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<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" lang="en-US" xml:lang="en-US">
<head>
<meta charset="utf-8" />
<title>Web Publications</title>
<script src="https://www.w3.org/Tools/respec/respec-w3c-common" class="remove" defer="defer"></script>
<script src="common/js/biblio.js" class="remove"></script>
<script src="common/js/orcid.js" class="remove"></script>
<script src="common/js/wp.js" class="remove"></script>
<link href="common/css/common.css" rel="stylesheet" type="text/css" />
<script class="remove">
// <![CDATA[
var respecConfig = {
postProcess: [show_orcid, create_wp],
wg: "Publishing Working Group",
specStatus: "ED",
shortName: "wpub",
previousPublishDate: "2018-01-04",
previousMaturity: "WD",
edDraftURI: "https://w3c.github.io/wpub/",
editors: [
{
"name": "Matt Garrish",
"company": "DAISY Consortium",
"companyURL": "http://www.daisy.org",
"w3cid": 51655
},
{
"name": "Ivan Herman",
"url": "https://www.w3.org/People/Ivan/",
"company": "W3C",
"w3cid": 7382,
"orcid": "0000-0003-0782-2704",
"companyURL": "https://www.w3.org",
}
],
authors: [
{
"name": "Baldur Bjarnason",
"company": "The Rebus Foundation",
"companyURL": "https://reb.us/",
"w3cid": 92101
},
{
"name": "Timothy W. Cole",
"url": "https://www.library.illinois.edu/people/bios/t-cole3/",
"company": "University of Illinois at Urbana-Champaign",
"companyURL": "https://illinois.edu",
"w3cid": 53965,
"orcid": "0000-0002-5906-4581"
},
{
"name": "Dave Cramer",
"company": "Hachette Livre",
"companyURL": "https://hachette.com/",
"w3cid": 65283
},
{
"name": "Hadrien Gardeur",
"company": "Feedbooks",
"companyURL": "https://www.feedbooks.com/",
"w3cid": 97094
},
{
"name": "Florian Rivoal",
"company": "Invited Expert",
"companyURL": "https://florian.rivoal.net/",
"w3cid": 43241
}
],
processVersion: 2018,
includePermalinks: false,
permalinkEdge: true,
permalinkHide: false,
diffTool: "http://www.aptest.com/standards/htmldiff/htmldiff.pl",
wgURI: "https://www.w3.org/publishing/groups/publ-wg/",
wgPublicList: "public-publ-wg",
wgPatentURI: "https://www.w3.org/2004/01/pp-impl/100074/status",
github: {
repoURL: "https://github.com/w3c/wpub/",
branch: "master"
},
localBiblio: biblio
};
// ]]>
</script>
</head>
<body>
<section id="abstract">
<p>This specification defines a collection of information that describes the structure of Web Publications
so that user agents can provide user experiences tailored to reading publications, such as sequential
navigation and offline reading. This information includes the default reading order, a list of
resources, and publication-wide metadata.</p>
</section>
<section id="sotd">
<p>This draft provides a preliminary outline of a Web Publication. Many details are under active
consideration within the Publishing Working Group and are subject to change. The most prominent known
issues have been identified in this document and links provided to comment on them.</p>
</section>
<section id="intro">
<h2>Introduction</h2>
<section id="what-is-wp" class="informative">
<h3>What is a Web Publication</h3>
<p>A <a>Web Publication</a> is a discoverable and identifiable collection of resources. Information
about the Web Publication is expressed in a machine-readable document called a <a>manifest</a>,
which is what enables user agents to understand the bounds of the Web Publication and the connection
between its resources.</p>
<p>The manifest includes metadata that describe the Web Publication, as a publication has an identity
and nature beyond its constituent resources. The manifest also provides a list of all the resources
that belong to the Web Publication and a default reading order, which is how it connects resources
into a single contiguous work.</p>
<p>A Web Publication is discoverable in one of two ways: resources either include a link to the manifest
(via an HTTP Link header or an HTML <code>link</code> element [[!html]]), or the manifest can
be loaded directly by a compatible user agent.</p>
<p>With the establishment of Web Publications, user agents can build new experiences tailored
specifically for their unique reading needs.</p>
<figure id="WP-diagram">
<object data="images/WP-diagram.svg" type="image/svg+xml" aria-describedby="wp-diagram-alt">
<p id="wp-diagram-alt">Flowchart depicts the resources of a Web Publication, their attachment to
a manifest, and its relationship to the infoset.</p>
</object>
<figcaption>Simplified Diagram of the Structure of Web Publications. <br />A <a
