翻译[9]-让sshfs再次伟大于浏览器中

让sshfs再次伟大于浏览器中

• 原文地址: [https://hackmd.io/@q/sftp-over-ws]
• 原作者: qbane

---

让sftp/sshfs再次伟大

本文是一份“待办清单”，整理了在 SFTP 原始规范草案已过期、濒临被遗忘之后，可供研究与实验的协议资源。
我的愿望：让 SFTP 重新被广泛采用并焕发新生。

---

我的具体使用场景

1. 与 Web 应用通过 SFTP 通信
2. 把服务器端“基于文件系统”的程序，与操作同一目录树的 Web 客户端桥接起来
3. 把浏览器当成 SFTP 客户端

---

现代方案

websocketfs（推荐）

• 仓库：https://github.com/sagemathinc/websocketfs
• 包含两个子包
  • websocket-sftp：协议层（传输层）
  • websocketfs：FUSE 集成层
• 借助 libfuse2 的 Node 绑定，彻底摆脱 sshfs 依赖
• 遗憾：目前 JS 生态暂无 libfuse3 绑定

我正在维护一份 websocketfs 分支，专注增强 websocket-sftp 包。

---

原始方案

sftp-ws（ legacy ）

• 原始仓库：https://github.com/lukaaash/sftp-ws
• 社区轻度维护版（仅升级工具链）：https://github.com/Inveniem/sftp-ws

使用方式：需借助名为 vfs 的桥接程序

服务端示例

const SFTP = require('./lib/sftp')
const server = new SFTP.Server({port: 8888,virtualRoot: '.',readOnly: true,
})

客户端示例

npx vfs ws://localhost ./local --path PATH

• 需自行打补丁，把端口参数传给 sshfs（-p PORT）
• 底层调用 sshfs localhost:PATH -o slave，通过 WebSocket 通道通信
• 新版已把 -o slave 别名改为更包容的 passive

---

互操作性杀手锏

整个过程可逆！
只要一条反向隧道即可让 SSH “客户端” 摇身变成 SFTP 服务器：

ssh -R xxxx:localhost:yyyy

这就是 SSHFS 最迷人的地方：只要 SSH 通，就能把任意文件系统镜像到任意机器。

---

GIO / GVfs 随手挂

gio mount sftp://USER@XYZ

挂载后路径示例

/run/user/1000/gvfs/sftp:host=XYZ,user=USER/SOME_PATH/…

• 参考讨论：https://news.ycombinator.com/item?id=31813979
• macOS 上暂时无法正常工作
• GVfs 虽有文件监控机制，但大多数协议未实现

---

Green End SFTP Server

• 官网：http://www.greenend.org.uk/rjk/sftpserver/
• 仓库：https://github.com/ewxrjk/sftpserver

亮点

• 维护活跃，支持 SFTP v3‒v6 全部版本
• 附带易用的客户端脚本
• 网站上有协议版本对比、扩展提案等背景资料

“SFTP over WebSocket” 实验配方

# 1. WebSocket 转发层
websocat -b --exit-on-eof ws-l:127.0.0.1:8888 lengthprefixed:tcp:127.0.0.1:9999# 2. SFTP 服务器
gesftpserver -H 127.0.0.1 -L 9999 --debug --websocat

长度前缀帧格式对 SFTP 而言属冗余，但能跑通。

---

SSHFS 活跃分支（上游已归档）

以下排名不分先后

仓库	特色
https://github.com/rozhuk-im/sshfs	多分支补丁合集
https://github.com/deadbeefsociety/sshfs	非常活跃，含大量补丁
https://github.com/neunenak/sshfs	含 Rust 移植版
https://github.com/stevenxxiu/sshfs	仅支持 SFTP v6

2023-08-29 完成的 GitHub 全库扫描结果

---

速查链接

本人整理的参考表：https://hackmd.io/BplmLAiDSZekdat-G8-gqA

冷知识
Chromium OS 内置了 SSHFS！
如果你在较新 Chromebook 启动 Linux 子系统时看到“SSHFS is launching”，就是它。
源码：https://chromium.googlesource.com/chromiumos/overlays/chromiumos-overlay/+/main/net-fs/sshfs/

延伸阅读
Samba Wiki：〈在服务器本地编辑文件〉互操作性指南
https://wiki.samba.org/index.php/Editing_files_locally_on_server:_interoperability

个人吐槽：SMB 支持文件变更监控，SFTP/SSHFS 能否也整一个？

---

Make SFTP/SSHFS Great Again
This page is a working list of resources for studying and experimenting with the SFTP protocol after its original specification draft has expired and is in danger of being forgotten. My hope is that SFTP will once again become widely adopted and awesome.

