Re: [Locators] Re: While it is still fresh in our minds: '!' is not just a funny fragment identifier...

Looks like EPUB CFI…
Luc


De : Ivan Herman <ivan@w3.org<mailto:ivan@w3.org>>
Date : mardi 22 décembre 2015 09:34
À : AUDRAIN LUC AUDRAIN LUC <laudrain@hachette-livre.fr<mailto:laudrain@hachette-livre.fr>>
Cc : Shane McCarron <shane@aptest.com<mailto:shane@aptest.com>>, Leonard Rosenthol <lrosenth@adobe.com<mailto:lrosenth@adobe.com>>, Romain Deltour <rdeltour@gmail.com<mailto:rdeltour@gmail.com>>, Bill Kasdorf <bkasdorf@apexcovantage.com<mailto:bkasdorf@apexcovantage.com>>, Tzviya Siegman <tsiegman@wiley.com<mailto:tsiegman@wiley.com>>, W3C Digital Publishing IG <public-digipub-ig@w3.org<mailto:public-digipub-ig@w3.org>>
Objet : [Locators] Re: While it is still fresh in our minds: '!' is not just a funny fragment identifier...


On 22 Dec 2015, at 09:22, AUDRAIN LUC <LAUDRAIN@hachette-livre.fr<mailto:LAUDRAIN@hachette-livre.fr>> wrote:

Sorry, perhaps I am not at the same level of abstraction.
And yes, it may be certainly a question of server’s trick.

But from a resource producer point of view, if "http://www.example.org/A!B and http://www.example.org/A are two completely different resources", is B a sub-resource of A?

By default there is nothing that says that as far as the HTTP protocol is concerned.


 *   If yes, « in A¡B, B is a sub-resource of A », then resource producers have to build « two completely different resources » for a commun content B,
 *   If no, « in A¡B, B is not a sub-resource of A », what does A¡B means a locator for B, why not use http://www.example.org/B?

Good question. And to make it clear: I did not propose the usage of the '!' character, it is just mentioned as a possible avenue. I believe it was used in a very restricted manner (and not generally):

• http://www.example.org/A is the URL yielding the PWP manifest (or something similar)
• http://www.example.org/A!B was to access a resource within the PWP (but that must either be aided by the server, or the client has to have some built in logic to manage that URI instead of issuing a direct HTTP GET>

I seem to remember that Readium uses this trick in its Service Worker experimentation.

Ivan


Luc

De : Ivan Herman <ivan@w3.org<mailto:ivan@w3.org>>
Date : mardi 22 décembre 2015 09:03
À : AUDRAIN LUC AUDRAIN LUC <laudrain@hachette-livre.fr<mailto:laudrain@hachette-livre.fr>>
Cc : Shane McCarron <shane@aptest.com<mailto:shane@aptest.com>>, Leonard Rosenthol <lrosenth@adobe.com<mailto:lrosenth@adobe.com>>, Romain Deltour <rdeltour@gmail.com<mailto:rdeltour@gmail.com>>, Bill Kasdorf <bkasdorf@apexcovantage.com<mailto:bkasdorf@apexcovantage.com>>, Tzviya Siegman <tsiegman@wiley.com<mailto:tsiegman@wiley.com>>, W3C Digital Publishing IG <public-digipub-ig@w3.org<mailto:public-digipub-ig@w3.org>>
Objet : Re: While it is still fresh in our minds: '!' is not just a funny fragment identifier...


On 22 Dec 2015, at 07:47, AUDRAIN LUC <LAUDRAIN@hachette-livre.fr<mailto:LAUDRAIN@hachette-livre.fr>> wrote:

Snippet : if I request http://www.example.org/A!B then the server is supposed to deliver http://www.example.org/A!B to the client
This means that A¡B as a sub-resource can be served by the server. Depending on the kind of resource, it may not « naturally »  exists .

If it’s a specific position in an audio or vidéo file, it may be fine in streaming, but as a position in text, can the server send this specific portion of text without sending the beginning of the HTML file?

I am not sure I 100% understand the question.

By default, http://www.example.org/A!B and http://www.example.org/A are two completely different resources, not unlike http://www.example.org/A is completely different from http://www.example.org/C. Of course, the server can implement some tricks whereby the '!' character is interpreted in a particular way, but that is really a matter of server setup/programming/whatever. The '!' character is nothing special, afaik.