href="#WP-diagram-descr">description of the structure diagram</a> is available in the
Appendix. Image available in <a href="images/WP-diagram.svg"
title="SVG image of the structure of Web Publications">SVG</a> and <a
title="PNG image of the structure of Web Publications" href="images/WP-diagram.png">PNG</a>
formats.</figcaption>
</figure>
</section>
<section id="scope" class="informative">
<h3>Scope</h3>
<p>This specification only defines requirements for the production and rendering of valid <a>Web
Publications</a>. As much as possible, it leverages existing Open Web Platform technologies to
achieve its goal—that being to allow for a measure of boundedness on the Web without changing the
way that the Web itself operates.</p>
<p>Moreover, the specification is designed to adapt automatically to updates to Open Web Platform
technologies in order to ensure that Web Publications continue to interoperate seamlessly as the Web
evolves (e.g., by referencing the latest published versions instead of specific dated versions).</p>
<p>Further, this specification does not attempt to constrain the nature of a Web Publication: any type
of work that can be represented on the Web constitutes a potential Web Publication.</p>
<p>The specification is also intended to facilitate different user agent architectures for the
consumption of Web Publications. While a primary goal is that traditional Web user agents (browsers)
will be able to consume Web Publications, this should not limit the capabilities of any other
possible type of user agent (e.g., applications, whether standalone or running within a user agent,
or even Web Publications that include their own user interface). As a result, the specification does
not attempt to architect required solutions for situations whose expected outcome will vary
depending on the nature of the user agent and the expectations of the user (e.g., how to prompt to
initiate a Web Publication, or at what point or how much of a Web Publication to cache for offline
use).</p>
</section>
<section id="relationships">
<h3>Relationship to Other Specifications</h3>
<section id="rel-wam">
<h4>Web App Manifest</h4>
<p class="ednote">We may want to write something here on the relationships…</p>
</section>
</section>
<section id="terminology">
<h3>Terminology</h3>
<p>This document uses terminology defined by the W3C Note "Publishing and Linking on the
Web" [[!publishing-linking]], including, in particular, <a class="externalDFN"
href="https://www.w3.org/TR/publishing-linking/#dfn-user">user</a>, <a class="externalDFN"
href="https://www.w3.org/TR/publishing-linking/#dfn-user-agent">user agent</a>, <a
class="externalDFN" href="https://www.w3.org/TR/publishing-linking/#dfn-browser">browser</a>,
and <a class="externalDFN" href="https://www.w3.org/TR/publishing-linking/#dfn-address"
>address</a>.</p>
<dl>
<dt><dfn data-lt="identifiers">Identifier</dfn></dt>
<dd>
<p>An identifier is metadata that can be used to refer to <a class="externalDFN"
href="https://www.w3.org/TR/publishing-linking/#dfn-web-content">Web Content</a> in a
persistent and unambiguous manner. <abbr title="Uniform Resource Locators">URLs</abbr>,
<abbr title="Uniform Resource Names">URNs</abbr>, <abbr
title="Digital Object Identifiers">DOIs</abbr>, <abbr
title="International Standard Book Numbers">ISBNs</abbr>, and <abbr
title="Persistent Uniform Resource Locators">PURLs</abbr> are all examples of persistent
identifiers frequently used in publishing.</p>
</dd>
<dt><dfn data-lt="Manifests">Manifest</dfn></dt>
<dd>
<p>A manifest represents structured information about a <a>Web Publication</a>, such as
informative metadata, a <a href="#resource-list">list of all resources</a>, and a <a>default
reading order</a>.</p>
</dd>
<dt><dfn>Non-empty</dfn></dt>
<dd>
<p>For the purposes of this specification, non-empty is used to refer to an element, attribute
or property whose text content or value consists of one or more characters after whitespace
normalization, where whitespace normalization rules are defined per the host format.</p>
</dd>
<dt><dfn data-lt="URLs">URL</dfn></dt>
<dd>
<p>The general term <abbr title="Uniform Resource Locator">URL</abbr> is defined by the URL
Standard [[!url]]. It is used as in other <abbr title="World Wide Web Consortium"
>W3C</abbr> specifications, like <abbr title="Hypertext Markup Language"
>HTML</abbr> [[!html]]. In particular, a <abbr title="Uniform Resource Locator"
>URL</abbr> allows for the usage of characters from Unicode following [[!rfc3987]].
