut and (cut[-1] & 0xC0) == 0x80:
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cut = cut[:-1]
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filename = cut.decode('utf-8', errors='ignore').rstrip(' .')
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return filename or "unknown"
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def _determine_file_extension(
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self,
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url: str,
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content_type: str = "",
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api_type: str = "",
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) -> str:
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"""确定文件扩展名
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优先级: API 返回的 type > URL 后缀 > HTTP Content-Type > 默认 mp3
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"""
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api_type = (api_type or "").lower()
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if api_type in API_TYPE_TO_EXT:
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return API_TYPE_TO_EXT[api_type]
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url_lower = url.lower()
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if ".flac" in url_lower:
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return ".flac"
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if ".mp3" in url_lower:
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return ".mp3"
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if ".m4a" in url_lower or ".mp4" in url_lower:
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return ".m4a"
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content_type = (content_type or "").lower()
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if "flac" in content_type:
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return ".flac"
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if "mpeg" in content_type or "mp3" in content_type:
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return ".mp3"
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if "mp4" in content_type or "m4a" in content_type:
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return ".m4a"
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return ".mp3"
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@staticmethod
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def _unlink_quiet(path: Path) -> None:
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"""安静地删除文件，忽略不存在 / 权限错误"""
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try:
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path.unlink()
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except OSError:
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pass
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# ----------- 信息获取 -----------
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async def get_music_info(self, music_id: int, quality: str = "standard",
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cookies: dict[str, str] | None = None) -> MusicInfo:
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"""获取音乐详细信息（URL/详情/歌词 3 个接口并发请求，加快单曲/批量启动）"""
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try:
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cookies = cookies if cookies is not None else load_cookies()
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# 3 个接口并发请求，单曲下载/批量预取都能明显提速
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# URL/详情拿到后不再等待失败的歌词请求，已知失败不拖着等完
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url_result, detail_result, lyric_result = await asyncio.gather(
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self.api.get_song_url(music_id, quality, cookies),
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self.api.get_song_detail(music_id),
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self.api.get_lyric(music_id, cookies),
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return_exceptions=True,
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)
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if isinstance(url_result, BaseException):
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raise url_result