But I am not sure I answered your question…

Ivan





De : Shane McCarron <shane@aptest.com<mailto:shane@aptest.com>>
Date : mardi 22 décembre 2015 03:10
À : Leonard Rosenthol <lrosenth@adobe.com<mailto:lrosenth@adobe.com>>
Cc : Romain Deltour <rdeltour@gmail.com<mailto:rdeltour@gmail.com>>, Ivan Herman <ivan@w3.org<mailto:ivan@w3.org>>, Bill Kasdorf <bkasdorf@apexcovantage.com<mailto:bkasdorf@apexcovantage.com>>, Tzviya Siegman <tsiegman@wiley.com<mailto:tsiegman@wiley.com>>, W3C Digital Publishing IG <public-digipub-ig@w3.org<mailto:public-digipub-ig@w3.org>>
Objet : Re: While it is still fresh in our minds: '!' is not just a funny fragment identifier...
Renvoyer - De : <public-digipub-ig@w3.org<mailto:public-digipub-ig@w3.org>>
Renvoyer - Date : mardi 22 décembre 2015 03:11

I am personally wary of any use of '#' in a URL, even if it is in a different scheme.  While it would be perfectly legitimate to define and register a new scheme that has difference semantics for '#', it would be potentially confusing for developers.  I am sure there is some other separator you could use if you really want to identify a sub-resource.  Heck, you could even make it part of a query string.

On Mon, Dec 21, 2015 at 6:09 PM, Leonard Rosenthol <lrosenth@adobe.com<mailto:lrosenth@adobe.com>> wrote:
I would also add that it would be extremely valuable that any such fragment idents for PWP be format agnostic, since we are already seeing that EPUB is but a single profile of PWP and that there may be others – and these idents need to work for all.

Leonard

From: Romain Deltour [mailto:rdeltour@gmail.com<mailto:rdeltour@gmail.com>]
Sent: Monday, December 21, 2015 1:17 PM
To: Ivan Herman <ivan@w3.org<mailto:ivan@w3.org>>
Cc: Bill Kasdorf <bkasdorf@apexcovantage.com<mailto:bkasdorf@apexcovantage.com>>; Tzviya Siegman <tsiegman@wiley.com<mailto:tsiegman@wiley.com>>; W3C Digital Publishing IG <public-digipub-ig@w3.org<mailto:public-digipub-ig@w3.org>>
Subject: Re: While it is still fresh in our minds: '!' is not just a funny fragment identifier...


This is a major difference that we should not forget about.

Absolutely, right.

I was more thinking in terms of spec work:  we should not try to (re)invent the wheel and touch fragment IDs where they're already well-defined (like HTML), but on the other hand, for new media types (for instance a JSON PWP manifest?) we have new grounds to explore and it may be relevant to consider at a fragment identifier-based approach (which is, as you correctly point out, technically different from a custom-URL-separator-based approach).

Romain.

On 21 Dec 2015, at 18:21, Ivan Herman <ivan@w3.org<mailto:ivan@w3.org>> wrote:

This came up today, I think maybe Romain mentioned it: that the '!' approach for content URL looks very much like a fragment ID, so why do we make a differentiation? (But I may have misunderstood the remark, in which case my apologies!)

There is one aspect that we should not forget about where '!' and '#' are very different. Per HTTP the fragment identifier is resolved, and acted upon, on the client side. Ie, the approach is that if I request

http://www.example.org/A#B

then the GET request will deliver the http://www.example.org/A as a whole to the client, which will then select, in a second step, B out of A.

However, a '!' is a bona fide part of a URI. Ie, if I request

http://www.example.org/A!B

then the server is supposed to deliver http://www.example.org/A!B to the client, not http://www.example.org/A (whatever that is).

This is a major difference that we should not forget about.

Happy holidays and lots of rest to all of you/us!

Ivan



----
Ivan Herman, W3C
Digital Publishing Lead
Home: http://www.w3.org/People/Ivan/
mobile: +31-641044153<tel:%2B31-641044153>
ORCID ID: http://orcid.org/0000-0003-0782-2704







--
Shane McCarron
Managing Director, Applied Testing and Technology, Inc.


----
Ivan Herman, W3C
Digital Publishing Lead
Home: http://www.w3.org/People/Ivan/
mobile: +31-641044153
ORCID ID: http://orcid.org/0000-0003-0782-2704






----
Ivan Herman, W3C
Digital Publishing Lead
Home: http://www.w3.org/People/Ivan/
mobile: +31-641044153
ORCID ID: http://orcid.org/0000-0003-0782-2704