Archived
snowy-yang
9df0028195
迁移端点：
- POST /api/v1/download（单曲：file 后台任务 / json 同步交付+结算）
- POST /api/v1/download/batch_zip（按去重歌曲数计费）
- POST /api/v1/podcast/download、/podcast/download/batch_zip
- 新增 web/billing.py（预扣+开账同事务 / 只退 open 行 / rename 承接）
与 web/tasks_registry.py（任务登记/容量闸/账本撞名重试，与 main 同口径）
- worker 仍复用 main 既有实现（无 flask 依赖），账本与交付语义不变
修复我引入的真实缺陷：
- download 参数校验分支（ID/音质/格式非法）漏退款 → 预扣泄漏。改为统一 _fail() 退款
- web/routers/{auth,register}.py 在导入期绑定 deps.secret_key，导致 patch web.deps.secret_key
无效、且测试顺序相关。改为调用期 deps.secret_key() 解析
测试：tests/test_download_billing.py 7 项沙箱用例如实断言账本守恒
（预扣必退、无 open 行残留、次数不足不建任务）；
全套 pytest 69/69（顺序无关）；ruff All checks passed；pyright 0 errors；奇偶 36/36。
108 lines
4.1 KiB
Python
108 lines
4.1 KiB
Python
# -*- coding: utf-8 -*-
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"""FastAPI 计费依赖（账本预扣/退款），与 Flask login_required 同口径。
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Flask 版 login_required 用 flask.g 暂存请求级账本键；FastAPI 无 g，改用
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「依赖返回值携带 ledger_key + 路由内显式退款」的方式，语义完全一致：
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- 预扣与开账同事务：auth_system.reserve_and_open（A2/B8）
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- 失败退款：只退「仍 open 的账本行」（与装饰器 _refund_open 同口径，杜绝双退）
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- 任务接手：auth_system.ledger_rename 把请求级行改挂 task_id（worker 结算唯一入口）
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金额相关逻辑一律走 auth_system 既有函数，本模块不新造账务语义。
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"""
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import asyncio
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import logging
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import secrets
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from collections.abc import Callable
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from dataclasses import dataclass
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import auth_system
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from web.deps import SiteUser
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from web.errors import AppError
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logger = logging.getLogger('web.billing')
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@dataclass
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class Billing:
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"""一次请求的计费上下文。"""
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user: SiteUser
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ledger_key: str | None # 请求级账本键（unlimited 用户为 None）
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need: int # 本次预扣次数（free 路径为 0）
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free: bool
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async def refund_open(self, reason: str = 'rejected') -> None:
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"""仅对仍 open 的账本行全额退款（被 rename/结算过则跳过）。"""
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key = self.ledger_key
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if not key:
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return
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def _do() -> None:
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try:
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row = auth_system.ledger_get(key)
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if row and row['status'] == 'open':
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auth_system.ledger_settle(key, 0, reason)
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except Exception:
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pass
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await asyncio.to_thread(_do)
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async def settle(self, delivered: int, status: str = 'delivered') -> None:
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"""交付结算（json 模式等无 task_id 的场景）。"""
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key = self.ledger_key
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if not key:
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return
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try:
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await asyncio.to_thread(auth_system.ledger_settle, key, delivered, status)
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except Exception as e:
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logger.error('账本结算失败（重启对账兜底）: %s %s', key, e)
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async def rename_to(self, task_id: str) -> bool:
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"""把请求级账本行改挂 task_id（任务接手账目）。无请求级行时开 reserved=0 的账。"""
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if not self.ledger_key:
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await asyncio.to_thread(auth_system.ledger_open, task_id, self.user.id, 0)
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return True
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return await asyncio.to_thread(auth_system.ledger_rename, self.ledger_key, task_id)
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async def require_billing(
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user: SiteUser | None,
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*,
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action: str = '',
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free: bool = False,
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cost: Callable[[], int] | None = None,
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ip: str = '-',
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) -> Billing:
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"""登录 + 预扣闸（对应 Flask login_required）。
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free=True：仅要求登录，不扣次数（解析/试听类）。
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cost: 预扣次数计算（下载类：单曲 1 / 批量按去重后歌曲数）。
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"""
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if user is None:
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raise AppError('请先登录后再使用解析功能', 401, error_code='unauthorized')
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fresh = await asyncio.to_thread(auth_system.get_user_by_id, user.id)
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if fresh is None:
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raise AppError('登录已失效，请重新登录', 401, error_code='unauthorized')
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credits = int(fresh['duration_seconds'] or 0)
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unlimited = fresh['role'] == 'admin' or credits == -1
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if free or unlimited:
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return Billing(user=user, ledger_key=None, need=0, free=free)
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need = 1
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if cost is not None:
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try:
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need = max(1, int(cost()))
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except Exception:
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need = 1
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key = 'req-' + secrets.token_hex(8)
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remaining = await asyncio.to_thread(auth_system.reserve_and_open, fresh['id'], need, key)
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if remaining is None:
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await asyncio.to_thread(auth_system.add_log, 'fail', fresh['username'], ip,
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action or '下载', f'剩余次数不足（本次需 {need} 次）')
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raise AppError(f'下载次数已用尽（本次需 {need} 次，当前 {credits} 次），'
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'请充值卡密后继续下载', 401, error_code='expired')
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return Billing(user=user, ledger_key=key, need=need, free=False)
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