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Re: Mount a tar file? (gnome VFS vs. URI syntax)

From: Dan Connolly <connolly@w3.org>
Date: 16 Aug 2002 11:52:59 -0500
To: Norman Walsh <ndw@nwalsh.com>
Cc: Dan Connolly <connolly@w3.org>, www-archive@w3.org
Message-Id: <1029516780.17704.2522.camel@dirk>

+cc www-archive

I considered copying www-archive before, but decided against
it. Now I've found something reall web-related. I presume
you don't mind.

[[
 Unlike normal Internet URIs, though, GNOME VFS allows stacking of
access methods. For example, assume you want to read a file which is
stored in a .tar file. In that case, you want to be able to open the
parent .tar file, extract the file you want, and read it. In practice,
you need a tar file access method that is able to extract a file from a
.tar file, and you also need an access method to access the .tar file
itself.

This means that you want to stack the tar access method "on top" of
another generic access method to read the .tar file itself.

Stacking in GNOME VFS is achieved by using the # character, followed by
the name of the next access method. For example, if the .tar is on a
local file, you could use the following URI to combine the "tar" access
method with the "file" one:
file:/path/to/file.tar#tar/path/to/contained/file

If the .tar was on an HTTP site for which authentication is required,
you would use a URI like the following:

 http://user:password@some.host.net/path/to/
file.tar#tar/path/to/contained/file 
]]]
	-- http://www.ximian.com/devzone/tech/gnome-vfs.html

Ouch! Composition should go the other way, no?
	tar:/file%3A%2Fpath%2Fto%2Ffile/path/to/contained/file

or even:
	http://gnome.org/untar-svc?f=file%3A%2Fpath%2Fto%2Ffile;p=path/to/contained/file

with special knowledge in gnome-smart clients that replies from
gnome.org/untar-svc can be computed locally.



On Fri, 2002-08-16 at 11:38, Dan Connolly wrote:
> On Fri, 2002-08-16 at 10:09, Norman Walsh wrote:
> > Neither googling nor 'apt-cache search' turned up the 'mount a tar
> > file as a filesystem' module that you mentioned in Montreal. Did you
> > ever track it down?
> 
> Not yet... hmm... googling for 'userfs' turns up some
> familiar stuff...
> 
> "I abandoned it in 1996 or so"
> Last updated:  31 Jan 2000 
> http://www.goop.org/~jeremy/userfs/
> 
> Feb 2000
> http://www.penguin.cz/~jim/userfs/
> 
> ...
> 
> 
> Aha... from the README from
> http://www.penguin.cz/~jim/userfs/userfs-0.9.7-pre3.tar.gz
> 
> "Arcfs was  written by David Gymer.  It allows you to mount a
>      compressed tar file  as  a  read-only  filesystem,  and
>      inspect  it  with  normal tools.  It's pretty neat, but
>      not recommended for heavy "production" use, or for very
>      large files."
> 
> I haven't tried it out, though.
> 
> 
> > 
> >                                         Be seeing you,
> >                                           norm
> > 
> > -- 
> > Norman Walsh <ndw@nwalsh.com> | certain: adj., insufficiently analyzed
> > http://nwalsh.com/            | 
> -- 
> Dan Connolly, W3C http://www.w3.org/People/Connolly/

-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Friday, 16 August 2002 12:52:08 GMT

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