See <a href="https://www.w3.org/TR/html/references.html#biblio-url">the note in the HTML5
specification</a> for further details.</p>
</dd>
<dt><dfn data-lt="Web Publications|Web Publication's">Web Publication</dfn></dt>
<dd>
<p>A Web Publication is a collection of one or more resources, organized together through a
<a>manifest</a> into a single logical work with a <a>default reading order</a>. The Web
Publication is uniquely identifiable and presentable using Open Web Platform
technologies.</p>
</dd>
</dl>
</section>
</section>
<section id="conformance">
<section id="conformance-classes">
<h2>Conformance Classes</h2>
<p>This specification defines two conformance classes: one for <a>Web Publications</a> and one for user
agents that process them.</p>
<p id="wp-conformance">A Web Publication conforms to this specification if it meets the following
criteria:</p>
<ul>
<li>it has a <a>manifest</a> that conforms to <a href="#wp-properties-req"></a>;</li>
<li>it adheres to the construction requirements defined in <a href="#wp-construction"></a>.</li>
</ul>
<p id="ua-conformance">A user agent conforms to this specification if it meets the following
criteria:</p>
<ul>
<li>it is capable of generating a conforming <a href="#wp-properties"><abbr title="information set"
>infoset</abbr></a> for a Web Publication.</li>
</ul>
</section>
</section>
<section id="wp-construction">
<h2>Web Publication Construction</h2>
<section id="wp-infoset-manifest" class="informative">
<h3>Infoset and Manifest</h3>
<p>A <a>Web Publication</a> is defined by a set of items known as its <dfn data-lt="infoset">information
set</dfn> (<abbr title="information set">infoset</abbr>). The <abbr title="information set"
>infoset</abbr> is both abstract and concrete. It is abstract in the sense that it represents a
set of information that a user agent has to compile about the Web Publication, but it also becomes
concrete when the user agent creates an internal representation of that information.</p>
<p>A <a>manifest</a>, on the other hand, is a serialization of an <abbr title="information set"
><a>infoset</a></abbr> created by the author of a <a>Web Publication</a>. The manifest is
expressed using the JSON-LD [[!json-ld]] format — a variant of JSON [[ecma-404]] for
expressing linked data. The manifest can be created as a standalone resource or it can be embedded
within an HTML document.</p>
<p>Although the <abbr title="information set">infoset</abbr> is primarily compiled from a Web
Publication's <a>manifest</a>, some information is obtained outside the manifest. The table of
contents, for example, may be referenced from the manifest but is serialized in an HTML
document.</p>
<p>This specification describes the requirements for creating both the infoset and manifest. This
section, in particular, details how to create a manifest, and <a href="#wp-properties">the next</a>
lists the various properties common to infosets and manifests.</p>
</section>
<section id="wp-manifest">
<h3>Creating a Manifest</h3>
<section id="manifest-context">
<h4>Manifest Contexts</h4>
<p> A Web Publication Manifest MUST start by setting the JSON-LD context [[!json-ld]]. The context
has the following two major components:</p>
<ul>
<li>the [[!schema.org]] context: <code>https://schema.org</code></li>
<li>the Web Publication context: <code>https://www.w3.org/ns/wp-context</code></li>
</ul>
<pre class="example" title="The context declaration.">
{
"@context" : ["https://schema.org", "https://www.w3.org/ns/wp-context"],
…
}
</pre>
<p>The Web Publication context file MAY add features to the properties defined in Schema.org (e.g.,
the requirement for the <a href="https://schema.org/creator">creator</a> property to be order
preserving).</p>
<p class="note">As part of the continuous contacts with Schema.org the additional features defined
in the Web Publication context file could migrate to the core Schema.org vocabulary.</p>
<p class="note">Although Schema.org is often referenced using the <code>http</code> URI scheme, <a
href="https://schema.org/docs/faq.html#19">the vocabulary is being migrated</a> to use the
secure <code>https</code> scheme as its default. This specification requires the use
<code>https</code> when referencing Schema.org in the manifest.</p>
<p>In some cases, the context MAY be extended by additional, local information. For example, see <a
href="#language-and-dir-manifest"></a>. </p>
</section>
<section id="manifest-pub-types">
<h4>Publication Types</h4>
<p> The Web Publication Manifest MUST include a <dfn>Publication Type</dfn> using the
<code>@type</code> keyword [[!json-ld]]. The type MAY be mapped onto the <a
href="https://schema.org/CreativeWork"><code>CreativeWork</code></a>
type [[!schema.org]].</p>
<pre class="example" title="Setting a Web Publication's type to CreativeWork.">
{
"@context" : ["https://schema.org", "https://www.w3.org/ns/wp-context"],
"@type" : "CreativeWork"
…
}
</pre>
<p>Schema.org also includes a number of more specific types, all subtypes of
<code>CreativeWork</code>, such as <a href="https://schema.org/Article">Article</a>, <a
href="https://schema.org/Book">Book</a>, and <a href="https://schema.org/Course">Course</a>.
