On Wed, 23 Jul 2003, Julian Reschke wrote:
> we're currently working on extracing data from HTML based on RFC2731. The
> main issues we encountered so far are:
I'm not sure that you'll get any firm answers to these questions... but
I'll give you my personal thoughts.
> - when processing the HEAD part, is ordering of LINK and META tags relevant?
> Is it ok if the link element mapping the schema prefix to a URI occurs
> *after* the META tag using it? What is the scope? Is it allowed to have
> multiple link elements that map the same prefix to different URIs?
I would think that the ordering in not significant - and that therefore
you should not have multiple link elements that map the same prefix to
different URIs.
> - uppercase/lowercase: similar to WebDAV (RFC2518), our system identifies
> properties based on a namespace name (URI reference) and a local name (XML
> element name). In WebDAV, case *is* relevant. What's the convention for DCMI
> properties?
The convention in HTML has tended to be for element names to start with an
uppercase letter (DC.Title). In other syntaxes (i.e. XML and RDF/XML)
that make proper use of XML namespaces, all element names start with a
lowercase letter (dc:title). That's why in the draft DC/HTML
recommendation at
http://www.ukoln.ac.uk/metadata/dcmi/dcq-html/
I recommend that applications should always generate lowercase first
letters, but accept letters in any (mixed) case.
> - assuming that I'd want to use RFC2731-style encoding to map *arbitrary*
> properties into my own (case-sensitive) property schema -- is there any
> reliable way to find out whether for a given scheme (such as
> "http://purl.org/DC/elements/1.0/") case is relevant or not?
>
> - versioning: do "http://purl.org/DC/elements/1.0/" (RFC2731),
> "http://purl.org/dc/elements/1.1/"
> (<http://www.ukoln.ac.uk/metadata/dcmi/dcq-html/>) and "http://purl.org/dc"
> (example usage in the W3C home page) identify the same property schemas?
http://purl.org/dc/elements/1.1/
is the namespace URI for version 1.1 of the DC elements.
I'm not sure what the other two URIs you give actually define. However,
my feeling is that the semantics of the 15 DC elements changed
sufficiently little between version 1.0 and version 1.1 that you can
reasonably treat the 3 URIs you cite above as being equivalent in the
context of HTML link tags.
Regards,
Andy
--
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