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Re: (Possibly) core issue on identification with EPUB-WEB, packaging, fragments...

From: Nick Ruffilo <nickruffilo@gmail.com>
Date: Mon, 1 Jun 2015 11:03:04 -0400
Message-ID: <CA+Dds5_+O1jWXu6erTfTakUWjd=4DLG6k++B+yzfmd7-KGx9Vw@mail.gmail.com>
To: Ivan Herman <ivan@w3.org>
Cc: W3C Digital Publishing IG <public-digipub-ig@w3.org>, Ralph Swick <swick@w3.org>
Ivan,

Yes, I'm saying that the server would unpack & provide only the manifest &
OPF etc.  It would then be the client who requests specific items (or all
items) within the package.

While a server may not be able to do that today, there's nothing stopping a
server from unzipping that epub and doing it today...

There are also existing apache extensions that let you utilize a ZIP file
as a directory, so while it needs to be installed, it does work and enabled
people to utilize that information today.

The ability to send just the manifest does not exist, but I am not sure
that's a real issue, you could gracefully degrade by:

1) If the server CANNOT handle sending the manifest, send the entire epub
to the client, let the client deal with it
2) if the server CAN handle sending the manifest, awesome.

#2 isn't a great solution for very large epubs, but services that are
releasing very large epubs can just ensure their servers support sending
the manifest.

On Mon, Jun 1, 2015 at 10:58 AM, Ivan Herman <ivan@w3.org> wrote:

