RE: presence of authority was Re: SFTP URI issues

["Salowey, Joe" <jsalowey%cisco.com@localhost>]

Hi Tom,

Thanks for catching this.  In the SSH URI an authority should always be
required, but the path should be empty (or perhaps ignored if it is
there). So I think that the hier-part should be:

hier-part = "//" authority ["/"]

For SFTP I would think that an authority would always be required as
well but the path could be there or empty  

hier-part =  "//" authority path-abempty 

Make sense?  

Joe 

> -----Original Message-----
> From: Tom Petch [mailto:nwnetworks%dial.pipex.com@localhost] 
> Sent: Thursday, December 29, 2005 2:20 AM
> To: Salowey, Joe; ietf-ssh%NetBSD.org@localhost
> Subject: Re: presence of authority was Re: SFTP URI issues
> 
> ----- Original Message -----
> From: "Salowey, Joe" <jsalowey%cisco.com@localhost>
> To: "Tom Petch" <nwnetworks%dial.pipex.com@localhost>; <ietf-ssh%NetBSD.org@localhost>
> Sent: Wednesday, December 28, 2005 9:25 PM
> Subject: RE: presence of authority was Re: SFTP URI issues
> 
> 
> > This ABNF is for the SSH URI which should not contain a 
> non-empty path.
> > The deviation from the 3986 path was intended to describe 
> this.  I think
> > the change is correct, but I could have missed something. 
> The "sftp" URI
> > uses the path description from 3986.
> >
> Yes, understood.  I am being opaque:-(  I was obliquely 
> referring to the
> addition of brackets in the SSH URI which, I believe, changes 
> the meaning from
> RFC3986 to mean that the ssh ABNF requires authority always 
> to be present
> whereas the URI ABNF only requires authority  to be present 
> for path-abempty,
> not for the other variants of path.
> 
> So when the ABNF for the SFTP URI says it uses the path 
> definition from RFC3986,
> I am unclear what position it takes on authority, always 
> present or not.
> 
> There is, I think, a defect in RFC3986 here, in that 
> path-abempty, which is
> allowed to start // (two solidus), is only permitted to be 
> used when authority
> is present - else the // that precedes authority could be 
> confused with the //
> that starts the path-abempty.  Where RFC3986 could be 
> defective is that
> authority is defined as, being selective,
> 
>  authority     = host
>    host          =  reg-name
>     reg-name      = *( unreserved / pct-encoded / sub-delims )
> 
> which allows authority to be zero characters, in which case 
> the // can get
> confused with // :-)
> 
> So, you asked if it was ok to start a path with // - my 
> reading of RFC3986 is
> that that is what it intends to say but does not quite do so 
> ie it is ok as long
> as authority is present and is not zero length. If the last 
> is what the ABNF for
> the SFTP URI., or for the SSH URI,  intends to say, then I 
> think this should be
> spelt out; but I am not clear what you are intending to say:-(
> 
> Tom Petch
> 
> > > -----Original Message-----
> > > From: Tom Petch [mailto:nwnetworks%dial.pipex.com@localhost]
> > > Sent: Wednesday, December 28, 2005 3:37 AM
> > > To: Salowey, Joe; ietf-ssh%NetBSD.org@localhost
> > > Subject: presence of authority was Re: SFTP URI issues
> > >
> > > Mmmm
> > >
> > > I should have added to my previous reply that I never find
> > > RFC3986 easy to
> > > understand, perhaps because it is not easy to understand:-(
> > >
> > > In RFC3986 is the following
> > > hier-part     = "//" authority path-abempty
> > >                  / path-absolute
> > >                  / path-rootless
> > >                  / path-empty
> > > which means
> > >     authority path-abempty OR
> > >     path-absolute OR
> > >     path-rootless OR
> > >     path-empty
> > > while the I-D has
> > > hier-part     =  "//" authority ( path-empty / path-abempty )
> > > which means
> > >     authority path-empty OR
> > >     authority path-abempty
> > > Is this change intended?
> > >
> > > Tom Petch
> > >
> > >
>