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Re: [dpub-loc] 20160217 minutes

From: Daniel Weck <daniel.weck@gmail.com>
Date: Thu, 18 Feb 2016 19:12:26 +0000
Message-ID: <CA+FkZ9GrUDi7o=TpkY9sm7Nj=_u_d5uF71NYxKC_kAEG97a+uA@mail.gmail.com>
To: Leonard Rosenthol <lrosenth@adobe.com>
Cc: Romain Deltour <rdeltour@gmail.com>, Herman Ivan <ivan@w3.org>, "DPUB mailing list (public-digipub-ig@w3.org)" <public-digipub-ig@w3.org>
Leonard, in your view, would you answer "yes" to the question at the bottom
of my email: "Is this out of scope?"
https://lists.w3.org/Archives/Public/public-digipub-ig/2016Feb/0120.html
That would help me understand the bigger picture. Many thanks.
/Dan
On 18 Feb 2016 6:08 p.m., "Leonard Rosenthol" <lrosenth@adobe.com> wrote:

> >My example is meant to illustrate that a dumb server can return a static
> JSON file, with zero PWP awareness (just URLs and associated
> Content->Types). I just want to have the option to: edit a bunch of files
> locally on my machine, upload to my HTTP server, profit.
> >
> But it cannot.  And that's my point.
>
>
> >That's the API contract, I am agnostic to the "implementation" details.
> >
> You are, as the client.  But the server NEEDS to be able to implement that
> contract, and thus a smart server.
>
> Leonard
>
>
> From: Daniel Weck <daniel.weck@gmail.com>
> Date: Thursday, February 18, 2016 at 11:46 AM
> To: Leonard Rosenthol <lrosenth@adobe.com>
> Cc: "DPUB mailing list (public-digipub-ig@w3.org)" <
> public-digipub-ig@w3.org>, Herman Ivan <ivan@w3.org>, Romain <
> rdeltour@gmail.com>
> Subject: Re: [dpub-loc] 20160217 minutes
>
>
> On 18 Feb 2016 2:14 p.m., "Leonard Rosenthol" <lrosenth@adobe.com> wrote:
> >
> > Great example! GitHub is (in this context) a smart server that
> implements a rich REST API.  And in fact, their API uses the same content
> negotiation model that Ivan and I are proposing (as one option).   See <
> https://developer.github.com/v3/media/> for a discussion of how they use
> media types and Accept header.
>
> DANW:
> Sure, GitHub is clever. But my example makes a point of illustrating a
> dumb curl request :)
> (and a simple JSON body payload in the response)
>
> > So yes, if there is a PWP-aware server that is hosting the content, then
> it can do any/all of the things that you’ve suggested. I don’t think we
> have a preference (as yet) for which of the many choices are available.
>
> DANW:
> My example is meant to illustrate that a dumb server can return a static
> JSON file, with zero PWP awareness (just URLs and associated
> Content-Types). I just want to have the option to: edit a bunch of files
> locally on my machine, upload to my HTTP server, profit.
>
> > This is also true for trying to reach inside of the PWP (eg.
> https://domain.com/another/path/to/book1/manifest.json) unless it just so
> happens to be stored unpacked (on either a smart or dumb server).  Because
> if it was stored packed - you’d want that same URL to work too - but that
> would also require the smart server.
>
> DANW:
> Agreed. As the consumer of the above URL, all I  want is a JSON body
> payload as a response to my HTTP request. I do not need/want to know
> whether this originates from a static file, a blob from a database, an
> inflated data stream from the packed PWP archive, or witchcraft. That's the
> API contract, I am agnostic to the "implementation" details.
>
> > But if all you have is a dumb server - one that you can’t configure (eg.
> DropBox or Google Drive) - then we need to put all the smarts into the
> client to be able to handle all the possible permutations.   And maybe
> that’s OK if this is the expected case - but I hope not if we really want
> PWP to be a “native” part of the web (which includes both clients AND
> servers).
>
> DANW:
> Great example. I want to be able to edit unpacked PWP contents in my local
> DropBox folder, and have my users / consumers access this content over
> HTTP. As a matter of fact, we already do this with exploded EPUBs, OPDS,
> using a reading system that just fetches typed payloads from simple URL
> requests (DropBox is configured with CORS headers by default, so this helps
> a bit). No content negotiation of any kind, by the way.
>
> Is this out of scope?
