This is a pilot release of the NSDL-LONCAPA Gateway.
Implement a metadata exchange of resources from
NSDL (http://www.smete.org) to LON-CAPA (http://www.lon-capa.org)
and vice versa.
More information is in the doc/ directory.
Quick installation instructions
If you are using a tarball, then, as root, execute the UPDATE command:
If you are working directly from the CVS repository, then, as root:
cd build; make build; make install.
For a history of this software, you should work through
the CVS repository.
cvs co nsdl
How to build and install
To get a good overview on the metadata conversion, I recommend
you look at the nsdl/prototypes/metadata_convert.pl script
(perldoc ./metadata_convert.pl). Among other things, this
provides a list regarding the crosswalk possibilities of
LON-CAPA to&from IEEE-LOM and LON-CAPA to&from Dublin Core.
Currenty, the four stylesheets for carrying out the metadata conversion are:
The Apache web handler modules are defined in the directory:
The Apache configuration file (see below also) is
The source-to-target information is defined by nsdl/build/gatewayfiles.lpml
(an XML file defines how the software is "rendered" onto the system).
gatewayfiles.lpml is used in many locations inside nsdl/build/Makefile.
And, there are other files.
* Apache and mod_perl
* Graham Barr's TimeDate module (http://search.cpan.org/search?dist=TimeDate)
* XML::Xalan perl module (http://search.cpan.org/search?dist=XML-Xalan)
To configure your machine, you will need to add the following
line to your /etc/httpd/conf/httpd.conf file.
(You will then need to restart your web server;
This is a pilot effort. The goal was to enact a reasonable
solution and directly uncover difficult issues.
Here are some of the remaining issues
* ISSUE: User authentication
PROBLEM: users are crossing domains, so browser-cookie validation can't work
SUGGESTED SOLUTIONS: should require a GPG public key and/or
servers should communicate to coordinate passing of user
and/or some kind of proxy or central verification system
* ISSUE: Imperfect metadata cross-walking
PROBLEM: There are a range of imperfect mappings between Dublin Core and
LON-CAPA metadata fields as well as between IEEE LOM and LON-CAPA
SUGGESTED SOLUTIONS: Improve the LON-CAPA metadata that is collected and
place more importance on the exhaustive IEEE LOM
standard rather than the weaker Dublin Core standard.
In the future, to get to Dublin Core, it might make
sense to first convert LON-CAPA to IEEE LOM and *then*
go to the Dublin Core metadata standard.
* ISSUE: Set hierarchies
PROBLEM: Asking for ListIdentifiers from LON-CAPA will return a really long
list that represents a "jumbled" repository. Currently,
ListIdentifiers, ListRecords, etc return error messages--
we do not yet support set hierarchy results.
SUGGESTED SOLUTIONS: authors should be able to nominate their records
for being part of a meaningful collection of academic
resources; thus multiple OAI-distributed metadata sets
would actually be contained within LON-CAPA
* ISSUE: Code thoroughness
PROBLEM: Limited time. I had limited time (100 hours) to enact a gateway.
SUGGESTED SOLUTIONS: Invest more time. The API and documentation
could be a better match for what is implemented
and vice versa.
* ISSUE: Making SMETE available to LON-CAPA
PROBLEM: Ummm... I thought SMETE supported OAI. The only interface I find
is enriched HTML forms.
SUGGESTED SOLUTIONS: SMETE should support OAI or some exporting of XML files
in Dublin Core or IEEE LOM or whatever they are using.
Scott Harrison, 2002