>
> > On 01 Jun 2015, at 16:11 , Nick Ruffilo <nickruffilo@gmail.com> wrote:
> >
> > What if we leave it up to the client/server to determine what the root
> of the package is and handle it approrpiately?
> >
> > So, an epub-web object (or whatever we call it) might live at :
> //my/item/awesome.epub
> >
> > To address a specific FILE in that, you go to
> //my/item/awesome.epub/text/chap2.html
> >
> > To get to a fragment, you just use # in reference to whatever the
> fragment is:
> > //my/item/awesome.epub/text/chap2.html#first_header
> > //my/item/awesome.epub#SomeCrazyTextRangeIdentifier
> >
> > If run on a server, it would be the server's job to extract the
> appropriate package files (when thinking about epub, the OPF for example)
> and provide that to the client, who can then determine the resources it
> needs and request them from the server.
>
> I am not sure what you mean. Do you mean the server
>
> - unpacks the package and returns the html file (chap2.html); or
> - sends the full package to the client that would then take care of
> unpackaging?
>
> The first one is what I referred to in Con 1.1; the second is Con 1.2.
>
> Actually, an extra 'Con' to 1.1 is that we would need special servers. Ie,
> a person cannot 'just' put an EPUB-WEB document on a Web site (eg, a self
> publisher) unless he/she installs an extension to the server. And that may
> be a drag.
>
> >
> > When run LOCALLY, the client will simply extract the package files
> directly.  Otherwise there is no duplication of work or resources, etc.
> >
> > There was a note about the fragment (things after the #) not being sent
> to the server.  If that is truly the case - and not just that the server
> ignores it - a DIFFERENT marker - what - i have no idea…
>
> I do not think the fragment is really a problem. Once the client has the
> resource, it can take care of it.
>
> Ivan
>
>
> >
> > -Nick
> >
> > On Mon, Jun 1, 2015 at 6:22 AM, Ivan Herman <ivan@w3.org> wrote:
> > Hi all,
> >
> > my sincere apologies for the length of this mail, but I thougt it would
> be worthwhile to get some issues written down to clarify our discussions...
> >
> > On the F2F meeting I made the claim that the identifier/fragment issue
> may be the most tricky one facing us around EPUB-WEB. I thought it is worth
> writing this down; maybe somebody can also prove me wrong that this is not
> such a complex issue after all. Actually, what is below is a summary of a
> very short email/personal discussion Markus, Tzviya, and I had on the
> matter after the F2F. (At some point it is probably worth writing down the
> conclusions of this thread somewhere on the wiki.)
> >
> > With that, here is where I see a real problem.
> >
> > Let us consider a Packaged Document. The URL of this document is
> http://www.example.org/doc. The document includes, among others, chapter
> 2 in file chap2.html. This has a section whose ID is 'sec' (for the sake of
> simplicity, I consider here the simplest and best known fragment used in an
> HTML file, ie, using the @id attribute on a, say, <h1> element). The
> question arising is: what is the full URI for that section? Or, to be more
> exact, what is the full, *canonical* URI for that section, ie, a URI that
> is independent on whether the document is off-line or on-line?
> >
> > An Aside: How do URI-s work?
> > ----------------------------
> >
> > Tzviya told me privately that not everyone on the group may know how
> exactly URI-s and fragments work in browsers and on the Web. So maybe just
> a few words may be relevant here. If you know this, my apologies, you can
> just skip this part.
> >
> > A URL consists of, roughly, two parts:
> >
> > - A "primary" address that identifies the resource somewhere on the web.
> Say, 'http://xyx.example.com/mydoc'
> > - A "fragment", that is added after the '#' sign, which identifies
> something *within* the resource; say, 'mysection'
> >
> > There are two steps in handling this to take into account:
> >
> > - There can be *only one fragment id in a URL*, ie, only one occurence
> of '#'. What is after the '#' is interpreted in accordance with a
> corresponding specification that is bound to the media type of the resource
> >
> > - A Web browser interprets the fragment locally. Ie, if it gets '
> http://xyx.example.com/mydoc#mysection' it
> >         1. strips the fragment
> >         2. it issues a request, through the HTTP protocol, for '/mydoc'
> to the 'http://xyx.example.com' server
> >         3. it gets the full resource and then uses the fragment (i.e.,
> 'mysection') to identify something within the returned resource.
> >
> >
> > What is the URI with fragment for section 'sec' in a package?
> > -------------------------------------------------------------
> >
> > (For the sake of this discussion I refer to the way the packaging
> specification works in terms of fragments.)
> >
> > 1. If http://www.example.org/doc refers to a real, physical package on
> the Web, accessing 'sec' chap2.html, using the current fragment
> specification in the packaging document, would be:
> >
> > http://www.example.org/doc#url=/chap2.html;fragment=sec
> >
> > meaning:
> >         1. The client retrieves the package http://www.example.org/doc
> >         2. Unpackages the package in a local cache (or equivalent)
> >         3. It interprets the fragment 'url=/chap2.html;fragment=sec' by
> (per the current specification of packaging) by
> >                 3.1. identifying the 'part' within the package, yielding
> 'chap2.html'
> >                 3.2. 'chap2.html' is an HTML file; because the server
> knows how to identify something within the file with a fragment, ie, it
> gets to section 'sec'
> >
> > It is important to realize that, in this model, the 'unpackaging' is
> done by the client (the browser i.e., the reading system)
> >
> > 2. If the package is just 'virtual', ie, all documents are on the Web,
> then there is of course a much simpler approach. The URL of the section is
> >
> > http://www.example.org/doc/chap2.html#sec
> >
> > meaning
> >         1. The client retrieves the HTML document
> http://www.example.org/doc/chap2.html
> >         2. It knows how to identify something within the HTML file with
> a fragment, ie, it gets to section 'sec'
> >
> >
> > Back to the original question: what is the 'canonical' URI with fragment?
> > -------------------------------------------------------------------------
> >
> > It should be one of the two above. However, both have issues:
> >
> > A. http://www.example.org/doc/chap2.html#sec
> >
> > Pro: this is the 'natural', Web way.
> >
> > Con 1: *if* the document is, in fact, a real package then there are two
> possible approaches to handle this:
> >
> > Con 1.1: The *server* handles the unpackaging. Ie, it should be in
> position to analyze the URL it receives, realize that there is a 'package'
> in between and do an unpackaging. What this would mean is that the client
> would have to make requests for all chapters separately, which is not
> optimal (although it can of course be cached)/
> >
> > Con 1.2: The *client* handles unpackaging. This would require a
> different server-client protocol, namely:
> >         1. The client issues a request to '
> http://www.example.org/doc/chap2.html'
> >         2. The server returns 'http://www.example.org/doc/' as a
> package instead of the original chap2.html file (ie, the server should know
> that this is part of a package through some redirection)
> >         3. The client should then unpack and locate the chap2.html file
> in the package
> >         4. the fragment should be identified and handled.
> >
> > Steps 1-2-3 is not the current practice on the Web in terms of Web
> Architecture: a client does not 'decompose' the 'primary' part of a URL
> (beyond separating the server's identification from the part within that
> server). It is unclear whether changing that is a viable/acceptable for the
> browsers, and for the overal Web Architecture; it certainly requires a
> discussion with the TAG.
> >
> > Con 2: If the URL is, in fact, a file:///... type one, this means that,
> for that case, the unpackaging must be done on the client. Ie, there may be
> duplication of functionality with the server and the client, which is not
> optimal.
> >
> > B.  http://www.example.org/doc#url=/chap2.html;fragment=sec
> >
> > Pro: this works for a package.
> >
> > For a document on the Web, it may also work if there is a 'conceptual'
> entity on the Web for the document. I.e., http://www.example.org/doc
> returns some sort of an information to the client that this is, fact, a
> 'virtual' package, and then the server can issue a new request to
> http://www.example.org/doc/chap2.html and take it from there.
> >
> > (Note that, regardless of the original issue, having a 'conceptual'
> package handle for a document may not be a bad thing!)
> >
> > Con: The URL form is (much) more complex, and may be in danger of being
> ignored for documents that are on the Web only.
> >
> > Personally, I do not have a clear solution in my head. Hence this mail,
> trying to see how we can move on...
> >
> > Let me also add another remark, coming originally from Tzviya, just to
> add it to the mix: "We need to think about situations such as multiple
> authors creating one package or peer review (one or many authors + one or
> many editors submit article + data set to journal for review. It undergoes
> peer review by one or many reviewers. Journal rejects the article.
> Something happens to the reviews, and the package is submitted to a second
> journal) and so on.) In scenarios like this, the concept of versioning and
> revisioning are a lot more important. It may be covered by OA. I don’t know
> that we can resolve versioning with an identifier."
> >
> > (Again, apologies to be so verbose…)
> >
> > Ivan
> >
> >
> >
> >
> > ----
> > Ivan Herman, W3C
> > Digital Publishing Activity Lead
> > Home: http://www.w3.org/People/Ivan/
> > mobile: +31-641044153
> > ORCID ID: http://orcid.org/0000-0003-0782-2704
> >
> >
> >
> >
> >
> >
> >
> > --
> > - Nick Ruffilo
> > @NickRuffilo
> > http://Aerbook.com
> > http://ZenOfTechnology.com
> >
>
>
> ----
> Ivan Herman, W3C
> Digital Publishing Activity Lead
> Home: http://www.w3.org/People/Ivan/
> mobile: +31-641044153
> ORCID ID: http://orcid.org/0000-0003-0782-2704
>
>
>
>
>


-- 
- Nick Ruffilo
@NickRuffilo
http://Aerbook.com
http://ZenOfTechnology.com <http://zenoftechnology.com/>
Received on Monday, 1 June 2015 15:03:33 UTC

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