These MAY be used instead of <code>CreativeWork</code>. </p>
<pre class="example" title="Setting a Web Publication's type to Book.">
{
"@context" : ["https://schema.org", "https://www.w3.org/ns/wp-context"],
"@type" : "Book"
…
}
</pre>
<p class="note">Refer to the Schema.org site for the complete <a
href="https://schema.org/CreativeWork">list of <code>CreativeWork</code> subtypes</a>.</p>
</section>
<section id="manifest-properties">
<h3>Properties</h3>
<p>The naming, syntax, and requirements for manifest properties are defined in <a
href="#wp-properties"></a>.</p>
<p class="note">Although authors only have to understand the serialization requirements for manifest
terms, they are encouraged to read through the infoset definitions for each property, as well.
The infoset definitions describe, in some cases, how items are compiled in the absence of
explicit information in the manifest.</p>
</section>
</section>
<section id="manifest-embedding">
<h3>Embedding a Manifest</h3>
<p>A manifest can be embedded within an HTML document using the <a
href="https://www.w3.org/TR/html5/semantics-scripting.html#the-script-element"
><code>script</code> element</a> [[!html]].</p>
<p>When embedding a manifest, the <code>type</code> attribute of the containing <code>script</code>
element MUST be set to <code>application/ld+json</code>.</p>
<p>Additionally, the <code>script</code> element MUST include a unique identifier in an <code>id</code>
attribute [[!html]]. This identifier ensures that the manifest <a href="#wp-linking">can be
referenced</a>.</p>
<pre class="example" title="A Web Publication Manifest included in an HTML document">
<script id="example_manifest" type="application/ld+json">
{
…
}
</script>
</pre>
</section>
<section id="wp-linking">
<h2>Linking to a Manifest</h2>
<p>Resources SHOULD provide a link to the manifest of the Web Publication to which they belong to enable
discovery. Links MUST take one or both of the following forms:</p>
<ul>
<li><p>An HTTP <code>Link</code> header field [[!rfc5988]] with its <code>rel</code> parameter
set to the value "<code>publication</code>".</p>
<pre class="example">Link: <https://example.com/webpub/manifest>; rel=publication</pre>
</li>
<li><p>A <code>link</code> element [[!html]] with its <code>rel</code> attribute set to the
value "<code>publication</code>".</p>
<pre class="example"><link href="https://example.com/webpub/manifest" rel="publication"/></pre>
</li>
</ul>
<p>When a manifest is embedded within an HTML document, the link MUST include a fragment identifier that
references the <code>script</code> element that contains the manifest (see <a
href="#manifest-embedding"></a>). </p>
<pre class="example" title="Link to a manifest within the same HTML resource">
<link href="#example_manifest" rel="publication">
…
<script id="example_manifest" type="application/ld+json">
{
"@context" : ["https://schema.org", "https://www.w3.org/ns/wp-context"],
…
}
</script>
</pre>
<p class="issue">The exact value of <code>rel</code> is still to be agreed upon and should be registered
by IANA.</p>
<p class="ednote">The following details might be moved to the lifecycle section in a future draft.</p>
<p>When a resource links to multiple manifests, a user agent MAY choose to present one or more
alternatives to the end user, or choose a single alternative on its own. The user agent MAY choose
to present any manifest based upon information that it possesses, even one that is not explicitly
listed as a parent (e.g., based upon information it calculates or acquires out of band). In the
absence of a preference by user agent implementers, selection of the first manifest listed is
suggested as a default.</p>
</section>
<section id="wp-resources">
<h2>Resources</h2>
<p>A <a>Web Publication</a> MUST include at least one <abbr title="Hypertext Markup Language"
>HTML</abbr> document [[!html]] that <a href="#wp-linking">links to the manifest</a>. This
page is referred to as the <dfn>primary entry page</dfn> of the Web Publication.</p>
<p> The manifest may be <a href="#manifest-embedding">embedded</a> into the <a>primary entry page</a>; in
this case the link element MUST use a relative URL to refer to the manifest. </p>
<p> The manifest itself MUST NOT include a reference to itself, i.e., the reference to the manifest MUST
NOT appear as part of the <a href="#resource-categorization-properties"></a>. </p>
<p>There are no restrictions on a Web Publication beyond this requirement. The Web Publication MAY
include references to resources of any media type, both in the <a>default reading order</a> and as
dependencies of other resources.</p>
<div class="note">
