- From: Williams, Stuart (HP Labs, Bristol) <skw@hp.com>
- Date: Mon, 15 Sep 2008 13:25:34 +0000
- To: John Bradley <john.bradley@wingaa.com>, "Booth, David (HP Software - Boston)" <dbooth@hp.com>
- CC: "elharo@metalab.unc.edu" <elharo@metalab.unc.edu>, "www-tag@w3.org" <www-tag@w3.org>
- Message-ID: <233101CD2D78D64E8C6691E90030E5C81B6C2D13E2@GVW1120EXC.americas.hpqcorp.net>
Hello John, > -----Original Message----- > From: www-tag-request@w3.org [mailto:www-tag-request@w3.org] > On Behalf Of John Bradley > Sent: 12 September 2008 21:42 > To: Booth, David (HP Software - Boston) > Cc: elharo@metalab.unc.edu; www-tag@w3.org > Subject: Re: [XRI] Back to XRI > > David, > > Having the meta-data at a known relative location to the > "about-a-thing" URI is more practical where we have URI that > all conform to the same rules through the proxy by say adding > $XRDS to the path or query as an example. > > It however prevents us from having a rule that all URI in a > given space all of the URI are "about things" and not things > themselves. This could be finessed if required. > > A larger problem is for XRDS-Simple if the general rule is to > add $XRDS to the path and there is no document at the > location the client needs to go back to the original URI > preform a HEAD or GET and retrieve the X-XRDS-Location header > or Link header if we standardize on that. > > A failure takes XRDS-Simple from 2 GETs to 3 GETs. > > What would be ideal is if there was some equivalent to the > Link Header for requests. > > In my GET I would like to say > LINK: > rel="http://docs.oasis-open.org/xri/2.0/specs/xri-resolution-V > 2.0.html" Hmmmm.... in RFC2068 the Link: header was defined as an entity header. HTTP GET request don't usually carry an entity body (I tried scanning RFC2616 for a definitive statement and failed). So I'd expect a link: header really only to be present on an http response message. >From a web arch pov, a selector that is not visible in the request URI to distinguish between a data reference and metadata reference is a bad thing (tm). That's only to say that distinct URI should be used to refer a thing and to metadata about that thing. That's not to say that there should be any particular way of inspecting a given URI to determine whether it is a reference to a 'thing' or metadata about a 'thing' (afterall metadata documents are 'things' too and may themselves have metadata about them). > I don't think that the ability to ask for an "information > resource" that has a relation to a "non-information resource" > is unreasonable. The link header mechanism is a way to set up a set of link relations that are reported in an http response. I think that I am open to request headers (eg. accept) having an influence on what links a server responds with. However, in general an origin server is unlikely 'understand' the 'intent' of a particular request - and so may not have a basis on which to restrict the set of links(if any) that it responds with. > I feel frustrated, in that responses have the ability if > limited, to express relationships from "non-information > resources" to information resources. > > I want to say give me the XRDS information resource for the > =jbradley "non-information resource". In your HXRI design you use extra parameters in your URI to that. I know that I have said to you that I would prefer and approach that did not have to resort to parameter, but I don't have a better suggestion. At the very least they do distinguish the URI for John Bradley from a URI for metadata about how to access services related to John Bradley (his email address, his IM channels...). HEAD, rather than GET, is perhaps a very direct way of signalling an interest in metadata for a thing, rather than the thing itself - but again would induce two round trips. <snip /> > > > Your input is appreciated. > > > Regards > John Bradley Stuart -- Hewlett-Packard Limited registered Office: Cain Road, Bracknell, Berks RG12 1HN Registered No: 690597 England
Received on Monday, 15 September 2008 13:29:06 UTC