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if isinstance(detail_result, BaseException):
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raise detail_result
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if isinstance(lyric_result, BaseException):
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lyric_result = None # 歌词接口抖动不阻断解析/下载
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if not url_result.get("data") or not url_result["data"]:
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raise DownloadException(f"无法获取音乐ID {music_id} 的播放链接")
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# 上游 data 数组元素可能为 null（同族）
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song_data = url_result["data"][0] or {}
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download_url = song_data.get("url", "") or ""
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if not download_url:
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raise DownloadException(f"音乐ID {music_id} 无可用的下载链接")
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if not detail_result.get("songs") or not detail_result["songs"]:
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raise DownloadException(f"无法获取音乐ID {music_id} 的详细信息")
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song_detail = detail_result["songs"][0]
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# 上游可选字段可能为 null（而非缺失），一律 (x or {}) / (x or []) 容错，
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# 可选展示信息异常不再让整首有效歌曲解析失败
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lyric = ((lyric_result or {}).get("lrc") or {}).get("lyric", "") or ""
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tlyric = ((lyric_result or {}).get("tlyric") or {}).get("lyric", "") or ""
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artists = "/".join(filter(None, ((a or {}).get("name") for a in (song_detail.get("ar") or []))))
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al = song_detail.get("al") or {}
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publish_time = al.get("publishTime", 0) or 0
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publish_year = None
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if publish_time:
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import datetime
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try:
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publish_year = datetime.datetime.fromtimestamp(publish_time / 1000).year
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except (OSError, ValueError, OverflowError):
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publish_year = None
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return MusicInfo(
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id=music_id,
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name=song_detail.get("name") or "未知歌曲",
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artists=artists or "未知艺术家",
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album=al.get("name") or "未知专辑",
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pic_url=al.get("picUrl") or "",
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duration=(song_detail.get("dt") or 0) // 1000,
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track_number=song_detail.get("no", 0) or 0,
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download_url=download_url,
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file_type=(song_data.get("type") or "mp3").lower(), # null 容错
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file_size=song_data.get("size", 0) or 0,
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quality=quality,
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lyric=lyric,
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tlyric=tlyric,
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publish_year=publish_year,
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)
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except APIException as e:
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raise DownloadException(f"API调用失败: {e}") from e
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except Exception as e:
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raise DownloadException(f"获取音乐信息时发生错误: {e}") from e