<p>When adding resources to a Web Publication, consider support in user agents. The use of
progressive enhancement techniques and the provision of fallback content, as appropriate, will
ensure a more consistent reading experience for users regardless of their preferred user
agent.</p>
</div>
</section>
<section id="wp-table-of-contents">
<h3>Table of Contents</h3>
<p>The table of contents provides a hierarchical list of links that reflects the structural outline of
the major sections of the Web Publication.</p>
<p>The table of contents is expressed via an HTML element in one of the <a href="#wp-resources"
>resources</a> (typically a <code>nav</code> element [[!html]]). This element MUST be
identified by the <code>role</code> attribute [[!html]] value
"<code>doc-toc</code>" [[!dpub-aria-1.0]], and MUST be the first element in the document so
designated.</p>
<p>The table of contents SHOULD be located in the <a>primary entry page</a> of the Web Publication. If
not, the manifest SHOULD <a href="#table-of-contents-manifest">identify the resource</a> that
contains the structure.</p>
<p>There are no requirements on the table of contents itself, except that, when specified, it MUST
include a link to at least one <a href="#wp-resources">resource</a>.</p>
<p>Refer to the <a href="#table-of-contents">table of contents property definition</a> for more
information on how to identify in the infoset and manifest which resource contains the table of
contents.</p>
<p class="issue">This question arises only if the table of contents is accepted: can a table of contents
navigation element refer, via links, to any resource that is <em>not</em> listed in the <a>default
reading order</a>?</p>
</section>
</section>
<section id="wp-properties">
<h2>Web Publication Properties</h2>
<section id="properties-intro" class="informative">
<h3>Introduction</h3>
<p>Both the Web Publication infoset and manifest are defined by a common set of properties that describe
the basic information a user agent requires to process and render a Web Publication. These
properties are categorized as followed:</p>
<dl>
<dt><a href="#descriptive-properties">descriptive properties</a></dt>
<dd>
<p>Descriptive properties describe aspects of a Web Publication, such as its <a href="#title"
>title</a>, <a href="#creators">creator</a>, and <a href="#language-and-dir"
>language</a>. These properties are primarily drawn from <a href="https://schema.org"
>Schema.org</a> and its <a href="https://schema.org/docs/schemas.html">hosted
extensions</a> [[schema.org]], so they map to one or several Schema.org properties
and inherit their syntax and semantics. (The following property categories typically do not
have Schema.org equivalents, so are defined specifically for Web Publications.)</p>
</dd>
<dt><a href="#informative-properties">informative properties</a></dt>
<dd>
<p>Informative properties identify resources that contain additional information about the Web
Publication, such as its <a href="#privacy-policy">privacy policy</a> or an <a
href="#accessibility-report">accessibility report</a>.</p>
</dd>
<dt><a href="#structural-properties">structural properties</a></dt>
<dd>
<p>Structural properties identify key meta structures of the Web Publication, such as the <a
href="#cover">cover image</a> or the the location of the <a href="#table-of-contents"
>table of contents</a>.</p>
</dd>
<dt><a href="#resource-categorization-properties">resource categorization</a></dt>
<dd>
<p>Resource categorization properties describe or identify common sets of resources, such as the
<a href="#resource-list">resource list</a> and <a href="#default-reading-order">default
reading order</a>. These properties refer to one or more external resources (images,
script files, separate metadata files, etc.).</p>
</dd>
</dl>
<p class="note">The categorization of properties is done to simplify comprehension of their purpose; the
groupings have no relevance outside this specification (i.e., the groupings do not exist in the
infoset or manifest).</p>
<p class="note">Schema.org includes a large number of properties that, though relevant for publishing,
are are not mentioned in this specification; Web Publication authors can use any of those
properties. This document defines only the minimal set of infoset items, and their mapping to
Schema.org when appropriate. </p>
<p class="ednote">There are discussion on whether a best practices document would be created, referring
to more schema.org terms. If so, it should be linked from here. </p>
<p class="issue" data-number="235"></p>
</section>
<section id="wp-properties-req">
<h3>Requirements</h3>
