- From: John Bradley <john.bradley@wingaa.com>
- Date: Fri, 11 Jul 2008 21:51:02 -0700
- To: "Booth, David (HP Software - Boston)" <dbooth@hp.com>
- Cc: "Schleiff, Marty" <marty.schleiff@boeing.com>, "Ray Denenberg, Library of Congress" <rden@loc.gov>, "www-tag@w3.org" <www-tag@w3.org>
- Message-Id: <1DFFB1E4-B1E8-4881-97C3-9BF6F6833BCB@wingaa.com>
No problem David. Marty and I discussed it and thought it was probably a typo. I took it as intended. Thanks. John Bradley =jbradley On 11-Jul-08, at 8:57 PM, Booth, David (HP Software - Boston) wrote: > > Oops! I was just informed of a typo below that may have caused > some confusion . . . > >> From: David Booth >> >> Marty, >> >> I think XRIs have a major adoption problem. Their special >> properties are only useful to the extent that machines can >> recognize them and invoke their special semantics. And >> people are not jumping all over themselves to implement new >> URI schemes in their software. >> >> On the other hand, HTTP is ubiquitous. This is why I believe >> you will have significantly greater success piggybacking the >> XRI ideas on top of HTTP URIs, rather than inventing an new >> URI scheme. >> >> I see that the XRI 2.0 spec already defines lossless >> transformations to and from IRIs (and hence URIs): >> http://www.oasis-open.org/committees/download.php/15376/xri-sy >> ntax-V2.0-cs.html#_Converting_XRIs_to_URIs >> http://www.oasis-open.org/committees/download.php/15376/xri-sy >> ntax-V2.0-cs.html#_Toc117301857 >> so presumably an absolute XRI reference and its corresponding >> absolute URI reference could be considered semantically >> equivalent. I notice that such a URI reference always starts >> with the string "xri:", so presumably that string is how >> XRI-aware software would recognize that the URI is a >> URI-encoded XRI, and interpret its meaning as defined in the >> XRI spec. Surely there is nothing magic about that >> particular string: if the XRI spec had instead decided on >> some other arbitrary URI-conformant string such as >> "fribblejam:", and written the specs accordingly, XRIs would >> work just as well. >> >> Suppose the OASIS XRI technical committee (TC) were to decide >> to make XRIs more web friendly and lower the barrier to their >> adoption by writing a second "HTTP-XRI" spec that bases XRI's >> on http URIs roughly as follows. >> >> 1. The new HTTP-XRI spec is written to require the string >> "http://purl.org/xri/" at the beginning of an HTTP XRI, >> instead of starting with "xri:". Aside from this simple >> syntactic difference, the structure and semantics are defined >> to be *exactly* the same as for an existing URI-encoded XRI. >> (Okay, I will admit that some additional %-escaping might be >> needed also -- I haven't checked the syntax rules in enough >> detail to know -- but surely that is a technical detail that >> could be worked out, and does not significantly affect the >> point of this example.) >> >> 2. The TC registers the http://purl.org/xri/ subspace of >> purl.org's URI space and sets up a corresponding partial >> redirect so that when a HTTP XRI such as >> http://purl.org/xri/@boeing.com/(@example%2Fabc%252Fd%2Fef) >> is dereferenced in a browser, some useful information is >> returned, perhaps along the lines of: >> >> - General marketing info about HTTP-XRIs, what they >> mean, how great they are and how to adopt them; >> >> - Specific info about >> http://purl.org/xri/@boeing.com/(@example%2Fabc%252Fd%2Fef), >> perhaps by forwarding the request to a boeing.com server; and/or >> >> - Pointers to HTTP-XRI plug-ins or toolkits, to help >> bootstrap the adoption of XRI-aware software. >> >> Some observations: >> >> - HTTP-XRI-aware software would merely look for >> "http://http-xri.org?xri:" at the beginning of a URI instead > ^^^^^^^^^^^^^^^^^^^^^^^^ > > The above should have said "http://purl.org/xri/". > >> of looking for "xri:", and thereafter apply the *exact* same >> processing as it would for URI-encoded XRIs, since HTTP XRIs >> would have the *exact* same semantics. >> >> - Non-HTTP-XRI-aware software would not know about the >> special semantics of these URIs (just as non-XRI-aware >> software would not know about the special semantics of XRIs), >> so it would not be any worse off than for the XRI case. >> However, the software *might* still be able to retrieve >> useful information by dereferencing the URI that it could >> present to the user, which could not be done in the XRI case. >> >> - Software that is only *partially* XRI-aware might not have >> the ability to do XRI resolution -- HTTP resolution is >> ubiquitous, but XRI resolution clearly is not -- *but* it may >> still know a little about XRIs and may still be able to make >> use of some of the information returned by dereferencing the >> HTTP XRI, which also could not be done for the XRI case. >> >> In other words, for the most part, HTTP-XRIs would have >> virtually the same benefits as existing XRIs, plus they would >> have additional advantages: >> >> - they would be more web friendly (following good web >> architectural principles of not creating new URI schemes); and >> >> - being potentially dereferenceable with HTTP, they could >> have a significantly lower barrier to adoption as compared >> with existing XRIs. >> >> Of course, as with anything, there is a down side: >> >> - The URIs would be a little longer. >> >> - A person looking at an HTTP XRI who is not familiar with >> XRIs may not immediately realize that it has special XRI >> semantics. But being potentially dereferenceable, HTTP XRIs >> could give them an easy way to find out. >> >> - Dereferencing by non-XRI-aware software would depend on >> the stability of purl.org, and there is no absolute guarantee >> that purl.org will continue to exist and be supported years >> from now. On the other hand, there is no guarantee that XRI >> resolution software will continue to be supported years from >> now either. And if I were deciding where to place my bet, >> I'd say it is *substantially* more likely that purl.org will >> continue to be supported years from now than that XRI >> resolution software will continue to be supported, but of >> course others may think differently. >> >> My question: what would you think of the pros/cons of such an >> approach? >> >> >> >> David Booth, Ph.D. >> HP Software >> +1 617 629 8881 office | dbooth@hp.com >> http://www.hp.com/go/software >> >> Statements made herein represent the views of the author and >> do not necessarily represent the official views of HP unless >> explicitly so stated. >
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