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# ----------- 文件路径 -----------
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def _build_file_path(self, music_info: MusicInfo) -> Path:
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"""根据 MusicInfo 生成下载文件路径
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文件名附带歌曲 ID 与请求音质：不同歌曲同名（不同版本/重复收录）落盘互不冲突；
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同一首歌不同音质也各自独立，避免低音质文件被当作高音质交付（调包）。
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交付文件名由调用方另行决定，不受影响。
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先截断主名（按字节），再拼接 [ID 音质] 标记——标记永不丢失，
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杜绝截断后两首不同 ID 的歌落到同一路径。
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"""
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base = f"{music_info.artists} - {music_info.name}"
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tag = f" [{music_info.id} {music_info.quality}]"
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ext = self._determine_file_extension(
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music_info.download_url,
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api_type=music_info.file_type,
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)
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# 按完整路径反算文件名可用长度——旧口径只按 Linux 255 字节
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# 截断文件名，未启用 LongPathsEnabled 的 Windows 上超长歌名会在 open 时
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# OSError 白白重试 3 轮。预算 = 240 - 目录前缀 - 扩展名 - ".part"等余量；
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# 中文名 UTF-8 字节数 ≥ 字符数，按字节截断天然保守。
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# 目录过深时按比例压缩 tag 预算。注意下限保底仍可能超过 260 字节，
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# 该病理场景需由部署侧控制 downloads 目录深度来规避。
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budget = 240 - len(str(self.download_dir)) - len(ext) - 8
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if budget < 124:
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tag_budget = max(24, budget // 3)
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else:
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tag_budget = 60
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safe_base = self._sanitize_filename(base, max_bytes=max(32, budget - tag_budget))
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safe_tag = self._sanitize_filename(tag, max_bytes=tag_budget)
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return self.download_dir / f"{safe_base}{safe_tag}{ext}"
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# ----------- 下载 -----------
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async def download_music_file(
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self,
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music_id: int,
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quality: str = "standard",
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write_meta: bool = True,
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meta_fields: list[str] | None = None,
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cookies: dict[str, str] | None = None,
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retries: int = 2,
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cancel_event: threading.Event | None = None,
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music_info: MusicInfo | None = None,
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progress_cb=None,
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) -> DownloadResult:
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"""下载音乐到本地
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Args:
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music_id: 音乐ID
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quality: 音质
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write_meta: 是否写入元数据
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meta_fields: 写入字段列表，None 表示全部
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cookies: 用于获取直链/歌词的 Cookie，None 表示全局账号
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retries: 网络/写入失败时的重试次数（默认 2 次）
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cancel_event: 取消事件，置位后立即中止下载（抛 DownloadCanceled）