<p>The requirements for the expression of Web Publication properties are defined by the <abbr
title="information set"><a>infoset</a></abbr> as follows:</p>
<dl>
<dt>REQUIRED:</dt>
<dd>
<ul>
<li><a href="#address">address</a></li>
<li><a href="#default-reading-order">default reading order</a></li>
<li><a href="#resource-list">resource list</a></li>
</ul>
</dd>
<dt>RECOMMENDED:</dt>
<dd>
<ul>
<li><a href="#accessibility">accessibility</a></li>
<li><a href="#accessibility-report">accessibility report</a></li>
<li><a href="#language-and-dir">base direction</a></li>
<li><a href="#canonical-identifier">canonical identifier</a></li>
<li><a href="#cover">cover</a></li>
<li><a href="#creators">creators</a></li>
<li><a href="#language-and-dir">language</a></li>
<li><a href="#links">links</a></li>
<li><a href="#last-modification-date">last modification date</a></li>
<li><a href="#publication-date">publication date</a></li>
<li><a href="#privacy-policy">privacy policy</a></li>
<li><a href="#reading-progression-direction">reading progression direction</a></li>
<li><a href="#table-of-contents">table of contents</a></li>
<li><a href="#title">title</a></li>
</ul>
</dd>
</dl>
<p>As the infoset properties do not all have to be serialized in the manifest, the requirements for the
manifest will differ in some cases. Refer to each property's definition to determine whether it is
required in the manifest or can be compiled from other information.</p>
</section>
<section id="properties-linked">
<h3>Link Values</h3>
<p>With the exception of the <a href="#descriptive-properties">descriptive properties</a>, the Web
Publication properties typically link to one or more resources. When a property requires a link
value, the link MUST be expressed in one of the following two ways:</p>
<ol>
<li>as a string encoding the (absolute or relative) URL of the resources [[!url]]; or</li>
<li>as an instance of a <a href="#publication-link-def"><code>PublicationLink</code> object</a> that
can be used to express the URL, the media type, and other characteristics of the target
resource.</li>
</ol>
<pre class="example" title="Resource list includes one link using a string value ('datatypes.svg') and two that display the various properties of the a PublicationLink object">
{
…
"resources" : [
"datatypes.svg",
{
"@type" : "PublicationLink",
"url" : "test-utf8.csv",
"fileFormat" : "text/csv",
"name" : "Test Results",
"description" : "CSV file containing the full data set used in this research."
},
{
"@type" : "PublicationLink",
"url" : "terminology.html",
"fileFormat" : "text/html",
"rel" : "glossary"
}
]
}
</pre>
<section id="publicationLink">
<h2><code>PublicationLink</code> Definition</h2>
<p id="publication-link-def">This specification defines a new type for links called
<code>PublicationLink</code>. It consists of the following properties:</p>
<table class="zebra">
<thead>
<tr>
<th>Term</th>
<th>Description</th>
<th>Required Value</th>
<th>[[!schema.org]] Mapping</th>
<th>Optionality</th>
</tr>
</thead>
<tbody>
<tr>
<td>
<code>url</code>
</td>
<td>Location of the resource.</td>
<td>A URL [[!url]]. Refer to the property definitions that accept this type for
additional restrictions.</td>
<td>
<a href="https://schema.org/url"><code>url</code></a>
</td>
<td>REQUIRED</td>
</tr>
<tr>
<td>
<code>fileFormat</code>
</td>
<td>Media type of the resource (e.g., <code>text/html</code>).</td>
<td>MIME Media Type [[!rfc2046]].</td>
<td>
<a href="https://schema.org/fileFormat"><code>fileFormat</code></a>
</td>
<td>OPTIONAL</td>
</tr>
<tr>
<td>
<code>name</code>
</td>
<td>Name of the item.</td>
<td>Text.</td>
<td>
<a href="https://schema.org/name"><code>name</code></a>
</td>
<td>OPTIONAL</td>
</tr>
<tr>
<td>
<code>description</code>
</td>
<td>Description of the item.</td>
<td>Text.</td>
<td>
<a href="https://schema.org/description"><code>description</code></a>
</td>
<td>OPTIONAL</td>
</tr>
<tr>
<td>
<code>rel</code>
</td>
<td>The relationship of the resource to the Web Publication.</td>
<td>
<p>One or more relations. The values are either the relevant relationship terms of
the IANA link registry [[!iana-link-relations]], or specially-defined URLs
if no suitable link registry item exists.</p>
</td>
<td>(None)</td>
<td>OPTIONAL</td>
</tr>
</tbody>
</table>
</section>
</section>
<section id="descriptive-properties">
<h3>Descriptive Properties</h3>
<section id="accessibility">
<h4>Accessibility</h4>
<p>The accessibility properties provides information about the suitability of a <a>Web
Publication</a> for consumption by users with varying preferred reading modalities. These