>
> Thanks! dan
>
> >
> >
> >
> > On 2/18/16, 8:04 AM, "Daniel Weck" <daniel.weck@gmail.com> wrote:
> >
> > >Hello,
> > >
> > >here's a concrete example (unrelated to PWP) which I think illustrates
> > >the comments made during the concall, regarding content negotiation
> > >vs. dereferencing URL endpoints to "meta" data about the publication
> > >locators for unpacked / packed states.
> > >
> > >Let's consider the GitHub HTTP API, the w3c/dpub-pwp-loc GitHub
> > >repository, and the README.md file located at the root of the
> > >gh-branch. There's a "canonical" URL for that (you can safely click on
> > >the links below):
> > >
> > >curl --head https://api.github.com/repos/w3c/dpub-pwp-loc/readme
> > >==> Content-Type: application/json; charset=utf-8
> > >
> > >curl https://api.github.com/repos/w3c/dpub-pwp-loc/readme
> > >==> "url": "
> https://api.github.com/repos/w3c/dpub-pwp-loc/contents/README.md?ref=gh-pages
> "
> > >
> > >As a consumer of that JSON-based API, I can query the actual payload
> > >that I'm interested in:
> > >curl
> https://api.github.com/repos/w3c/dpub-pwp-loc/contents/README.md?ref=gh-pages
> > >==> "content": "BASE64"
> > >
> > >
> > >Now, back to PWP:
> > >
> > >State-agnostic "canonical" URL:
> > >https://domain.com/path/to/book1
> > >(note that this could also be a totally different syntax, e.g.
> > >https://domain.com/info/?get=book1 or
> > >https://domain.com/book1?get=info etc. for as long as a request
> > >returns a content-type that a PWP processor / reading-system can
> > >consume, e.g. application/json or application/pwp-info+json ... or XML
> > >/ whatever)
> > >A simple request to this URL could return (minimal JSON example, just
> > >for illustration purposes):
> > >{
> > >    "packed": "https://domain.com/path/to/book1.pwp",
> > >    "unpacked":
> > >"https://domain.com/another/path/to/book1/manifest.json"  /// (or
> > >container.xml, or package.opf ... :)
> > >}
> > >
> > >Once again, there is no naming convention / constraint on the "packed"
> > >URL https://domain.com/path/to/book1.pwp which could be
> > >https://domain.com/download/book1 or
> > >https://download.domain.com/?get=book1 , as long as a request returns
> > >a payload with content-type application/pwp+zip (for example). Note
> > >that the book1.pwp archive in my example would contain the "main entry
> > >point" manifest.json (thus why I made a parallel above with EPUB
> > >container.xml or package.opf)
> > >
> > >The "unpacked" URL path
> > >https://domain.com/another/path/to/book1/manifest.json does not have
> > >to represent the actual file structure on the server, but it's a
> > >useful syntactical convention because other resource files in the PWP
> > >would probably have similarly-rooted relative locator paths (against a
> > >given base href), e.g.:
> > >https://domain.com/another/path/to/book1/index.html
> > >https://domain.com/another/path/to/book1/images/logo.png
> > >In other words, if the packed book1.pwp contains index.html with <img
> > >src="./images/logo.png" />, it does make sense for the online unpacked
> > >state to use the same path references (as per the example URLs above).
> > >Publishers may have the option to route URLs any way they like, e.g.
> > ><img src="?get_image=logo.png" />, but we know there is the issue of
> > >mapping document URLs in packed/unpacked states with some canonical
> > >locator, so that annotation targets can be referenced and resolved
> > >consistently. So it would greatly help if the file structure inside
> > >the packed book1.pwp was replicated exactly in the URL patterns used
> > >for deploying the unpacked state.
> > >
> > >To conclude, I am probably missing something (Ivan and Leonard, you
> > >guys are ahead of the curve compared to me), but I hope I managed to
> > >convey useful arguments. Personally, as a developer involved in
> > >reading-system implementations, and as someone who would like to
> > >continue deploying content with minimal server-side requirements, I am
> > >not yet convinced that content negotiation is needed here. As an
> > >optional feature, sure, but not as the lowest common denominator.
> > >
> > >Thanks for listening :)
> > >Regards, Dan
> > >
> > >
> > >
> > >On Thu, Feb 18, 2016 at 12:04 PM, Ivan Herman <ivan@w3.org> wrote:
> > >> With the caveat that the minutes are always difficult to read
> (Romain, that
> > >> is not your fault, it is the case for most of the minutes; I know
> only a few
> > >> people who write perfect minutes, and I am certainly not among them)
> maybe
> > >> some comments on my side. More about this next time we can all talk
> > >> (although it seems that this will only be in two weeks, due to the
> Baltimore
> > >> EDUPUB meeting).