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music_info: 已预取的歌曲信息（跳过重复 API 调用，用于批量加速）
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progress_cb: 可选进度回调 progress_cb(written_bytes, total_bytes)。
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每写一个分块调用一次（含续传起点）；回调内部的异常会被吞掉，
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绝不影响下载主流程。调用方自行限频。
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说明:
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- 流式下载到 .part 临时文件，完整下载后再原子改名，半截文件不会被当作已下载
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- 断点续传：失败保留 .part，重试/下次下载从已写字节续传（服务器支持 Range 时）
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- per-file 锁：同名歌曲并发下载互斥，防止 .part 被交叉写入损坏
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- 连接复用：core.http_client 的进程级连接池 + keep-alive
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- 网络传输与标签写入分离限流，互不抢占对方资源
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本函数只保留编排与重试策略：缓存校验、续传起点、传输通道、完整性判定、
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元数据限流各自见对应私有方法的 docstring（此前是 205 行 / 圈复杂度 47
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的单体，任何一处改动都要通读全部步骤）。
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"""
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if music_info is None:
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music_info = await self.get_music_info(music_id, quality, cookies)
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file_path = self._build_file_path(music_info)
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part_path0 = file_path.with_name(file_path.name + ".part")
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last_error = ""
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next_wait = 0.0
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for attempt in range(retries + 1):
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# 重试退避等待在文件锁外执行——同名并发任务不再陪睡
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if next_wait > 0:
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await asyncio.sleep(next_wait)
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next_wait = 0.0
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# 重试轮次顶部的取消检查也要清理 .part（原实现在 try 外抛出会绕过清理）
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if cancel_event is not None and cancel_event.is_set():
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self._unlink_quiet(part_path0)
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raise DownloadCanceled("下载已取消")
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# part_path 是 file_path 的 .part 别名。必须在进入下载 try 之前绑定：
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# except 分支（取消/网络错误）要清理 .part，若此处未赋值，异常处理器
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# 会以 NameError 二次崩溃、掩盖原始异常
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part_path = part_path0
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# 同一目标文件的下载者串行化（不同文件之间仍然并行）
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async with get_file_lock(file_path):
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try:
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# 其它任务可能刚好完成此文件，锁内复查（命中即返回，不再下载）
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cached = await self._cached_result(file_path, music_info,
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write_meta, meta_fields)
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if cached is not None:
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return cached
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# 上次已下完但未改名的 .part：直接转正，不发起网络请求
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promoted = await self._promote_complete_part(
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part_path, file_path, music_info, write_meta, meta_fields)
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if promoted is not None:
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return promoted
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# part_path 已在文件锁外绑定为 part_path0（同一路径）
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await self._transfer(music_info, part_path,
|
||
self._resume_offset(part_path, music_info),
|
||
cancel_event, progress_cb)
|
||
|
||
# 完整性校验（已知期望大小时必须精确相等；未知期望时至少非空）
|
||
mismatch = self._size_mismatch_error(part_path, music_info)
