>
> Despite sharing the name, SFTP is not related to FTP at all.
> It is a completely different binary protocol that transfers files
> over SSH, and SSH is not a protocol designed for public
> accessible servers to serve or receive resources.
>
But the use-case you presented is not public-accessible, it requires an Apple ID, so you have all the ingredients necessary to implement SFTP or FTPS. Which both accomplish secure, resumable uploads. The commands I use on SFTP are still mget/mput etc. which are... exactly the same as I used to use over raw FTP. Not unrelated at all.
>
> I think we should focus the topic on resumable upload support
> for HTTP. We all like HTTP protocols here and hope it can be more
> powerful and support more use cases.
>
That's why my initial reply was about extending 206. Having thought about it some more, I don't think the handle of the HTTP hammer needs modified to include a 4-in-1 screwdriver. What's next, replacing SMTP with HTTP? Out-of-scope is out-of-scope and maybe that's why WebDAV didn't catch on (sorry, Julian).
-Eric