Re: [9fans] WebDAV file system

[Jim Choate <ravage@einstein.ssz.com>]

On Tue, 29 Oct 2002, John E. Barham wrote:

> Hmmm.  I guess I wasn't making myself clear.

Seemed perfectly clear to me. I was simply making a point about HTTPD
and client-server under 9P and how different it was to 'standard' OS'es.

> I want to write a native Plan 9 file system that exposes a remote WebDAV
>  server in much the same way that ftpfs makes a remote ftp server appear
>  to be part of the local fs.

Rage on. You should spend less time talking ;)

> By "stateless" I meant that HTTP creates a new TCP connection...

> I don't see how even a (hypothetical) Plan 9 browser could make HTTP
> stateful since even if you have fs access to cookies,

Who needs cookies under 9P? Nobody, that's who. There is nearly -zero-
requirement for a conventional httpd under 9P, therefore there is nearly
-zero- need for cookies. Cookies are a convention to let the -server- know
where the user has been. If there is no server per se who is going to read
those cookies? Nobody. The users client can track all that locally, it
only processes html and executes cgi scripts. The trick is the cgi, there
are two 'modes' that it can be executed in. The first is conventional
cleint side scripts. Pretty easy to impliment, the users browser simply
spawns off a process with the apropriate namespace and waits for the
results to return from the process cloud. When they do, it renders the
page for the user (again via the process cloud since it doesn't need to be
done on the users i/o processor). The other approach has to do with server
side programs. These require that the user can execute them and grab their
i/o stream, but has zero control over reading, writing, or namespace. So,
9P requires that the user be able to see the name of the program and spawn
a 'process namespace' off that the user has zero control over (and I
admit I'm a little fuzzy on exactly how to do that, right now).

Note that all of this doesn't require a cookie, only that the users
browser have a pretty conventional 'history' function. This means that 9P
is -very- cost effective from the 'server' perspective. Create it, mount
it somewhere persistent, and forget about it.

Personaly I find the twist that 9P makes to the usual client-server
approach to be truly elegent.


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    We don't see things as they are,                      ravage@ssz.com
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