W3C home > Mailing lists > Public > xml-dist-app@w3.org > December 2001

RE: Possible new issue on interpretation of relative URI actors

From: Williams, Stuart <skw@hplb.hpl.hp.com>
Date: Wed, 5 Dec 2001 17:31:32 -0000
Message-ID: <5E13A1874524D411A876006008CD059F1927DC@0-mail-1.hpl.hp.com>
To: "'Christopher Ferris'" <chris.ferris@sun.com>
Cc: Noah Mendelsohn <noah_mendelsohn@us.ibm.com>, Henrik Frystyk Nielsen <henrikn@microsoft.com>, xml-dist-app@w3.org, Doug Davis <dug@us.ibm.com>
Hi Chris,

I had a slightly more subtle read of Noah's issue, in that I thought that he
was asking where in fact two roles were being denoted by the use of a
relative URI in an actor. ie does actor="#A" imply distinct roles "#A" and
"http:/foo.org/#A" 

From Noah's message:
> > I am OK with drawing the conclusion that any node that acts in role #A 
> > must (or should, if you prefer) act in some corresponding absolute URI 
> > role as well.

The trailing "as well" is suggestive of an 'additional' role as opposed to
"#A" and http://foo/#A" being different ways to denote the same single role.

Personally I'm a same single role kind of a person myself :-)

