Fwd: Re: Fwd: Re: A common VFS and a Common conf-system [Part II]

[gtg990h at mail.gatech.edu]

Quoting Dave Cridland <dave at cridland.net>:

> It might do, just about, with HTTP URLs, which map *fairly* closely into
> filenames, files, and directories, although far from completely.

<excellent points clipped because I simply don't disagree>

> I think we could reasonably expect ftp to be able to "Just work" like this,
> as well as http - as long as that http scheme URL resolved to WebDAV, and we
> weren't doing anything too weird.
>
> Much more than that, and we're starting to expect too much.

There is no reason to expect more than what can be represented via POSIX +
xattrs. I think you can do quite a lot with that combo, but you clearly can't do
everything. That's okay, because you don't have to represent everything as POSIX
(or Win32, or whatever the host OS is). If the user cannot be reasonably
expected to want to use CLI tools on files behind a given protocol, then the
D-VFS daemon can just implement that protocol itself. The nice thing is that the
protocols on which the user might want to use existing tools are correlated with
those that lend themselves to being represented using existing file APIs.

> But yet, if I give my image viewer the IMAP URL pointing to that photo
> someone just sent me, I can clearly expect the image viewer to be capable of
> using it. Do I care that I can't use "cp" on it?

Exactly. But similarly, if somebody links me to a TeX file on a ftp drive, I
*do* expect to be able to run pdftex on it.

> Having said all this, a WebDAV filesystem at OS level would be great. FTP
> likewise. Same goes for many others, I'm sure, but not all those which
> strikes me as reasonable and desirable to have in D-VFS - and I'm not sure
> that D-VFS should always use OS facilities even when they exist.

I would consider the following list desirable to have in D-VFS: local, webdav,
ssh, samba, ftp, nfs, and similar ones like gmailfs. For those filesystems,
native services often exist, and it would be nice if D-VFS could use those
services.

I should not that I'm not saying that "D-VFS shouldn't use URIs", rather that
"URIs shouldn't be mandatory". This seems obvious, because you still want to
support names of the form "/home/me/document.txt" for file://, but that needn't
be a special case as it is in KIO and gnome-vfs. Namespaces only need to be
unified for things that the user considers to be files. That means it would be
nice to extend native pathnames to filesystems (ssh, ftp, etc), that the user
could reasonably be expected to consider as containing "files".
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