My specific use-cases are:

Communicate with web apps over SFTP
Bridge server-side filesystem-based programs with web clients that operate on the same directory tree
Use the browser as an SFTP client
websocketfs (modern)
Check out websocketfs: https://github.com/sagemathinc/websocketfs

It provides two packages:
websocket-sftp – the protocol (transport layer)
websocketfs – FUSE integration
Uses libfuse2 bindings for Node, eliminating the need for sshfs
Sadly I cannot find any libfuse3 binding in the JS ecosystem for now…

I am now maintaining a fork of websocketfs, aiming specifically to enhance the websocket-sftp package.

sftp-ws (legacy)
The original sftp-ws, SFTP over WebSocket: https://github.com/lukaaash/sftp-ws

There is a modern fork(?) https://github.com/Inveniem/sftp-ws
(merely updates the package so that it can be built with an up-to-date toolchain)

To use it, a bridge program vfs is required:

Server:

const SFTP = require('./lib/sftp')const server = new SFTP.Server({port: 8888,virtualRoot: '.',readOnly: true,
})

Client:

npx vfs ws://localhost ./local --path PATH

Note that you need to patch the code to accept a port argument and pass it to sshfs with -p PORT.

Under the hood it invokes sshfs localhost:PATH -o slave and communicates with it over the WebSocket channel.

(The option is aliased as passive in later versions, which is more inclusive.)

The interoperability
This is reversible! You can make the SSH “client” act as an SFTP server. All you need is a reverse tunnel:

ssh -R xxxx:localhost:yyyy
I think this is the best part of SSHFS: the interoperability. You can mirror part of a filesystem to other machines as long as you have a working SSH connection.

GIO?
Well, there is gio mount sftp://USER@XYZ after which you can access files under /run/user/1000/gvfs/sftp:host=XYZ,user=USER/SOME_PATH/…
goombacloud – https://news.ycombinator.com/item?id=31813979.

The support looks promising.
Cannot make it work under macOS.
Despite GVFS having a monitor mechanism, it is not implemented for most protocols.

Green End SFTP Server
Website: http://www.greenend.org.uk/rjk/sftpserver/
Repository: https://github.com/ewxrjk/sftpserver

It is a well-maintained SFTP server with a reasonable client for ad-hoc scripting. Supports all SFTP protocol versions from v3 to v6! You can also find background, extensions, comparisons between protocol versions, and more on its website.

SFTP over WebSocket
When experimenting with “SFTP over WebSocket” (that’s another story), I find it useful to pair a patched Green End SFTP Server with a patched websocat; commands shown below:

# WS server
websocat -b --exit-on-eof ws-l:127.0.0.1:8888 lengthprefixed:tcp:127.0.0.1:9999
# SFTP server
gesftpserver -H 127.0.0.1 -L 9999 --debug --websocat

The length-prefixed message framing technique is redundant for SFTP, but it works anyway.

Active forks of SSHFS
Because the upstream repo is archived, development takes place in various forks (not sorted):

https://github.com/rozhuk-im/sshfs – several patch branches (diff)
https://github.com/deadbeefsociety/sshfs – very active, includes patches! (diff)
https://github.com/neunenak/sshfs – includes a Rust port!
https://github.com/stevenxxiu/sshfs – supports and only supports SFTP v6!
Full fork scan on GitHub, retrieved 2023/8/29:

Useful links
Reference tables organized for myself:
https://hackmd.io/BplmLAiDSZekdat-G8-gqA

Chromium OS has SSHFS inside! If you have access to a recent Chrome OS device, you may have seen text like “SSHFS is launching” during the initialization phase of its Linux subsystem.
https://chromium.googlesource.com/chromiumos/overlays/chromiumos-overlay/+/main/net-fs/sshfs/

https://wiki.samba.org/index.php/Editing_files_locally_on_server:_interoperability
— My comment: SMB has a file alteration monitor; wondering if this is doable in the SFTP/SSHFS context?