|
||
if mismatch:
|
||
# 保留 .part 以便断点续传；下次续传从现有字节继续
|
||
last_error = mismatch
|
||
next_wait = self._backoff_wait(attempt, retries)
|
||
continue
|
||
|
||
# 完整性通过 → 嗅探 → 原子转正 → 写元数据
|
||
return await self._publish(part_path, file_path, music_info,
|
||
cancel_event, write_meta, meta_fields)
|
||
|
||
except DownloadCanceled:
|
||
# 用户明确放弃：清理半截临时文件
|
||
self._unlink_quiet(part_path)
|
||
raise
|
||
except DownloadException:
|
||
# 确定性失败（如体积超上限）不重试——原落泛型
|
||
# handler 会删残片后从 0 重拉，3 轮白拉 ~1.5GB
|
||
raise
|
||
except _RetryFromScratch:
|
||
# .part 已清理，直接进入下一轮从头下载
|
||
last_error = "续传起点失效，重新下载"
|
||
next_wait = self._backoff_wait(attempt, retries)
|
||
continue
|
||
except (UpstreamError, OSError) as e:
|
||
# 网络错误：保留 .part 支持断点续传；
|
||
# 但若任务已被取消，.part 没有任何续传价值，一并清理
|
||
if cancel_event is not None and cancel_event.is_set():
|
||
self._unlink_quiet(part_path)
|
||
raise DownloadCanceled("下载已取消") from e
|
||
last_error = f"下载请求失败: {e}"
|
||
next_wait = self._backoff_wait(attempt, retries)
|
||
continue
|
||
except Exception as e:
|
||
last_error = f"下载过程中发生错误: {e}"
|
||
next_wait = self._backoff_wait(attempt, retries)
|
||
continue
|
||
|
||
# 最后一次尝试仍失败：若任务已取消按取消收尾
|
||
if cancel_event is not None and cancel_event.is_set():
|
||
self._unlink_quiet(part_path0)
|
||
raise DownloadCanceled("下载已取消")
|
||
return DownloadResult(success=False, error_message=last_error or "下载失败")
|
||
|
||
# ----------- 下载分步实现（download_music_file 的组成件） -----------
|
||
|
||
async def _cached_result(
|
||
self,
|
||
file_path: Path,
|
||
music_info: MusicInfo,
|
||
write_meta: bool,
|
||
meta_fields: list[str] | None,
|
||
) -> DownloadResult | None:
|
||
"""锁内复查目标文件是否已是一份可用缓存；返回 None 表示需要真正下载。
|
||
|
||
缓存与本次期望不符时视为 miss 并删除重下，而不是把旧文件当本次结果交付
|
||
（跨账号音质降级 / 上游变更都会让同 ID 同音质的实际文件不同；原实现
|
||
命中即返回、从不校验尺寸）。期望未知（file_size=0）时至少拒绝 0 字节坏文件。
|
||
"""
|
||
if not file_path.exists():
|
||
return None
|
||
st_size = file_path.stat().st_size
|
||
cache_bad = ((music_info.file_size and st_size != music_info.file_size)
|
||
or (not music_info.file_size and st_size == 0))
|
||
if cache_bad:
|
||
self._unlink_quiet(file_path)
|
||
return None
|
||
# 缓存命中也尊重本次的元数据请求（重跑一次写标签，幂等）
|
||
if write_meta:
|
||
await self._write_metadata_locked(file_path, music_info, meta_fields)
|
||
return DownloadResult(
|
||
success=True,
|
||
file_path=str(file_path),
|
||
file_size=file_path.stat().st_size,
|
||
music_info=music_info,
|
||
)
|
||
|
||
async def _promote_complete_part(
|
||
self,
|
||
part_path: Path,
|
||
file_path: Path,
|
||
music_info: MusicInfo,
|
||
write_meta: bool,
|
||
meta_fields: list[str] | None,
|
||
) -> DownloadResult | None:
|
||
"""上次已下完但未改名的 .part：直接转正交付；返回 None 表示仍需下载。
|
||
|
||
尺寸要求**精确相等**——放宽为 >= 会把超尺寸残片（上游多发货/坏分片）
|
||
转正成坏文件；期望未知时不走此路（交给下载流程）。转正后立即返回，
|
||
不再发起网络请求，否则离线时会把现成的完整文件报为失败。
|
||
"""
|
||
if not part_path.exists():
|
||
return None
|
||
if not (music_info.file_size > 0
|
||
and part_path.stat().st_size == music_info.file_size):
|
||
return None
|
||
os.replace(part_path, file_path)
|
||
if write_meta:
|
||
await self._write_metadata_locked(file_path, music_info, meta_fields)
|
||
return DownloadResult(
|
||
success=True,
|
||
file_path=str(file_path),
|
||
file_size=file_path.stat().st_size,
|
||
music_info=music_info,
|
||
)
|
||
|
||
def _resume_offset(self, part_path: Path, music_info: MusicInfo) -> int:
|
||
"""断点续传起点；返回 0 表示从头下载（顺带清理没有续传价值的残片）。"""
|
||
if not part_path.exists():
|
||
return 0
|
||
existing = part_path.stat().st_size
|
||
if existing <= 0:
|
||
self._unlink_quiet(part_path) # 0 字节残片无续传价值
|
||
return 0
|
||
if music_info.file_size > 0 and existing > music_info.file_size:
|
||
# 超尺寸残片（上游多发货/坏分片）丢弃从头下——留着会被
|
||
# 「尺寸相等即转正」误交付
|
||
self._unlink_quiet(part_path)
|
||
return 0
|
||
return existing
|
||
|
||
async def _transfer(
|
||
self,
|
||
music_info: MusicInfo,
|
||
part_path: Path,
|
||
resume_from: int,
|
||
cancel_event: threading.Event | None,
|
||
progress_cb,
|
||
) -> None:
|
||
"""占全局下载名额后落盘（产物恒为 part_path），异常语义由两条通道对齐。
|
||
|
||
aria2c 可用时优先（多连接 + 原生断点续传），否则走内置 aiohttp 流式通道。
|
||
"""
|
||
# 排队用可取消等待：原阻塞式 with 使取消后仍要等全局 10 名额腾出，
|
||
# 任务卡死、退款延迟
|
||
if not await self._download_semaphore.acquire_cancellable(cancel_event, poll=0.5):
|
||
raise DownloadCanceled("下载已取消")
|
||
try:
|
||
# get_backend 首次调用要拉起 aria2c 并等 RPC 就绪（最长 8s）；
|
