[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> 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 <http://www.example.org/A!B> and http://www.example.org/A <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? <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 <http://www.example.org/A> is the URL yielding the PWP manifest (or something similar)
	• http://www.example.org/A!B <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 <http://www.example.org/A!B> then the server is supposed to deliver http://www.example.org/A!B <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 <http://www.example.org/A!B> and http://www.example.org/A <http://www.example.org/A> are two completely different resources, not unlike http://www.example.org/A <http://www.example.org/A> is completely different from http://www.example.org/C <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 <http://www.example.org/A#B>
>>>> 
>>>> then the GET request will deliver the http://www.example.org/A <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 <http://www.example.org/A!B>
>>>> 
>>>> then the server is supposed to deliver http://www.example.org/A!B <http://www.example.org/A!B> to the client, not http://www.example.org/A <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/ <http://www.w3.org/People/Ivan/>
>>>> mobile: +31-641044153 <tel:%2B31-641044153>
>>>> ORCID ID: http://orcid.org/0000-0003-0782-2704 <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/ <http://www.w3.org/People/Ivan/>
> mobile: +31-641044153
> ORCID ID: http://orcid.org/0000-0003-0782-2704 <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

Received on Tuesday, 22 December 2015 08:34:27 UTC