LISTSERV mailing list manager LISTSERV 16.5

Help for CODE4LIB Archives


CODE4LIB Archives

CODE4LIB Archives


CODE4LIB@LISTS.CLIR.ORG


View:

Message:

[

First

|

Previous

|

Next

|

Last

]

By Topic:

[

First

|

Previous

|

Next

|

Last

]

By Author:

[

First

|

Previous

|

Next

|

Last

]

Font:

Proportional Font

LISTSERV Archives

LISTSERV Archives

CODE4LIB Home

CODE4LIB Home

CODE4LIB  January 2013

CODE4LIB January 2013

Subject:

metadata vocab re-use question?

From:

Jonathan Rochkind <[log in to unmask]>

Reply-To:

Code for Libraries <[log in to unmask]>

Date:

Tue, 29 Jan 2013 15:22:38 -0500

Content-Type:

text/plain

Parts/Attachments:

Parts/Attachments

text/plain (134 lines)

Hello fine code4libbers, I have a technical question about metadata 
vocab reuse, and the best way to do something I'm doing.

I'm working on an API for returning a list of scholarly articles.

I am trying to do as much as I can with already existing technical 
metadata devices.

In general, I am going to do this as an Atom XML response, with some 
'third party' XML namespaces in use too for full expression of what I 
want to express.  Using already existing vocabularies, identified by URI.

In general, this is working fine -- especially using the PRISM 
vocabulary for some scholarly citation-specific metadata elements. Also 
some things that were already part of Atom, and may be a bit of DC here 
or there.

I am generally happy with this approach, and plan to stick to it.

But there are a few places where I am not sure what to do. In general, 
there's a common pattern where I need to express a certain 'element' 
using _multiple_ vocabularies simultaneously (and/or no vocabulary at 
all, free text).

For instance, let's take the (semantically vague, yes) concept of 
type/genre.  I have a schema.org type URI that expresses the 'type'.  I 
can _also_ express the 'type' using the dcterms 'type' vocabulary. I 
could theoretically have a couple more format/type vocabularies I'd like 
to expose, but let's stop there as an example. And on top of this, I 
_also_ have a free text 'type' string (which may or may not be derivable 
from the controlled vocabs), which I'd like to make available to API 
consumer too.

Any individual item may have some, all, or none of these data associated 
with it.

Now, the dcterms 'type' element is capable of holding any or all of 
these. http://dublincore.org/documents/dcmi-terms/#terms-type

"Recommended best practice is to use a controlled vocabulary such as the 
DCMI Type Vocabulary [DCMITYPE]. To describe the file format, physical 
medium, or dimensions of the resource, use the Format element."

See, _recommended_ is to use a controlled vocab _such as_ DCMI Type 
Vocab, but this makes it clear you can also use the 'type' element for 
another controlled vocab, or no controlled vocab at all.

So it's _legal_ to simply do something like this:

<!-- schema.org: -->
<dcterms:type>http://schema.org/ScholarlyArticle</dcterms:type>

<!-- dcterms type vocab: -->
<dcterms:type>http://purl.org/dc/dcmitype/Text</dcterms:type>

<!-- free text not from a controlled vocab: -->
<dcterms:type>Scholarly Book Review</dcterms:type>



And I've been the _consumer_ of API's which do something like that: Just 
throw a grab bag of differnet things into repeated dcterms:type 
elements, including URIs representing values from different vocabs, and 
free text.  They figure, hey, it's legal to use dcterms:type that way 
according to the docs for the dcterms vocab.

And as a consumer of services that do that... I do not want to do it. It 
is too difficult to work with as a consumer, when you don't know what 
the contents of a dcterms:type element might be, from any vocab, or none 
at all. It kind of ruins the utility of the controlled vocabs in the 
first place, or requires unreasonably complex logic on the client side.

So. Another idea that occurs is just to add some custom attributes to 
the dcterms:type element.

<dcterms:type 
vocab="schema.org">http://schema.org/ScholarlyArticle</dcterms:type>
<dcterms:type 
vocab="dcterms">http://purl.org/dc/dcmitype/Text</dcterms:type>
<dcterms:type>Scholarly Book Review</dcterms:type>

Now at least the client can a lot more easily write logic for "Is there 
a dcterms value? If so what is it.

But I can't really tell if this is legal or not -- attributes are 
handled kind of inconsistently by various XML validators. Maybe I'd need 
to namespace the attribute with a custom namespace too:

... xmlns:mine=http://example.org/vocab ...

