W3C home > Mailing lists > Public > uri@w3.org > September 2004

FTP URIs - time to document the way browsers really behave?

From: Alun Jones <alunj@microsoft.com>
Date: Tue, 28 Sep 2004 15:18:45 -0700
Message-ID: <0966E90CB313084DA7A9C55799FDEFD202C46CCA@RED-MSG-50.redmond.corp.microsoft.com>
To: <uri@w3c.org>

Now that RFC 1738 is being "Historicalised", and the individual
protocols split out into their separate documents, is it appropriate to
start documenting the way in which FTP URIs are _actually_ applied in
the real world?

As I remember it (this is going back some way, and I'm not associated
with browser development, so it's very much an "outsider's view"),
Mosaic used a "liburl" that misunderstood the FTP URI spec from RFC
1738, and everyone copied Mosaic's behaviour (either directly, or by
observing).  As a result we have the following situation:

ftp://<userinfo>:<host>/path1/.../pathN is read as "log on to <host>
with credentials from <userinfo>, and either CWD to /path1/.../pathN, or
RETR /path1/.../pathN".

Now, the RFC 1738 rule says you should log on to <host> as <userinfo>,
and enter separate CWD commands for each pathM element from 1 to N, with
the possibility of issuing a RETR on pathN if the CWD fails - but notice
that this usually has the same result as CWD path1/.../pathN, or RETR
path1/.../pathN.

Yes, that's slightly different - the paths in the first case are all
absolute, those in the second case are all relative.

For most real-world uses, this is the same thing, because FTP URLs
default to anonymous access, and the anonymous user is generally locked
into what many of you know as a "chroot jail".  In such a situation,
relative and absolute are the same.  This situation went largely
unnoticed, presumably until it was too late to make a change to the
browsers' behaviour to conform to RFC 1738.

So now we have the situation that URLs don't work the way they're
documented to - and coincidentally, a chance to change the documentation
to represent a reality that has proved remarkably resistant to efforts
to bring it back in line with the documentation.

Is it possible to address this in the FTP URI document?

Alun.
~~~~
-- 
I am the 'F' in "IIS".
Received on Tuesday, 28 September 2004 22:20:46 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Thursday, 13 January 2011 12:15:34 GMT