||
# 它已是原生异步（等待用 await asyncio.sleep 让出事件循环），直接 await
|
||
aria2_backend = await get_backend()
|
||
if aria2_backend is not None:
|
||
# aria2c 通道：多连接 + 原生断点续传
|
||
await self._fetch_via_aria2(aria2_backend, music_info, part_path,
|
||
cancel_event, progress_cb)
|
||
else:
|
||
# 内置通道：aiohttp 流式落盘 + Range 起点校验
|
||
await self._fetch_via_http(music_info, part_path, resume_from,
|
||
cancel_event, progress_cb)
|
||
finally:
|
||
# 与 acquire_cancellable 配对释放（原 with 语义）
|
||
self._download_semaphore.release()
|
||
|
||
@staticmethod
|
||
def _size_mismatch_error(part_path: Path, music_info: MusicInfo) -> str:
|
||
"""完整性判定：已知期望大小时精确相等，未知期望时至少非空。
|
||
|
||
通过返回空串；否则返回失败原因（.part 由调用方保留以供下轮续传）。
|
||
"""
|
||
actual_size = part_path.stat().st_size
|
||
if music_info.file_size > 0:
|
||
complete = (actual_size == music_info.file_size)
|
||
else:
|
||
complete = (actual_size > 0)
|
||
if complete:
|
||
return ''
|
||
return (f"下载不完整: 期望 {music_info.file_size or '未知'} 字节, "
|
||
f"实际 {actual_size} 字节")
|
||
|
||
async def _publish(
|
||
self,
|
||
part_path: Path,
|
||
file_path: Path,
|
||
music_info: MusicInfo,
|
||
cancel_event: threading.Event | None,
|
||
write_meta: bool,
|
||
meta_fields: list[str] | None,
|
||
) -> DownloadResult:
|
||
"""完整性通过后的收尾：内容嗅探 → 原子转正 → 写入元数据。
|
||
|
||
嗅探只在期望尺寸未知（"非空即通过"口径）时执行——该口径下 CDN 错误页/
|
||
风控 JSON 曾可被存成音频交付。转正走 os.replace，半截文件不会被当作已下载。
|
||
调用点必须在文件锁内（元数据也要求在锁内，其它请求才看到已完成标记的文件）。
|
||
"""
|
||
if music_info.file_size <= 0 and not _sniff_audio_header(part_path):
|
||
self._unlink_quiet(part_path)
|
||
raise DownloadException("下载内容校验失败（非音频数据）")
|
||
|
||
os.replace(part_path, file_path)
|
||
|
||
# 元数据写入移出下载闸（CPU 操作不占网络名额），
|
||
# 但仍在文件锁内执行，保证其它请求看到的是已写入标签的最终文件
|
||
if write_meta:
|
||
# 元数据段入口补取消检查点——已取消的任务不再
|
||
# 进入标签闸排队/写盘等待（有界但可达数十秒），收尾不再延迟
|
||
if cancel_event is not None and cancel_event.is_set():
|
||
raise DownloadCanceled("下载已取消")
|
||
await self._write_metadata_locked(file_path, music_info, meta_fields)
|
||
|
||
return DownloadResult(
|
||
success=True,
|
||
file_path=str(file_path),
|
||
file_size=file_path.stat().st_size,
|
||
music_info=music_info,
|
||
)
|
||
|
||
async def _write_metadata_locked(
|
||
self,
|
||
file_path: Path,
|
||
music_info: MusicInfo,
|
||
meta_fields: list[str] | None,
|
||
) -> None:
|
||
"""在标签闸内写元数据：写标签会重写整个文件（IO 密集），与下载分离
|
||
限流——写满时只阻塞后来者，不占下载名额、不拖慢其它文件的传输。"""
|
||
async with self._tag_semaphore:
|
||
await self._write_metadata(file_path, music_info, meta_fields)
|
||
|
||
@staticmethod
|
||
def _backoff_wait(attempt: int, retries: int) -> float:
|
||
"""失败后的退避秒数；已是最后一轮则不等待。锁外等待——同名并发任务不陪睡。"""
|
||
return 0.5 * (attempt + 1) if attempt < retries else 0.0
|
||
|
||
|
||
# ----------- 传输通道（二选一，产物都是 part_path） -----------
|
||
|
||
async def _fetch_via_http(
|
||
self,
|
||
music_info: MusicInfo,
|
||
part_path: Path,
|
||
resume_from: int,
|
||
cancel_event: threading.Event | None,
|
||
progress_cb,
|
||
) -> None:
|
||
"""内置流式通道：core.http_client 逐块落盘，支持 Range 断点续传。
|
||
|
||
四步：构造 Range 头 → 发请求 → 定追加/重写并校验分片起点 → 流式落盘
|
||
（含体积上限与取消）。HTTP 错误在此分类成「确定性失败」或交外层重试。
|
||
|
||
Raises:
|
||
DownloadCanceled: 取消事件置位
|
||
DownloadException: 体积超限、CDN 4xx 等确定性失败
|
||
_RetryFromScratch: 续传起点失效（残片已清，外层从头重下）
|
||
UpstreamError: 网络/5xx 等可重试失败（保留残片续传）
|
||
"""
|
||
expected_size = music_info.file_size or 0
|
||
self._safe_progress(progress_cb, resume_from, expected_size)
|
||
resp = None
|
||
try:
|
||
headers = self._range_headers(resume_from)
|
||
resp = await _http.open('GET', music_info.download_url,
|
||
headers=headers or None, timeout=60)
|
||
mode = self._resolve_write_mode(resp, resume_from, part_path)
|
||
if resp.status >= 400:
|
||
raise UpstreamHTTPError(resp.status, resp.reason or '')
|
||
await self._stream_body(resp, part_path, mode, resume_from,
|
||
expected_size, cancel_event, progress_cb)
|
||
except UpstreamHTTPError as e:
|
||
status = e.status
|
||
if status == 416:
|
||
# Range 起点无效（如 CDN 环节变化）：清除旧 part，从头重新下载
|
||
self._unlink_quiet(part_path)
|
||
raise _RetryFromScratch("Range 起点失效，已从头重新下载") from e
|
||
if self._is_deterministic_client_error(status):
|
||
self._unlink_quiet(part_path)
|
||
raise DownloadException(
|
||
f"下载失败（HTTP {status}），下载链接可能已失效") from e
|
||
raise
|
||
finally:
|
||
if resp is not None:
|
||
resp.close()
|
||
|
||
@staticmethod
|
||
