Portable Web Pub­li­ca­tions

These Slides are Avail­able on the Web

See: http://www.w3.org/2016/Talks/EPUBSummit-IH/

(Slides are in HTML)

About W3C: “Leading the Web to its Full Potential”

• Founded in 1994, and di­rected by Tim Bern­ers-Lee, the In­ven­tor of the Web
• Mem­ber or­ga­ni­za­tion with cca. 420 mem­bers
• Cca. 75 staff bound to “hosts” in the USA (MIT), China (Bei­hang Uni­ver­sity), Japan (Keio Uni­ver­sity), and France (ERCIM)
• Fo­cuses on Web ecosys­tem: users, de­vel­op­ers, browsers, as well as spe­cific in­dus­try re­quire­ments brought by in­dus­try seg­ments

Digital Publishing Interest Group (DPUB IG) Origins

• W3C and IDPF or­ga­nized a se­ries of work­shops in 2012 to cre­ate a miss­ing syn­ergy among the Web and Pub­lish­ing com­mu­ni­ties
• The W3C Dig­i­tal Pub­lish­ing In­ter­est Group was set up in May 2013
• DPUB IG has weekly tele­con­fer­ences and bi-an­nual face to face meet­ings

DPUB IG Mission

• Ex­perts fa­mil­iar with the ins and outs of dig­i­tal pub­lish­ing and its as­so­ci­ated in­dus­try groups iden­tify is­sues that are not ad­dressed by the Open Web Plat­form
• Goal is to raise is­sues to W3C work­ing groups who can up­date or de­velop specs based on the needs of the pub­lish­ing com­mu­nity.
• Work on a fu­ture vi­sion of Dig­i­tal Pub­lish­ing called “Portable Web Pub­li­ca­tions (PWP)”

See our web­site for more de­tail.

Layout and styling

• An evolv­ing doc­u­ment: “Re­quire­ments for Latin Text Lay­out and Pag­i­na­tion”
• De­scribes is­sues like hy­phen­ation, spreads and bleeds, drop caps, pag­i­na­tion, etc.
• Has greatly in­flu­enced some cur­rent CSS Work, e.g. “CSS In­line Lay­out Mod­ule Level 3” (han­dling ini­tial let­ters, drop­caps), or “CSS Gen­er­ated Con­tent for Paged Media Mod­ule” (han­dling run­ning heads and foot­ers)

Priorities for CSS

• An­other evolv­ing doc­u­ment: “Pri­or­i­ties for CSS from the DPUB IG”
• Pro­vides a list of the top CSS pri­or­i­ties, and their cur­rent avail­abil­ity
• Also in­flu­ences the work of the CSS Work­ing Group

Content and markup

• Goal: iden­tify the se­man­tics of the HTML el­e­ments
  • “ab­stract”, “in­dexed term”, “foot­note”, "chap­ter", …
• Ex­press struc­tural in­for­ma­tion (“where can that el­e­ment be used”)
• Do it in a for­ward look­ing way in terms of W3C stan­dards.
  • i.e., move away from epub:type used in EPUB 3
  • the re­sult­ing HTML should be valid
• These terms may be use­ful for the Web at large!

Content and markup: DPUB ARIA module

• A “Dig­i­tal Pub­lish­ing WAI-ARIA mod­ule” is in de­vel­op­ment
  • i.e., pub­lish­ing terms be­come part of ARIA
• A sep­a­rate doc­u­ment de­scribes the map­ping on the Ac­ces­si­bil­ity API-s

<section role="doc-appendix">
  <h1>Appendix A. Historical Timeline</h1>
   …
</section>

Annotations

Note on DPUB Accessibility

What does this mean?

• This means:
  • pub­li­ca­tion con­tent on the Web can be loaded into a browser or a spe­cial­ized reader, what­ever the user prefers
  • a pub­li­ca­tion on a local disc can be pushed onto the Web and used with­out any change
  • con­tent are au­thored re­gard­less of where they are used
  • these are done with­out any user in­ter­ac­tion, pos­si­bly au­to­mat­i­cally

What does this mean?

For example: book in a browser

For example: book in a browser

For example: I may not be online…

For example: scholarly publishing

For example: educational publications

• What is an ed­u­ca­tional pub­li­ca­tion?
  • a book that re­quires of­fline ac­cess?
  • a pack­aged ap­pli­ca­tion with built-in in­ter­ac­tive tests, an­i­mated ex­am­ples?
  • a Web client reach­ing out to Web ser­vices for as­sess­ing test re­sults, to en­cy­clo­pe­dia, …?
  • an in­ter­ac­tive data con­tainer stor­ing var­i­ous data for, e.g., demon­stra­tions?
• The bor­der­line be­tween a “book” and a “(Web) Ap­pli­ca­tion” is be­com­ing blurred…

Advantage for the publishers‘ community

Advantage for the Web community

What is a Portable Web Publication?

