oai pmh

What is OAI-PMH and where to find information?

The Open Archives Initiative - Prototcol for Metadata Harvesting provides an application-independent interoperability framework. An Interface must be able to return metadata manifestation as Dublin Core format. Optionally, a repository may also disseminate other formats of metadata. In our oerhub.at LOM format is used!

The details can be found: http://www.openarchives.org

Online Validation

Useful online tool for validation: https://validator.oaipmh.com/

Hint: The Standard says "The Content-Type returned for all OAI-PMH requests must be text/xml, but the validator expect application/xml!

LOM

The Learning Object Metadata is a data model, usually encoded in XML, used to describe a learning object and similar digital resources used to support learning.

The specification by UIBK.

Example Requests

• ListRecords - To get the List of Resourses.
  https://oer-repo.uibk.ac.at/edu-sharing/eduservlet/oai/provider?verb=ListRecords&metadataPrefix=lom.
  If a resumptionToken is present you have to iterate as long as no resunptenToken is shown
  https://www.zoerr.de/edu-sharing/eduservlet/oai/provider?verb=ListRecords&metadataPrefix=hs_oer_lom,
  An example for the iteration over the list
  https://www.zoerr.de/edu-sharing/eduservlet/oai/provider?verb=ListRecords&resumptionToken=MTozMDB8Mjp8Mzp8NDp8NTpoc19vZXJfbG9t

• GetRecord - To get the Details of a specific Resourse:
  https://oer-repo.uibk.ac.at/edu-sharing/eduservlet/oai/provider?verb=GetRecord&metadataPrefix=lom&identifier=oai:oer-repo.uibk.ac.at:e0d6bbfa-3945-437d-ba16-3c6fab848f37
  and a second Example
  https://repository.tugraz.at/oai2d?verb=GetRecord&metadataPrefix=lom&identifier=oai:repository.tugraz.at:vqyg5-xb977.

As mentioned above, some implementaion are returning content-type as text/xml like invenio, unfortunately others like edu-sharing returning application/xml. So the client shall be able to handle both!

oerhub.at harvests the data with a perl-based daemon. The implementation is based on OAI-Harvester 1.20. The Perl modul expects text/xml and supports the standard DC. Our module accepts in addition the application/xml and has the specific LOM-handler implemented. The tests are rewritten against maintend repos.

Required Elements (oerhub 1.2)

• Title - lom.general.title
• Author - lom.lifecycle.contribute.role.value (=Author) and the Name in lom.lifecycle.contribute.centity.vcard or lom.lifecycle.contribue.entity.langstring
• Mediatyp - lom.technical.format (mime/types)
• License - lom.rights.description (not only CC-BY, new: spdx.org/licenses)
• Classification - lom.classification.taxonpath (Öfos)
• Educational - lom.educational.learningresourcetype
• last changed Date/Upload - lom.lifecycle.version.datetime (custom element)

Required Elements (oerhub 1.3 and above)

• Learning Resource Type - lom.educational.learningresourcetype
• Language - lom.general.language

Preferred optional Elements

• Descripton - lom.general.description

Optional Elements

• Thumbnail - lom.technical.thumbnail

Custom LOM Elements

centity

centity is a customized element, which is introduced by edu-sharing for vcard support (used by UIBK). entity is the default one (used by TUGraz).

<lom:centity>
  <lom:vcard>
    BEGIN:VCARD VERSION:3.0 N:Mustermann;Max;;; FN:Max Mustermann TITLE:Ao. Univ. Prof. Dr. END:VCARD
  </lom:vcard>
</lom:centity>

FN is the common used one in oerhub. It is recommended to use the optional FN in vCard version 2.1 to show similar output for all connected repositories

Special Attribues

xml:lang

For the element langstring the attribute xml:lang is used.

<lom:title>
  <lom:langstring xml:lang="de">Wirtschaft integrativ verstehen</lom:langstring>
</lom:title>
<lom:description>
  <lom:langstring xml:lang="de">Einführungsvortrag zum Masterstudiengang Accounting, Auditing and Taxation</lom:langstring>
</lom:description>

Hint: The repository has to ensure that the language code corresponds to the text of the element to pass the accessibility check!

x-none

"x-none" is used for strings without language identification (controlled vocabular).