> > >>
> > >> First of all, this comment:
> > >>
> > >> [[[
> > >> rom: my issue is that the spec doesn't say "if Lu exists then L must
> be Lu",
> > >> I think we should consider it
> > >> ]]]
> > >>
> > >> I do not see why we should say anything like that. It is of course
> correct
> > >> that, in many cases, it makes a lot of sense to have Lu=L. But I do
> not see
> > >> why we should restrict it this way. In general, the approach I tried
> to
> > >> follow in my writeup is to be as permissive as possible and put the
> minimum
> > >> possible hard requirements on the locator setup. It is probably worth
> adding
> > >> a note in the text (or the more final text) that Lu may be equal to L
> (in
> > >> fact, this may very well be a widely used approach) but I would not
> want to
> > >> go beyond that.
> > >>
> > >> Then there is the whole issue about content negotiations… It seems
> that we
> > >> have a disagreement on the value and usage of content negotiations. I
> do not
> > >> agree with Daniel's statement that "in a RESTful API the URL would
> > >> consistently return the same content type". It is certainly not the
> > >> practice, nor should it be. Content negotiation is widely used when
> tools
> > >> want to retrieve, for example the best syntax that encodes a
> particular
> > >> information (typical example is in RDF land, where tools may or may
> not have
> > >> parsers for a particular RDF serialization), this is how dbpedia is
> set up
> > >> etc. (I did told you about the way RDF namespace documents are set up
> on our
> > >> site, for example. It is pretty much general practice to do that.) I
> must
> > >> admit I also do not agree with Daniel's remark on "content
> negotiation based
> > >> on (sophisticated) HTTP headers sounds counter intuitive". Content
> > >> negotiations is certainly very intuitive to me...
> > >>
> > >> All that being said, and that is where maybe there is actually a minor
> > >> disagreement between Leonard and I: I do not say that content
> negotiation is
> > >> the only approach to set up a server storage. The text I wrote is
> > >> deliberately open ended insofar as it described what the client
> expectation
> > >> is when that GET request is issued in general terms, and the choice
> among
> > >> the various alternatives are all the server's. The list of possible
> server
> > >> behaviours in the text are possible alternatives, instead of hard
> > >> requirements. The client is responsible in following the various
> possible
> > >> paths and, maybe, we will have to describe those possibilities later
> in more
> > >> details (precise usage of the LINK header, the <link> element, media
> types,
> > >> etc), but that gives the liberty to set up the server the way the
> publisher
> > >> wants. If we accept this approach, ie, that the client has some
> complexity
> > >> to resolve in favour of a variety of possible server setups, then I
> do not
> > >> think there is a major disagreement among us.
> > >>
> > >> Talk to you guys later…
> > >>
> > >> Ivan
> > >>
> > >> B.t.w., a more general and slightly philosophical comment: we should
> not be
> > >> afraid of really using HTTP:-) The various header information in both
> the
> > >> request and response headers of an HTTP request/response are very
> rich and
> > >> sophisticated. There are many situations, on expiration dates, on
> security,
> > >> etc, and of course content negotiations that can be expressed via
> these HTTP
> > >> headers, and we should not shy away using those whenever we can and
> it makes
> > >> sense. As I showed in one of may mails it is not that complex to set
> up
> > >> (actually, and to be fair, setting up content negotiations is
> probably the
> > >> more complex thing, I accept that).
> > >>
> > >> If you are interested by the various possibilities, this site may be
> of
> > >> interest:
> > >>
> > >> https://github.com/dret/sedola/blob/master/MD/headers.md
> > >>
> > >>
> > >>
> > >> On 18 Feb 2016, at 09:24, Romain <rdeltour@gmail.com> wrote:
> > >>
> > >>
> > >> On 18 Feb 2016, at 02:49, Leonard Rosenthol <lrosenth@adobe.com>
> wrote:
> > >>
> > >> Actually, the big issue that I took away from the minutes is that
> ivan and I
> > >> are in agreement that content negotiation (via standard web technique
> incl.
> > >> the Accept header) is the proper way for the client & server to
> decide what
> > >> to return on the GET from the canonical locator.   Daniel, however,
> appears
> > >> (from the minutes) to be promoting a completely different approach.
> > >>
> > >>
> > >> As stated before [1], I am absolutely not convinced that content
> negotiation
> > >> is a good approach.
