Bug 22520

Summary: [HTML]:
Product: HTML WG Reporter: Andrea Rendine <master.skywalker.88>
Component: HTML5 specAssignee: This bug has no owner yet - up for the taking <dave.null>
Status: RESOLVED FIXED QA Contact: HTML WG Bugzilla archive list <public-html-bugzilla>
Severity: normal    
Priority: P2 CC: mike, public-html-admin, public-html-wg-issue-tracking
Version: unspecified   
Target Milestone: ---   
Hardware: PC   
OS: All   
Whiteboard:

Description Andrea Rendine 2013-06-29 21:02:18 UTC
"Link types" - Insert "schema.DCTERMS" and "schema.DC" among the allowed < rel> attribute values, according to the Dublin Core Metadata specification <http://dublincore.org/documents/dc-html/>, along with the DCTERMS.[element] and DC.[element] statements. This would allow a correct usage of the <meta name="dcterms.[element]" ...> meta tag. 
These meta names are proposed in the MetaExtension WikiWHATWG page, but according to the DCMI reference, such indications are useless because the name "dcterms.[element]" does not compose a reference URI considered stand-alone. 

It would provide an easy, complete and standard-compliant way of indicating useful metadata, included but not limited to, validity of a document and last modification. Otherwise, provide a standard implied reference for metadata defined with "dcterms" and "dc" prefix literals, which is explicitly excluded by the mentioned reference.
Comment 1 Michael[tm] Smith 2013-06-30 03:02:35 UTC
(In reply to comment #0)
> These meta names are proposed in the MetaExtension WikiWHATWG page, but
> according to the DCMI reference, such indications are useless because the
> name "dcterms.[element]" does not compose a reference URI considered
> stand-alone. 

What does that mean?
Comment 2 Andrea Rendine 2013-06-30 10:17:06 UTC
(In reply to comment #1)
> What does that mean?

Quotes from Dublin Core:
 "The DCAM uses Uniform Resource Identifiers (URIs) [RFC3986] to refer both to the resources described and to metadata terms (properties, classes, vocabulary encoding schemes and syntax encoding schemes). In the DC-HTML profile, those URIs are encoded as X/HTML attribute values."
  "In DC-HTML, property URIs and syntax encoding scheme URIs are represented as DC-HTML Prefixed Names. A DC-HTML Prefixed Name is an abbreviation for a URI used in the DC-HTML format. A DC-HTML Prefixed Name consists of a "prefix" followed by a period (".") and a "local name"."
 "The "prefix" in a DC-HTML Prefixed Name is associated with a "namespace URI" using a namespace declaration, made using a Namespace Declaration Element. The URI represented by the DC-HTML Prefixed Name is determined by concatenating the "namespace URI" with which the prefix is associated and the "local name"."
 "A DC-HTML namespace declaration associates a URI with a prefix, so that when that prefix is used in a DC-HTML Prefixed Name, that URI is used as a "namespace URI". A namespace declaration is made using the X/HTML link element and a specific convention for the value of the rel attribute. In the DC-HTML profile, an X/HTML link element of which the rel attribute has a value beginning with the characters schema. represents a namespace declaration. The DC-HTML namespace declaration must include:
 - a prefix, represented by part of the value of the rel attribute of the X/HTML link element following the characters schema.
 - a namespace URI, represented by the value of the href attribute of the X/HTML link element"
 "In the DC-HTML profile, a property URI in a statement containing a literal values surrogate is represented as a DC-HTML Prefixed Name which is the value of the name attribute of an X/HTML meta element."
For a complete reference and examples, though dated, see "Expressing Dublin Core metadata using HTML/XHTML meta and link elements" <http://dublincore.org/documents/dc-html/>
Comment 3 Andrea Rendine 2013-06-30 20:02:45 UTC
Addendum: in short, in order to use DCTERMS metadata (http://wiki.whatwg.org/wiki/MetaExtensions), the list of allowed <link rel=""> values must be updated including at least the conventional namespace abbreviation "schema.DCTERMS", possibly along with the "schema.DC". 
The metadata description set model for HTML should be corrected as follows:

code:
<link rel="schema.DCTERMS" href="http://purl.org/dc/terms/" />
<meta name="DCTERMS.[element]" value="[elementValue]" />
(http://dublincore.org/documents/dc-html/)

If the prefix used in a DC-HTML Prefixed Name has not been associated with a URI in a namespace declaration, no URI can be generated for that DC-HTML Prefixed Name [...] (if) there are no namespace declarations for those prefixes ... no URI is generated for those values of the name attribute of the meta element. [...] the "DC" and "DCTERMS" prefixes are not subject to any special treatment; there are no "built-in" namespace declarations.
Comment 4 Michael[tm] Smith 2013-07-01 01:32:03 UTC
(In reply to comment #3)
> Addendum: in short, in order to use DCTERMS metadata
> (http://wiki.whatwg.org/wiki/MetaExtensions), the list of allowed <link
> rel=""> values must be updated including at least the conventional namespace
> abbreviation "schema.DCTERMS", possibly along with the "schema.DC". 

See http://microformats.org/wiki/existing-rel-values#unspecified
Comment 5 Andrea Rendine 2013-07-01 11:31:55 UTC
(In reply to comment #4)
> (In reply to comment #3)
> > Addendum: in short, in order to use DCTERMS metadata
> > (http://wiki.whatwg.org/wiki/MetaExtensions), the list of allowed <link
> > rel=""> values must be updated including at least the conventional namespace
> > abbreviation "schema.DCTERMS", possibly along with the "schema.DC". 
> 
> See http://microformats.org/wiki/existing-rel-values#unspecified

Read in detail. Following this answer I also read the linked public discussion on Microformats.org until the message http://microformats.org/discuss/mail/microformats-discuss/2008-January/011452.html. So what are the conclusions?
Comment 6 Michael[tm] Smith 2013-07-01 13:30:22 UTC
(In reply to comment #5)
> (In reply to comment #4)
> > (In reply to comment #3)
> > > Addendum: in short, in order to use DCTERMS metadata
> > > (http://wiki.whatwg.org/wiki/MetaExtensions), the list of allowed <link
> > > rel=""> values must be updated including at least the conventional namespace
> > > abbreviation "schema.DCTERMS", possibly along with the "schema.DC". 
> > 
> > See http://microformats.org/wiki/existing-rel-values#unspecified
> 
> Read in detail. Following this answer I also read the linked public
> discussion on Microformats.org until the message
> http://microformats.org/discuss/mail/microformats-discuss/2008-January/
> 011452.html. So what are the conclusions?

I'm not sure what the conclusions are but I've gone ahead and added support for link@rel=schema.dc and link@rel=schema.dcterms anyway. Please test it and if you find anything wrong, feel free to reopen this bug or post a new one.

http://validator.w3.org/nu/