def _range_headers(resume_from: int) -> dict[str, str]:
|
||
"""续传时请求「起点之后的全部字节」，否则不带头。"""
|
||
if resume_from > 0:
|
||
return {"Range": f"bytes={resume_from}-"}
|
||
return {}
|
||
|
||
def _resolve_write_mode(self, resp, resume_from: int, part_path: Path) -> str:
|
||
"""落盘方式：续传且服务器确实给了 206 才追加，否则从头重写。
|
||
|
||
服务器忽略 Range 返回 200 时若继续追加，会把整段拼在残片后面；206 还须
|
||
校验分片起点（见 _verify_content_range）。
|
||
"""
|
||
if resume_from <= 0 or resp.status != 206:
|
||
return "wb"
|
||
self._verify_content_range(resp, resume_from, part_path)
|
||
return "ab"
|
||
|
||
def _verify_content_range(self, resp, resume_from: int, part_path: Path) -> None:
|
||
"""校验 206 的分片起点；无法确认起点就清残片从头下。
|
||
|
||
起点错位的分片拼起来是坏文件——代价远大于多下一次，故与「头被中间层
|
||
剥离、解析不出起点」同口径处理。
|
||
"""
|
||
content_range = (resp.headers.get("Content-Range") or "").strip()
|
||
m = re.match(r"bytes\s+(\d+)-", content_range)
|
||
if m is not None and int(m.group(1)) == resume_from:
|
||
return
|
||
self._unlink_quiet(part_path)
|
||
if m is None:
|
||
raise _RetryFromScratch("206 响应缺少可用 Content-Range，已从头重新下载")
|
||
raise _RetryFromScratch(
|
||
f"Content-Range 起点错位（{m.group(1)} != {resume_from}），已从头重新下载")
|
||
|
||
async def _stream_body(
|
||
self,
|
||
resp,
|
||
part_path: Path,
|
||
mode: str,
|
||
resume_from: int,
|
||
expected_size: int,
|
||
cancel_event: threading.Event | None,
|
||
progress_cb,
|
||
) -> None:
|
||
"""逐块写入 part_path：取消检查 + 体积硬上限（500MB）+ 进度上报。
|
||
|
||
超限不能就地删除——Windows 无法删除仍被打开的文件，先置标志退出 with
|
||
再清理（原实现在打开中 unlink 被静默吞掉，超限残片留在磁盘上）。
|
||
"""
|
||
max_bytes = _MAX_DOWNLOAD_BYTES
|
||
written = resume_from if mode == "ab" else 0
|
||
over_limit = False
|
||
with open(part_path, mode) as f:
|
||
async for chunk in iter_chunks(resp, DL_CHUNK_SIZE):
|
||
if cancel_event is not None and cancel_event.is_set():
|
||
raise DownloadCanceled("下载已取消")
|
||
if not chunk:
|
||
continue
|
||
f.write(chunk)
|
||
written += len(chunk)
|
||
if written > max_bytes:
|
||
over_limit = True
|
||
break
|
||
self._safe_progress(progress_cb, written, expected_size)
|
||
if over_limit:
|
||
self._unlink_quiet(part_path) # 文件已关闭，清理可达
|
||
raise DownloadException(
|
||
f"文件超过大小上限 {max_bytes // (1024*1024)}MB，已中止")
|
||
|
||
@staticmethod
|
||
def _safe_progress(progress_cb, written: int, total: int) -> None:
|
||
"""上报一次进度；回调抛异常绝不影响下载主流程。"""
|
||
if progress_cb is None:
|
||
return
|
||
try:
|
||
progress_cb(written, total)
|
||
except Exception:
|
||
pass
|
||
|
||
@staticmethod
|
||
def _is_deterministic_client_error(status: int | None) -> bool:
|
||
"""确定性 4xx（403 防盗链 / 429 风控等）：对同一失效直链重试只会加剧风控、
|
||
拖慢失败返回。408 请求超时是唯一保留可重试的 4xx。
|
||
"""
|
||
return status is not None and 400 <= status < 500 and status != 408
|
||
|
||
async def _fetch_via_aria2(
|
||
self,
|
||
backend: Aria2Backend,
|
||
music_info: MusicInfo,
|
||
part_path: Path,
|
||
cancel_event: threading.Event | None,
|
||
progress_cb,
|
||
) -> None:
|
||
"""aria2c 通道：多连接加速 + 原生断点续传。
|
||
|
||
异常语义与内置通道对齐：取消抛 DownloadCanceled、体积超限抛
|
||
DownloadException（均清残片），网络类失败抛 UpstreamNetworkError
|
||
（保留残片，由外层退避重试续传）。
|
||
"""
|
||
await backend.fetch(
|
||
music_info.download_url,
|
||
part_path,
|
||
cancel_event=cancel_event,
|
||
progress_cb=progress_cb,
|
||
max_bytes=_MAX_DOWNLOAD_BYTES,
|
||
)
|
||
|
||
|
||
# ============ 元数据写入（mutagen，纯 Python） ============
|
||
# download_music_to_memory / download_batch_async / get_download_progress
|
||
# 三个方法已删除——全服务端与验证脚本零调用（CLI 遗留），且 to_memory 不接受
|
||
# cookies 参数、真被启用会有行为差异；如需内存下载/异步批量再按当前接口重写
|
||
|
||
async def _write_metadata(
|
||
self,
|
||
file_path: Path,
|
||
music_info: MusicInfo,
|
||
fields: list[str] | None = None,
|
||
) -> bool:
|
||
"""写入音频标签与封面（mutagen）；失败不影响交付，返回是否成功。
|
||
|
||
Args:
|
||
file_path: 已转正的音频文件
|
||
music_info: 歌曲信息（标题/歌手/专辑/年份/曲号/歌词/封面地址）
|
||
fields: 要写入的字段列表，None 表示全部写入
|
||
|
||
封面走共享缓存（与 ZIP 打包共用一次网络请求）；各容器的落盘细节见
|
||
tagging.py——按扩展名分派到 ID3v2.3 / Vorbis comment / iTunes ilst。
|
||
写盘是阻塞 IO + 纯 Python CPU（mutagen 全量重写文件），经 to_thread 卸载。
|
||
"""
|
||
include_cover = fields is None or "cover" in fields
|
||
cover: bytes | None = None
|
||
if include_cover and music_info.pic_url:
|
||
cover = await fetch_cover_bytes(music_info.pic_url)
|
||
if not cover:
|
||
logger.warning("封面下载失败，跳过封面写入")
|
||
return await asyncio.to_thread(
|
||
write_tags, file_path, build_tags(music_info, fields), cover)
|