My 0.02,

Stuart

> -----Original Message-----
> From: Christopher Ferris [mailto:chris.ferris@sun.com]
> Sent: 04 December 2001 21:47
> To: Doug Davis
> Cc: Noah Mendelsohn; Henrik Frystyk Nielsen; xml-dist-app@w3.org
> Subject: Re: Possible new issue on interpretation of relative 
> URI actors
> 
> 
> I didn't interpret it that way. What I took away from
> this is that the following are equivalent w/r/t the
> actor role identified.
> 
> <S:Envelope xmlns:S="..." xml:base="http://foo/">
>    <S:Header>
> 	<X:A S:actor="#bar" xmlns:X="...">
>    </S:Header>
>    <S:Body/>
> </S:Envelope>
> 
> <S:Envelope xmlns:S="...">
>    <S:Header>
> 	<X:A S:actor="http://foo/#bar" xmlns:X="...">
>    </S:Header>
>    <S:Body/>
> </S:Envelope>
> 
> 
> My $0.02,
> 
> Chris
> 
> Doug Davis wrote:
> 
> > Noah, are you suggesting that "http://foo/" and "http://foo/#A"
> > should be equal w.r.t. determining roles?  I don't believe
> > that are (or should be) equal.
> > -Dug
> > 
> > 
> > Noah Mendelsohn/CAM/Lotus@Lotus@w3.org on 12/04/2001 03:18:48 PM
> > 
> > Sent by:  xml-dist-app-request@w3.org
> > 
> > 
> > To:   "Henrik Frystyk Nielsen" <henrikn@microsoft.com>
> > cc:   Noah Mendelsohn/CAM/Lotus@Lotus, xml-dist-app@w3.org
> > Subject:  RE: Possible new issue on interpretation of 
> relative URI actors
> > 
> > 
> > 
> > No problem.  Although we use slightly different words, I think we are in
> > general agreement.  URI's reference resources, by definition.  I am OK
> > with drawing the conclusion that any node that acts in role #A must (or
> > should, if you prefer) act in some corresponding absolute URI role as
> > well.  A consequence of this decision is, for a given absolute AbsU, a
> > node acting in #A and #B must act as either both AbsU#A and AbsU#B or
> > neither.  I think we should call that out with at least a note.
> > 
> > 
> --------------------------------------------------------------
> ----------
> > Noah Mendelsohn                                    Voice: 
> 1-617-693-4036
> > Lotus Development Corp.                            Fax: 
> 1-617-693-8676
> > One Rogers Street
> > Cambridge, MA 02142
> > 
> --------------------------------------------------------------
> ----------
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > "Henrik Frystyk Nielsen" <henrikn@microsoft.com>
> > 12/04/2001 01:05 PM
> > 
> > 
> >         To:     <noah_mendelsohn@us.ibm.com>
> >         cc:     <Noah_Mendelsohn@lotus.com>, <xml-dist-app@w3.org>
> >         Subject:        RE: Possible new issue on interpretation of
> > relative URI actors
> > 
> > 
> > 
> > I apologize if my mail seemed a bit sharp in the language - I should
> > have eaten something first.
> > 
> > Henrik
> > 
> > 
> >>-----Original Message-----
> >>From: Henrik Frystyk Nielsen
> >>Sent: Tuesday, December 04, 2001 09:12
> >>To: 'noah_mendelsohn@us.ibm.com'
> >>Cc: 'Noah_Mendelsohn@lotus.com'; 'xml-dist-app@w3.org'
> >>Subject: RE: Possible new issue on interpretation of relative
> >>URI actors
> >>
> >>
> >>
> >>In SOAP, all we use URIs for is as identifiers. A role is
> >>identified by a URI which by definition identifies a resource.
> >>We say nothing about what the semantics or properties of that
> >>resource and I think this is very important that we don't do.
> >>
> >>When you pick a specific URI scheme (like for example HTTP),
> >>you explicitly pick a URI space with certain naming
> >>properties: whether it is hierarchical, whether it is
> >>case-sensitive, etc. etc.
> >>
> >>One might know a suggested mechanism for dereferencing a URI
> >>with a specific URI scheme may and if so then there is nothing
> >>that prevents anybody from ever dereferencing a URI but that
> >>is entirely outside the scope of SOAP.
> >>
> >>Dereferencing URIs is all about trust - I may trust DNS in
> >>order to do so or I may trust somebody else to dereference it.
> >>As such I don't agree that URI semantics is dangerous in
> >>either of the cases you mention: it is a question of how I
> >>establish trust in determining whether a Node can act in the
> >>role that it claims it can.
> >>
> >>Henrik Frystyk Nielsen
> >>mailto:henrikn@microsoft.com
> >>
> >>
> >>>-----Original Message-----
> >>>From: noah_mendelsohn@us.ibm.com 
> [mailto:noah_mendelsohn@us.ibm.com]
> >>>Sent: Tuesday, December 04, 2001 08:07
> >>>To: Henrik Frystyk Nielsen
> >>>Cc: Noah_Mendelsohn@lotus.com; xml-dist-app@w3.org
> >>>Subject: RE: Possible new issue on interpretation of relative
> >>>URI actors
> >>>
> >>>
> >>>The question is not so much about establishing a base, it is about
> >>>clarifying the responsibilities of a node in assuming a role.
> >>>
> >>>We have said nothing to indicate that a role is a web
> >>>resource, or that it
> >>>is the resource named by the actor URI.  For example, we do
> >>>
> >>nothing to
> >>
> >>>preclude naming a role as the name of some other resource. 
>  Remember,
> >>>there may be a large number of intermediaries, possibly in 
> different
> >>>organizations that might want to assume a role like:
> >>>
> >>>       http://example.org/cachemanagers
> >>>
> >>>Any resource referenced by the URI is not general at any of the
> >>>intermediaries assuming the role, and it's almost surely not
> >>>one accessed
> >>>via http or that follows the rules for the HTTP scheme.  In
> >>>that respect,
> >>>one could argue that following the other rules for resources
> >>>is dangerous
> >>>as much as helpful.
> >>>
> >>>On the other hand, you might make the case that this is
> >>>talking about some
> >>>other resource, but that the assumed role itself is not the
> >>>resource.  In
> >>>other words, there's at least in principle a resource,
> >>>probably at some
> >>>nth+1st location, and the actor attribute is referring to that
> >>>resource.
> >>>In that case, I can see why we should follow the usual URI
> >>>rules.  I think
> >>>that's about where you and I would find common ground.
> >>>
> >>>In any case, I see it as subtle enough that we should indeed
> >>>say something
> >>>brief and clear about what's intended.  In other words, to say
> >>>that roles
> >>>are indeed web resources (from which follows everything I
> >>>think you want
> >>>wrt/ naming).  I'm OK with that.
> >>>
> >>>---------------------------------------------------------------
> >>>---------
> >>>Noah Mendelsohn                                    Voice:
> >>>1-617-693-4036
> >>>Lotus Development Corp.                            Fax: 
> 1-617-693-8676
> >>>One Rogers Street
> >>>Cambridge, MA 02142
> >>>---------------------------------------------------------------
> >>>---------
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>"Henrik Frystyk Nielsen" <henrikn@microsoft.com>
> >>>12/04/01 10:54 AM
> >>>
> >>>
> >>>       To:     <Noah_Mendelsohn@lotus.com>, <xml-dist-app@w3.org>
> >>>       cc:
> >>>       Subject:        RE: Possible new issue on
> >>>interpretation of relative URI actors
> >>>
> >>>
> >>>Please have a look at the proposed text for handling xml base
> >>>which already discusses the question of how to establish a
> >>>base URI for a message and how to deal with URIs in general.
> >>>Given that we already have an issue for xml base I am
> >>>wondering whether we need another issue.
> >>>
> >>>Henrik Frystyk Nielsen
> >>>mailto:henrikn@microsoft.com
> >>>
> >>>[1] 
http://lists.w3.org/Archives/Public/xml-dist-app/2001Dec/0005.html
>>>
>>>
>>>>In private discussion, Henrik and I tripped over the question of a
>>>>relative URI used as an actor.  If a block has:
>>>>
>>>>       Actor="#A"
>>>>
>>>>or
>>>>
>>>>       Actor="A"
>>>>
>>>>and if a node decides to act in that role, is there necessarily some
>>>>other absolute URI in which role it needs to act?  I had assumed
>>>>
>>>"no", but I
>>>
>>>>think Henrik had assumed "yes", and he further believes that
>>>>no changes to
>>>>the SOAP spec are needed, as this is implicit in the web and URI
>>>>architecture and the definition of a relative URI.
>>>>
>>>>I would prefer to at least be a bit clearer in the spec, say a bit
>>>>more about what the base URI for a message might be, etc.
>>>>Presumably the base
>>>>URI must be stable through message processing, so if you no
>>>>how to make #A
>>>>absolute, then #B must follow from that and be handled consistently?
>>>>
>>>>All of this bears some relation to the dreaded Namespace
>>>>
>>issue (is it
>>
>>>>a string or a real URI) but at least in this case nobody is
>>>>
>>>proposing to
>>>
>>>>actually retrieve a resource in most cases.
>>>>
>>>>Anyway, I recommend we open an issue.  Thanks.
>>>>
>>>
>>>
>>>
> 
> 
> 
> 
> 
Received on Wednesday, 5 December 2001 12:32:10 UTC

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