Metadata links (EPUB parsing)

[danielweck]

How should we parse <link rel="cc:license" href="http://creativecommons.org/licenses/by-sa/3.0/"/> (for example).

What is the JSON Schema equivalent?
https://github.com/readium/webpub-manifest/blob/master/schema/metadata.schema.json

Complete OPF example (note the <link rel="cc:license" refines="#cover" ... />):
https://github.com/IDPF/epub3-samples/blob/master/30/wasteland/EPUB/wasteland.opf

<?xml version="1.0" encoding="UTF-8"?>
<package xmlns="http://www.idpf.org/2007/opf" version="3.0" unique-identifier="uid" xml:lang="en-US" prefix="cc: http://creativecommons.org/ns#">
    <metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
        <dc:identifier id="uid">code.google.com.epub-samples.wasteland-basic</dc:identifier>
        <dc:title>The Waste Land</dc:title>
        <dc:creator>T.S. Eliot</dc:creator>
        <dc:language>en-US</dc:language>
        <dc:date>2011-09-01</dc:date>
        <meta property="dcterms:modified">2012-01-18T12:47:00Z</meta>
        <!-- rights expressions for the work as a whole -->
        <dc:rights>This work is shared with the public using the Attribution-ShareAlike 3.0 Unported (CC BY-SA 3.0) license.</dc:rights>        
        <link rel="cc:license" href="http://creativecommons.org/licenses/by-sa/3.0/"/>
        <meta property="cc:attributionURL">http://code.google.com/p/epub-samples/</meta>
        <!-- rights expression for the cover image -->       
        <link rel="cc:license" refines="#cover" href="http://creativecommons.org/licenses/by-sa/3.0/" />
        <link rel="cc:attributionURL" refines="#cover" href="http://en.wikipedia.org/wiki/Simon_Fieldhouse" />        
        <!-- cover meta element included for 2.0 reading system compatibility: -->
        <meta name="cover" content="cover"/>
    </metadata> 
    <manifest>
        <item id="t1" href="wasteland-content.xhtml" media-type="application/xhtml+xml" />
        <item id="nav" href="wasteland-nav.xhtml" properties="nav" media-type="application/xhtml+xml" />
        <item id="cover" href="wasteland-cover.jpg" media-type="image/jpeg" properties="cover-image" />
        <item id="css" href="wasteland.css" media-type="text/css" />
        <item id="css-night" href="wasteland-night.css" media-type="text/css" />
        <!-- ncx included for 2.0 reading system compatibility: -->
        <item id="ncx" href="wasteland.ncx" media-type="application/x-dtbncx+xml" />
    </manifest>
    <spine toc="ncx">
        <itemref idref="t1" />        
    </spine>    
</package>

Related issue: readium/r2-shared-js#16

[danielweck]

The parser doc should be updated too:
https://github.com/readium/architecture/blob/master/streamer/parser/metadata.md

[HadrienGardeur]

For <link rel="cc:license" href="http://creativecommons.org/licenses/by-sa/3.0/"/> we could do the following:

• add a Link Object in links
• extend the rel into a full URI: http://creativecommons.org/ns#license

refines is the problematic part, we don't really have the ability to support this on every metadata or resource listed in the publication.
We can refine a contributor, a publisher, a collection or a series, but we can't do this on resources listed readingOrder or resources.