<lom:value>
  <lom:langstring xml:lang="x-none">Author</lom:langstring>
</lom:value>

FQDN

The Fully Qualified Domain Name FQDN is used as identifier for the catalog

identifier in header-Element

<header>
  <identifier>oai:$FQDN:$ObjID</identifier>
  <datestamp>2023-02-10T13:34:53Z</datestamp>
</header>

Example:

<header>
  <identifier>oai:gecko.aau.at:452</identifier>
  <datestamp>2023-02-10T13:34:53Z</datestamp>
</header>

catalog

<lom:general>
  <lom:identifier>
    <lom:catalog>$FQDN</lom:catalog>
    <lom:entry>
      <lom:langstring xml:lang="x-none">$ObjID</lom:langstring>
    </lom:entry>
  </lom:identifier>
  ...
</lom:general>

Example:

<lom:general>
  <lom:identifier>
    <lom:catalog>gecko.aau.at</lom:catalog>
    <lom:entry>
      <lom:langstring xml:lang="x-none">452</lom:langstring>
    </lom:entry>
  </lom:identifier>
  ...
</lom:general>

Vocabs

Creativ Commons

<lom:description>
  <lom:langstring xml:lang="x-t-cc-url">https://creativecommons.org/licenses/by-sa/4.0</lom:langstring>
</lom:description>

This uri is expected https://creativecommons.org/licenses/by-sa/4.0 and following the link shows the details of the license.

The ingester expects https://creativecommons.org/licenses/ as an example for the RegExp

$linkCC =~ /^https\:\/\/creativecommons.org\/licenses\/(.*)/ )

There is no short CC in the link. It is added by the ingester.

ÖFOS

The expected part of the source uri ends with /vocabs/oefos2012

if ( $taxonPath->{source} =~ /(.*)\/vocabs\/oefos2012$/ ) {

To get the Oefos ID the uri has /vocabs/oefos2012 and the id at the end

if ( ($prefixurl, $number) = $id =~ /(.*)\/vocabs\/oefos2012\/(.*)/ ) {

Media Typ

The mapping used:

Changes in oerhub 1.3:

• no Media Type mapping, use of mime/type as is
• open for spdx.org/license (except commercial one)
• All Vocabs are archived in the index (spdx, oefos2012, iso639, kim/hcrt)

spdx (Licenses)

oerhub 1.3 and above we introduce Software Package Data Exchange (spdx).

<lom:description>
  <lom:langstring xml:lang="x-t-cc-url">https://spdx.org/licenses/Apache-2.0</lom:langstring>
</lom:description>

expected URI: https://spdx.org/licenses/<Identifier>. <Identifier> is the Short Identifier. The link shows the remarks of the license.

ISO Language codes and translation (Languages)

The data for the language codes and translation is based on https://www.loc.gov/standards/iso639-2/php/code_list.php.

kim/hcrt (Learning Resource Type)

Our controlled vocabs are based from https://skohub.io/dini-ag-kim/hcrt/heads/master/w3id.org/kim/hcrt/scheme.en.html to define the Learning Resource Type.

<lom:educational>
  <lom:learningresourcetype>
    <lom:source>
      <lom:langstring xml:lang="x-none">https://w3id.org/kim/hcrt/scheme</lom:langstring>
    </lom:source>
    <lom:id>https://w3id.org/kim/hcrt/video</lom:id>
    <lom:entry>...
    </lom:entry>
  </lom:learningresourcetype>
</lom:educational>

expected URI: https://w3id.org/kim/hcrt/<Identifier>. <Identifier> is the identifier like video in the Example https://w3id.org/kim/hcrt/video

Links

• https://www.openarchives.org/
• https://metacpan.org/pod/Net::OAI::Harvester
• https://validator.oaipmh.com/
• https://en.wikipedia.org/wiki/Dublin_Core
• https://en.wikipedia.org/wiki/Learning_object_metadata
• https://standards.ieee.org/standard/1484_12_3-2020.html
• https://oer-repo.uibk.ac.at/lom/latest/
• https://www.data.gv.at/katalog/dataset/stat_ofos-2012
• https://www.doi.org/
• https://creativecommons.org/
• https://spdx.org/licenses/
• https://www.loc.gov/standards/iso639-2/php/code_list.php

Repos with OAI-PMH/LOM

• Invenio
  • https://repository.tugraz.at/
• edu-sharing
  • https://oer-repo.uibk.ac.at/
  • https://oer-portal.uni-graz.at/
  • https://oer.fh-salzburg.ac.at/
• Phaidra
  • https://phaidra.univie.ac.at/
  • https://door.donau-uni.ac.at/
  • https://phaidra.fh-kaernten.at/
• Other
  • https://gecko.aau.at/

Project Homepage

• https://www.openeducation.at/
• https://oerhub.at/