> > >> I want to upload a PWP tomorrow to a static file hosting service; if
> conneg
> > >> is required I can't do that.
> > >>
> > >> More to the point: how to you GET the (manifest + Lu + Lp) info with
> the
> > >> conneg solution? Maybe I just miss something.
> > >>
> > >> Finally, may I turn the question the other way around: what are the
> benefits
> > >> of content negotiation for the canonical locator? (compared to an
> > >> alternative approach with explicit links in the GET answer (headers or
> > >> payload).
> > >>
> > >> Thanks,
> > >> Romain.
> > >>
> > >> [1]
> https://lists.w3.org/Archives/Public/public-digipub-ig/2016Jan/0136.html
> > >>
> > >>
> > >> Daniel, if you can explain why you want to do something different
> from the
> > >> standard web/REST model, I’d like to understand.
> > >>
> > >> Leonard
> > >>
> > >> From: Romain <rdeltour@gmail.com>
> > >> Date: Wednesday, February 17, 2016 at 6:26 PM
> > >> To: Daniel Weck <daniel.weck@gmail.com>, Leonard Rosenthol
> > >> <lrosenth@adobe.com>
> > >> Cc: "DPUB mailing list (public-digipub-ig@w3.org)"
> > >> <public-digipub-ig@w3.org>, Tzviya Siegman <tsiegman@wiley.com>
> > >> Subject: Re: [dpub-loc] 20160217 minutes
> > >>
> > >> On 17 Feb 2016, at 23:12, Daniel Weck <daniel.weck@gmail.com> wrote:
> > >>
> > >> Hi Leonard, that's quite a bold statement, but I suspect the minutes
> could
> > >> do with a few corrections.
> > >>
> > >> My bad if the minutes are inaccurate, please feel free to amend. It
> was a
> > >> bit frustrating too: several times I wanted to talk or precise a
> point but
> > >> was busy typing.
> > >>
> > >> At any rate, I look forward to the recap from you and Ivan at the next
> > >> opportunity. PS: it was a small quorum on this concall, but I was
> under the
> > >> impression that the participants agreed on the broad lines of your
> proposal,
> > >> with only details to clarify.
> > >>
> > >> My impression is that participants generally agreed with the
> presentation of
> > >> the issues and some principles. I believe that the main point that is
> still
> > >> controversial is really what should be the answer to a GET on the
> canonical
> > >> locator.
> > >>
> > >>> I think we need to go do this over again next week – which si
> extremely
> > >>> unfortunate.
> > >>
> > >>
> > >> If I'm not mistaken Matt, Markus, Tzviya and I won't be able to attend
> > >> (EDUPUB summit).
> > >>
> > >> Romain.
> > >>
> > >> Regards, Daniel
> > >>
> > >> On 17 Feb 2016 9:17 p.m., "Leonard Rosenthol" <lrosenth@adobe.com>
> wrote:
> > >>>
> > >>> Sorry that I was unable to attend today, especially since the
> discussion
> > >>> (based on the minutes) seems to completely undo all the work that
> Ivan,
> > >>> myself and others did on the mailing list during the past week.   The
> > >>> position presented by Daniel is the exact opposite of what Ivan’s
> musings
> > >>> (adjusted based on mail conversations) presented.
> > >>>
> > >>> I think we need to go do this over again next week – which si
> extremely
> > >>> unfortunate.
> > >>>
> > >>> Leonard
> > >>>
> > >>> Fro  "Siegman, Tzviya - Hoboken" <tsiegman@wiley.com>
> > >>> Date: Wednesday, February 17, 2016 at 11:46 AM
> > >>> To: "DPUB mailing list (public-digipub-ig@w3.org)"
> > >>> <public-digipub-ig@w3.org>
> > >>> Subject: [dpub-loc] 20160217 minutes
> > >>> Resent-From: <public-digipub-ig@w3.org>
> > >>> Resent-Date: Wednesday, February 17, 2016 at 11:48 AM
> > >>>
> > >>> Minutes from today’s meeting:
> > >>> https://www.w3.org/2016/02/17-dpub-loc-minutes.html
> > >>>
> > >>> Tzviya Siegman
> > >>> Digital Book Standards & Capabilities Lead
> > >>> Wiley
> > >>> 201-748-6884
> > >>> tsiegman@wiley.com
> > >>>
> > >>
> > >>
> > >>
> > >>
> > >>
> > >> ----
> > >> 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 Thursday, 18 February 2016 19:13:00 UTC

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