• A col­lec­tion of Web re­sources con­sid­ered as one unit
  • this means there is a Web ad­dress for the col­lec­tion (as op­posed to a sin­gle con­stituent)
• The user agent can ren­der its “es­sen­tial con­tent” by re­ly­ing on the Web Re­sources within the same Web Pub­li­ca­tion
  • this en­sures that it can also be con­sid­ered of­fline with­out the dan­ger of dan­gling links
• The same PWP can be of­fline, on­line, archived or not archived…

What kinds of documents are we talking about?

• A jour­nal or mag­a­zine ar­ti­cle, in­clud­ing the rel­e­vant CSS files and im­ages
• An ed­u­ca­tional ar­ti­cle, in­clud­ing the JavaScript to do in­ter­ac­tive ex­er­cises
• A novel or a poem on the Web, in­clud­ing the nec­es­sary fonts, CSS files, etc., to pro­vide the re­quired aes­thet­ics

What kinds of documents are we not talking about?

• A Web mail ap­pli­ca­tion
• A so­cial Web site like Face­book, VK, Ren­ren, or Twit­ter
• A dy­namic page that de­pends on, say, a Javascript li­brary hosted some­where on the cloud

But there are of course differences

• Al­though the we talk about the same PWP, whether of­fline or on­line, but they are ob­vi­ously not 100% iden­ti­cal
• We refer to dif­fer­ent states of the same PWP

Envisioned “states” of a Portable Web Publication

	On­line	Of­fline
Packed	PWP as one archive on a server	PWP as one archive on a local disc
Unpacked	PWP spread over sev­eral files on a server	PWP spread over sev­eral files on a local disc

Envisioned architecture:
a “PWP Processor”

• A con­cep­tual, client-side proces­sor that “hides” the PWP state dif­fer­ences from the ren­der­ing en­gine
• The “main” ren­der­ing en­gine op­er­ates as if it was con­nected to the Web:
  • ac­cess­ing re­sources through HTTP(S)
  • all re­sources are “un­packed”
• The PWP Proces­sor should hide the state dif­fer­ences, pos­si­bly cache re­sources, etc.

Envisioned architecture:
unpacked state

Envisioned architecture:
cached state

Envisioned architecture:
packed state

Advances in modern browsers

• A browser has a hid­den, truly par­al­lel en­gine (a.k.a. “Ser­vice Worker”) at­tached to it
• That en­gine “catches” all calls out to the Web, and:
  • ei­ther lets it through and the orig­i­nal re­quest hap­pens;
  • or per­forms local pro­cess­ing (e.g., gets con­tent from a cache) and re­turns that con­tent in­stead
• The “main” ren­der­ing en­gine is un­aware of the un­der­ly­ing proxy process
  • it op­er­ates as if it was con­nected to the Web in a tra­di­tional way

Not only a wild idea…

• Some prior art ex­ists (e.g., ex­per­i­men­ta­tion by the Rea­d­ium Con­sor­tium)
• An early mock-up of the cur­rent ar­chi­tec­ture has also been im­ple­mented

Is it "addressing" or is it "identification"?

• These two “roles” are dif­fer­ent
• The usual sit­u­a­tion:
  • some form of a URI is used to (uniquely) iden­tify a re­source
  • an HTTP(S) URL is used to ad­dress (or “lo­cate”) a re­source on the Web
• In many cases the two roles co­in­cide, but not al­ways
  • e.g., for a dig­i­tal book:
    • URN:ISBN:1-56592-521-1 iden­ti­fies the pub­li­ca­tion
    • http://www.ex.org/ex.epub ad­dresses a par­tic­u­lar copy

Is it "addressing" or is it "identification"?

• Iden­ti­fi­ca­tion is­sues are han­dled by a num­ber of other or­ga­ni­za­tions (DOI foun­da­tion, In­ter­na­tional ISBN Agency, etc.)
• The work on PWP has to con­cen­trate on lo­ca­tors (i.e., ad­dress­ing)

Three layers of addressing

1. Lo­ca­tor for the PWP it­self:
   http://www.ex.org/MyPWP/
2. Lo­cat­ing a re­source within a PWP:
   http://www.ex.org/MyPWP/Chapter1.html
3. Lo­cat­ing a tar­get within a re­source:
   http://www.ex.org/MyPWP/Chapter1.html#section1

• #3, i.e., “frag­ments” is de­fined for spe­cific media types
• #2 should be just like any other re­sources on the Web, to allow for a smooth state tran­si­tion

Locating the different PWP “states”

• There are, in prac­tice, dif­fer­ent lo­ca­tors
  • to the un­packed ver­sion on the Web:
    http://www.ex.org/MyPWP/dir/
  • to the pack­age:
    http://www.ex.org/MyPWP.pwp
• Which lo­ca­tors should one use? How would in­tra-re­source ad­dress­ing hap­pen?
  • i.e., how should chapter1 refer to chapter2?