properties typically supplement an evaluation against established accessibility criteria, such
as those provided in [[WCAG20]]. (For linking to a detailed accessibility report, see <a
href="#accessibility-report"></a>.)</p>
<section id="accessibility-infoset">
<h5>Infoset Requirements</h5>
<p>The following infoset items are categorized as accessibility properties:</p>
<ul>
<li>accessMode</li>
<li>accessModeSufficient</li>
<li>accessibilityAPI</li>
<li>accessibilityControl</li>
<li>accessibilityFeature</li>
<li>accessibilityHazard</li>
<li>accessibilitySummary</li>
</ul>
<p class="note">More detailed descriptions of these properties, as well as the possible values,
are described on the <a href="http://www.w3.org/wiki/WebSchemas/Accessibility">WebSchemas
Wiki site</a>.</p>
</section>
<section id="accessibility-manifest">
<h5>Manifest Expression</h5>
<table class="zebra">
<thead>
<tr>
<th>Term</th>
<th>Description</th>
<th>Required Value</th>
<th>[[!schema.org]] Mapping</th>
</tr>
</thead>
<tbody>
<tr>
<td>
<code>accessMode</code>
</td>
<td> The human sensory perceptual system or cognitive faculty through which a person
may process or perceive information. </td>
<td> Text. <a
href="https://www.w3.org/wiki/WebSchemas/Accessibility#accessibilityFeature_in_detail"
>Expected values</a>. </td>
<td>
<a href="http://meta.schema.org/accessMode"><code>accessMode</code></a>
</td>
</tr>
<tr>
<td>
<code>accessModeSufficient</code>
</td>
<td> A list of single or combined accessModes that are sufficient to understand all
the intellectual content of a resource. </td>
<td> Comma-separated values. <a
href="https://www.w3.org/wiki/WebSchemas/Accessibility#accessibilityFeature_in_detail"
>Expected values</a>. </td>
<td>
<a href="http://meta.schema.org/accessModeSufficient"
><code>accessModeSufficient</code></a>
</td>
</tr>
<tr>
<td>
<code>accessibilityAPI</code>
</td>
<td> Indicates that the resource is compatible with the referenced accessibility
API. </td>
<td> Text. <a
href="https://www.w3.org/wiki/WebSchemas/Accessibility#accessibilityFeature_in_detail"
>Expected values</a>. </td>
<td>
<a href="https://schema.org/accessibilityAPI"><code>accessibilityAPI</code></a>
</td>
</tr>
<tr>
<td>
<code>accessibilityControl</code>
</td>
<td> Identifies input methods that are sufficient to fully control the described
resource. </td>
<td> Text. <a
href="https://www.w3.org/wiki/WebSchemas/Accessibility#accessibilityFeature_in_detail"
>Expected values</a>. </td>
<td>
<a href="http://meta.schema.org/accessibilityControl"
><code>accessibilityControl</code></a>
</td>
</tr>
<tr>
<td>
<code>accessibilityFeature</code>
</td>
<td> Content features of the resource, such as accessible media, alternatives and
supported enhancements for accessibility. </td>
<td> Text. <a
href="https://www.w3.org/wiki/WebSchemas/Accessibility#accessibilityFeature_in_detail"
>Expected values</a>. </td>
<td>
<a href="http://meta.schema.org/accessibilityFeature"
><code>accessibilityFeature</code></a>
</td>
</tr>
<tr>
<td>
<code>accessibilityHazard</code>
</td>
<td> A characteristic of the described resource that is physiologically dangerous to
some users. </td>
<td> Text. <a
href="https://www.w3.org/wiki/WebSchemas/Accessibility#accessibilityFeature_in_detail"
>Expected values</a>. </td>
<td>
<a href="http://meta.schema.org/accessibilityHazard"
><code>accessibilityHazard</code></a>
</td>
</tr>
<tr>
<td>
<code>accessibilitySummary</code>
</td>
<td>A human-readable summary of specific accessibility features or deficiencies,
consistent with the other accessibility metadata but expressing subtleties such
as “short descriptions are present but long descriptions will be needed for
non-visual users” or “short descriptions are present and no long descriptions
are needed.” </td>
<td>Text.</td>
<td>
<a href="http://meta.schema.org/accessibilitySummary"
><code>accessibilitySummary</code></a>
</td>
</tr>
</tbody>
</table>
<p>Note that the author MAY also provide a reference to a more detailed <a
href="#accessibility-report-manifest">Accessibility Report</a>, beyond the accessibility
information expressed by these properties.</p>
<pre class="example" title="Example for accessiblity metadata of a purely textual document">
{
"@context" : ["https://schema.org","https://www.w3.org/ns/wp-context"],
"@type" : "CreativeWork",
…
"accessMode" : ["textual", "visual"],
"accessModeSufficient" : ["textual"],
…
}
</pre>
</section>
</section>
<section id="address">
<h4>Address</h4>
<p>A <a>Web Publication's</a>
<dfn>address</dfn> is a <abbr title="Uniform Resource Locator">URL</abbr> [[!url]] that
represents the <a>primary entry page</a> for the Web Publication.</p>
<section id="address-infoset">
