fix(qbittorrent): handle non-200 response during login to prevent long startup waits

[airium]

Description / 描述

openlist 默认在启动时访问 8080 端口测试 qbittorrent webui 连通性.
但是如果特殊程序如 vmess websocket 占用 8080, 由于该代理协议的特点, 不会返回任何payload
openlist 尝试登录后会收到 HTTP 101 升级 ws 后会长时间阻塞等待 body, 导致 openlist 在启动半途卡住

❯ ./openlist server
INFO[2026-03-23 15:12:05] reading config file: /opt/openlist/data/config.json
INFO[2026-03-23 15:12:05] load config from env with prefix: OPENLIST_
INFO[2026-03-23 15:12:05] max buffer limit: 95MB
INFO[2026-03-23 15:12:05] mmap threshold: 4MB
INFO[2026-03-23 15:12:05] init logrus...

会卡在这里完全不动, 有时数分钟无法等到:

start HTTP server @ 0.0.0.0:5244

可以使用 curl 快速复现卡住:

❯ curl -v --header 'Referer: http://localhost:8080' --data 'username=admin&password=adminadmin' http://localhost:8080/api/v2/auth/login
* Host localhost:8080 was resolved.
* IPv6: ::1
* IPv4: 127.0.0.1
*   Trying [::1]:8080...
* Connected to localhost (::1) port 8080
> POST /api/v2/auth/login HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/8.5.0
> Accept: */*
> Referer: http://localhost:8080
> Content-Length: 34
> Content-Type: application/x-www-form-urlencoded
>
< HTTP/1.1 101 Switching Protocols
< Connection: upgrade
< Sec-Websocket-Accept: dGhlIHNhbXBsZSBub25jZQ==
< Upgrade: websocket
< Date: Mon, 23 Mar 2026 07:16:03 GMT
<

根据 qb 官方 api 文档 https://github.com/qbittorrent/qBittorrent/wiki/WebUI-API-(qBittorrent-4.1)#login, 正常登录仅会返回 HTTP 200
因此可以将非 200 的返回值全部直接视为失败, 从而避免阻塞/卡住

Motivation and Context / 背景

No related

How Has This Been Tested? / 测试

添加该patch后, 启动时qb检测环节遇到非200返回能够正常改出, 不再卡住

WARN [2026-03-23 03:34:32] /home/xxxxxx/src/OpenListTeam/OpenList/internal/bootstrap/offline_download.go:12 github.com/OpenListTeam/OpenList/v4/internal/bootstrap.InitOfflineDownloadTools() init offline download tool qBittorrent failed: failed to login into qBittorrent webui with status code: 101 Switching Protocols

Checklist / 检查清单

• I have read the CONTRIBUTING document.
  我已阅读 CONTRIBUTING 文档。
• I have formatted my code with go fmt or prettier.
  我已使用 go fmt 或 prettier 格式化提交的代码。
• I have added appropriate labels to this PR (or mentioned needed labels in the description if lacking permissions).
  我已为此 PR 添加了适当的标签（如无权限或需要的标签不存在，请在描述中说明，管理员将后续处理）。
• [] I have requested review from relevant code authors using the "Request review" feature when applicable.
  我已在适当情况下使用"Request review"功能请求相关代码作者进行审查。
• I have updated the repository accordingly (If it’s needed).
  我已相应更新了相关仓库（若适用）。
  • OpenList-Frontend #XXXX
  • OpenList-Docs #XXXX

[Copilot]

Pull request overview

This PR updates the qBittorrent WebUI login flow to fail fast on non-200 HTTP responses, preventing OpenList from blocking during startup when the target endpoint responds with unexpected protocol upgrades (e.g., HTTP 101).

Changes:

• Add an early StatusCode == 200 check in qBittorrent login to avoid reading a potentially non-terminating response body.
• Improve startup behavior by returning a clear login failure error when qBittorrent API expectations are not met.

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