Canonical locators

• A PWP must have a Canon­i­cal Lo­ca­tor
  • a state ag­nos­tic lo­ca­tor: http://www.ex.org/MyPWP
• A pub­lished PWP must pro­vide meta­data that in­cludes all the var­i­ous lo­ca­tors
• A PWP Proces­sor must have ac­cess to the full meta­data
• A re­source within a PWP (and, in gen­eral, re­sources in gen­eral) should use the canon­i­cal lo­ca­tor only for in­ter­nal cross-ref­er­ences (or use rel­a­tive URL-s)

The PWP Processor can take care of the rest…

• The proces­sor has an ac­cess to all states and their lo­ca­tors
• It can, if needed, con­vert among URI re­quests com­ing from the ren­derer
• Re­mem­ber:

• A con­cep­tual, client-side proces­sor that “hides” the PWP state dif­fer­ences from the ren­der­ing en­gine
• The “main” ren­der­ing en­gine op­er­ates as if it was con­nected to the Web:
  • ac­cess­ing re­sources through HTTP(S)
  • all re­sources are “un­packed”
• The PWP Proces­sor should hide the state dif­fer­ences, pos­si­bly cache re­sources, etc.

Manifests

• Note the cru­cial im­por­tance of the meta­data
• Some sort of a “man­i­fest” for­mat should be de­fined to hold (among oth­ers) this meta­data
• The man­i­fest will be used for other, more tra­di­tional rea­sons, too:
  • “tra­di­tional” meta­data like au­thor(s), right ex­pres­sions, pub­li­ca­tion dates,…
  • iden­ti­fiers
  • cor­rect read­ing order for the pub­li­ca­tion con­tent
  • etc.

• What is the level of user con­trol of the pre­sen­ta­tion?
• The Web and eBook tra­di­tions are vastly dif­fer­ent:
  • in a browser, the Web de­signer is in full con­trol
    • CSS al­ter­nate style sheets or user style sheets are hardly in use
    • some user in­ter­face as­pects can be con­trolled but only for the browser as a whole
  • in an eBook reader, there is more user con­trol
    • fore­ground/back­ground color
    • choice of fonts
• There is a need to rec­on­cile these tra­di­tions

IDPF, W3C, and others

• On long term, some PWP re­lated stan­dard-track spec­i­fi­ca­tion work may have to be done
  • this re­quires a con­sen­sus and agree­ment of dif­fer­ent com­mu­ni­ties
• IDPF and W3C (and maybe oth­ers?) may cre­ate the nec­es­sary groups, even­tu­ally

DPUB IG and Portable Web Publications

• “Portable Web Pub­li­ca­tions” was, orig­i­nally, a sep­a­rate “vi­sion” doc­u­ment
• Was adopted, for­mally, as part of the group’s work in Sep­tem­ber 2015, and is now pub­lished as an IG doc­u­ment
• The group will con­tribute to the for­mu­la­tion of the PWP tech­ni­cal chal­lenges, to a bet­ter un­der­stand­ing of the re­quire­ments
• PWP is the guid­ing prin­ci­ple for the group’s fur­ther work

PWP vs. EPUB3.1

• PWP does not re­place EPUB 3.1
• Many of the new fea­tures dis­cussed as part of EPUB 3.1 (e.g., struc­tural se­man­tics, man­i­fests) al­ready go in di­rec­tion of some­thing like PWP
• Oth­ers (like the lo­ca­tor struc­ture) from the work on PWP may in­flu­ence the evo­lu­tion of EPUB 3.1, mainly in the area of BFF

Many (most?) things are the same!

• The con­tent of a PWP and EPUB 3.1 are iden­ti­cal
  • usage of HTML, CSS, SVG, SMIL, etc.
• What would change is the “ad­min­is­tra­tive” as­pect of the pub­li­ca­tion (lo­ca­tors, man­i­fest, etc)

PWP and future EPUB-s

• The struc­ture of PWP is very gen­eral
• Spe­cific pub­li­ca­tion areas may need more re­stric­tions and spec­i­fi­ca­tions
  • meta­data vo­cab­u­lar­ies, spe­cific for­mat for glos­saries or in­de­ces,…
  • many of these fea­tures are al­ready de­fined in EPUB 3
• A fu­ture EPUB may be de­fined as a pro­file of PWP
  • tak­ing over or adapt­ing a num­ber of ex­ist­ing parts of EPUB 3.1
  • a bit like EDUPUB is a pro­file of EPUB 3
• There may be other pro­files for, e.g., on­line mag­a­zines

Some references

DPUB IG Wiki

https://www.w3.org/dpub/IG/wiki/Main_Page

Lat­est PWP Of­fi­cial Draft:

http://www.w3.org/TR/pwp/

PWP Ed­i­tors’ draft:

https://w3c.github.io/dpub-pwp/

PWP Issue list:

https://github.com/w3c/dpub-pwp/issues

Thank you for your at­ten­tion!

This pre­sen­ta­tion:

http://www.w3.org/2016/Talks/EPUBSummit-IH/

A com­pan­ion, a bit more tech­ni­cal, pre­sen­ta­tion

http://www.w3.org/2016/Talks/W3CTrack-IH/

My con­tact:

ivan@​w3.​org