<h5>Infoset Requirements</h5>
<p>The referenced document SHOULD be a resource of the Web Publication. It can be any resource,
including one that is not listed in the <a>default reading order</a>. This document MUST
include a <a href="#wp-linking">link to the manifest</a> to ensure a bidirectional linking
relationship (i.e., that user agents can also locate the manifest from the document at the
address.</p>
<p>If the canonical URL does not resolve to an <abbr title="Hypertext Markup Language"
>HTML</abbr> document [[!html]], user agents SHOULD NOT provide access to it to
users.</p>
<p>If the document is not a Web Publication resource, user agents SHOULD load the first document
in the <a>default reading order</a> when initiating the Web Publication.</p>
<p class="note">To improve the usability of Web Publications, particularly in user agents that
do not support Web Publications, include navigation aids in the referenced document that
facilitate consumption of the content, (e.g., provide a table of contents or a link to
one).</p>
<p>The availability of the address does not preclude the creation and use of other identifiers
and/or addresses to retrieve a <a>Web Publication</a>, whether in whole or in part.</p>
<div class="note">The Web Publication's address can also be used as value for an identifier link
relation [[link-relation]].</div>
</section>
<section id="address-manifest">
<h5>Manifest Expression</h5>
<table class="zebra">
<thead>
<tr>
<th>Term</th>
<th>Description</th>
<th>Required Value</th>
<th>[[!schema.org]] Mapping</th>
</tr>
</thead>
<tbody>
<tr>
<td>
<code>url</code>
</td>
<td>URL of the primary entry page.</td>
<td>A URL [[!url]].</td>
<td>
<a href="https://schema.org/url"><code>url</code></a>
</td>
</tr>
</tbody>
</table>
<pre class="example" title="Setting the address of the main entry page">
{
"@context" : ["https://schema.org","https://www.w3.org/ns/wp-context"],
"@type" : "Book",
…
"url" : "https://publisher.example.org/mobydick",
…
}
</pre>
</section>
</section>
<section id="canonical-identifier">
<h4>Canonical Identifier</h4>
<p>A <a>Web Publication's</a>
<dfn>canonical identifier</dfn> is a unique identifier that resolves to the preferred version of
the Web Publication.</p>
<section id="canonical-identifier-infoset">
<h5>Infoset Requirements</h5>
<p>The canonical identifier MUST be an <a>address</a>.</p>
<p>If a Web Publication is hosted at multiple addresses, the canonical identifier allows a user
agent to identify the shared relationship between the versions and to determine which of the
available addresses is primary.</p>
<p>The canonical identifier is also intended to provide a measure of permanence above and beyond
the Web Publication's <a>address</a>. Even if a Web Publication is permanently relocated to
a new address, for example, the canonical identifier will provide a way of locating the new
location (e.g., a <abbr title="Digital Object Identifier">DOI</abbr> registry could be
updated with the new <abbr title="Uniform Resource Locator">URL</abbr>, or a redirect could
be added to the <abbr title="Uniform Resource Locator">URL</abbr> of the canonical
identifier).</p>
<p>When assigned, the canonical identifier needs to be unique to one and only one Web
Publication, independent of its address(es). Ensuring uniqueness is outside the scope of
this specification, however. The actual uniqueness achievable depends on such factors as the
conventions of the identifier scheme used and the degree of control over assignment of
identifiers.</p>
<p>If a URL is not provided in the manifest, or the value is an invalid URL, the Web Publication
does not have a canonical identifier. In this case, a user agent MUST NOT make any
assumptions about the relationship between the current Web Publication and any other
possible versions of it (i.e., treat each instance as unique).</p>
<p class="note">The canonical identifier can be used as the target of a "canonical"
link [[rfc6596]] (e.g., a <code>link</code> element [[html]] whose
<code>rel</code> attribute has the value <code>canonical</code> or an <abbr
title="Hypertext Transfer Protocol">HTTP</abbr>
<code>Link</code> header field [[rfc5988]] similarly identified).</p>
<p class="issue" data-number="58">Is a canonical identifier necessary to call out explicitly in
the <abbr title="information set">infoset</abbr>, or can it be handled by other
metadata.</p>
</section>
<section id="canonical-identifier-manifest">
<h5>Manifest Expression</h5>
<table class="zebra">
<thead>
<tr>
<th>Term</th>
<th>Description</th>
<th>Required Value</th>
<th>[[!schema.org]] Mapping</th>
</tr>
</thead>
<tbody>