<dcterms:type 
mine:vocab="schema.org">http://schema.org/ScholarlyArticle</dcterms:type>

But namespaces on attributes are handled _very_ inconsistently and 
buggily by various standard XML parsing libraries I've used, so I don't 
really want to do that, it's going to make things too hard on the client 
to use namespaced attributes.

But I kind of like the elegancy of that 'add attributes to dcterms:type' 
approach. I suppose you could even use full URIs instead of random terms 
to identify the vocab, for the elegance of it:

<dcterms:type 
vocab="http://schema.org">http://schema.org/ScholarlyArticle</dcterms:type>
<dcterms:type 
vocab="http://dublincore.org/documents/dcmi-terms">http://purl.org/dc/dcmitype/Text</dcterms:type>

But another option, especially if that isn't legal,  is to give up 
dcterms entirely and use only my own custom namespace/vocab for 'type' 
elements:

<mine:schema-type>http://schema.org/ScholarlyArticle</dcterms:type>
<mine:dcterms-type>http://purl.org/dc/dcmitype/Text</dcterms:type>
<mine:uncontrolled-type>Scholarly Book Review</dcterms:type>


Which is kind of 'inelegant', but would probably work fine too. 
Realistically, any consumer of my response is going to be custom written 
for my response, it can be written to deal with mine:schema-type just as 
well as dcterms:type with attribute vocab=something.  Standardizing here 
isn't really _neccesary_ at all for primary use cases, although there 
are a variety of anxilary hypothetical benefits.

Or maybe there's some other solution entirely I'm not thinking of.

So, any feedback?  What solution makes sense, balancing standards, 
clarity, parsimony, ease of development, ease of client development, etc.?

The 'type' example is a good example, but this comes up in some other 
places too. Another example is for 'language', I may have either or both 
of an ISO code (two letter or three letter variety, such as "en" or 
"eng"), and an English-language free text description of the language 
"English", and want to provide either one or both, unambiguously and 
easy to consume for the client.

Top of Message | Previous Page | Permalink

Advanced Options


Options

Log In

Log In

Get Password

Get Password


Search Archives

Search Archives


Subscribe or Unsubscribe

Subscribe or Unsubscribe


Archives

February 2019
January 2019
December 2018
November 2018
October 2018
September 2018
August 2018
July 2018
June 2018
May 2018
April 2018
March 2018
February 2018
January 2018
December 2017
November 2017
October 2017
September 2017
August 2017
July 2017
June 2017
May 2017
April 2017
March 2017
February 2017
January 2017
December 2016
November 2016
October 2016
September 2016
August 2016
July 2016
June 2016
May 2016
April 2016
March 2016
February 2016
January 2016
December 2015
November 2015
October 2015
September 2015
August 2015
July 2015
June 2015
May 2015
April 2015
March 2015
February 2015
January 2015
December 2014
November 2014
October 2014
September 2014
August 2014
July 2014
June 2014
May 2014
April 2014
March 2014
February 2014
January 2014
December 2013
November 2013
October 2013
September 2013
August 2013
July 2013
June 2013
May 2013
April 2013
March 2013
February 2013
January 2013
December 2012
November 2012
October 2012
September 2012
August 2012
July 2012
June 2012
May 2012
April 2012
March 2012
February 2012
January 2012
December 2011
November 2011
October 2011
September 2011
August 2011
July 2011
June 2011
May 2011
April 2011
March 2011
February 2011
January 2011
December 2010
November 2010
October 2010
September 2010
August 2010
July 2010
June 2010
May 2010
April 2010
March 2010
February 2010
January 2010
December 2009
November 2009
October 2009
September 2009
August 2009
July 2009
June 2009
May 2009
April 2009
March 2009
February 2009
January 2009
December 2008
November 2008
October 2008
September 2008
August 2008
July 2008
June 2008
May 2008
April 2008
March 2008
February 2008
January 2008
December 2007
November 2007
October 2007
September 2007
August 2007
July 2007
June 2007
May 2007
April 2007
March 2007
February 2007
January 2007
December 2006
November 2006
October 2006
September 2006
August 2006
July 2006
June 2006
May 2006
April 2006
March 2006
February 2006
January 2006
December 2005
November 2005
October 2005
September 2005
August 2005
July 2005
June 2005
May 2005
April 2005
March 2005
February 2005
January 2005
December 2004
November 2004
October 2004
September 2004
August 2004
July 2004
June 2004
May 2004
April 2004
March 2004
February 2004
January 2004
December 2003
November 2003

ATOM RSS1 RSS2



LISTS.CLIR.ORG

CataList Email List Search Powered by the LISTSERV Email List Manager