OAI-PMH Repository is a plugin for Omeka that implements an Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH) repository for Omeka, allowing Omeka items, collections, and files to be harvested by OAI-PMH harvesters. The plugin implements version 2.0 of the protocol.
This readme is available in French.
Uncompress the zip inside the folder plugin and rename it OaiPmhRepository.
See general end user documentation for Installing a plugin.
The end point of the service.
Default: oai-pmh-repository/request
Name for this OAI-PMH repository. This value is sent as part of the response to an Identify request, and it is how the repository will be identified by well-behaved harvesters.
Default: The name of the Omeka installation.
The oai-identifier specification requires repositories to specify a namespace identifier. This will be used to form globally unique IDs for the exposed metadata items. This value is required to be a domain name you have registered. Using other values will generate invalid identifiers.
Default: If it can, the plugin will try to automatically detect the domain of
the server hosting the site, and use that as the default namespace identifier.
If a name can’t be detected (for example, if the site is accessed through the
localhost domain), the default will be default.must.change (as you might
think, this value is intended to be changed, not used as-is). The plugin will
function with this, or any other string, as the namespace identifier, but this
breaks the assumption that each identifier is globally unique. Best practice is
to set this value to the domain name the Omeka server is published at, possibly
with a prefix like "oai."
Sets allow to gather items together to simplify partial harvesting. Three types of sets can be use: collection, item type and Dublin Core : Type.
Default: Collections
Whether the repository should expose direct URLs to all the files associated with an item as part of its returned metadata. This gives harvesters the ability to directly access the media described by the metadata.
Default: true
Whether the plugin should expose empty collections. If enabled, only collections that actually contain at least one public item will be included in the ListSets output. If disabled, all public oai sets are included in ListSets output.
Default: true
Whether the plugin should expose the item type as Dublin Core Type.
Default: false
The thumbnail may be exposed as Dublin Core : Relation.
Default: false
The oai sets are identified with a unique identifier, that must be different between different types of sets. So, check if they are no duplicate between names. Furthermore, only some characters are allowed. Forbidden names will be skipped. Diacritics are removed in the names, but they can be used if they are managed automatically by the database and php.
When the format is hierarchic, all oai set identifiers are prefixed with the type (item set, item type or dctype). When the format is flat, all oai set identifiers are simply listed and mixed.
Default: hierarchic
The format can be itemset_id, or the first Dublic Core identifier or title. In
all cases, they are normalized (no spaces, etc.).
The format can be type_id, or the item type name.
Apply the custom oai_dc output. By default, it follows the recommandations of the Europeana digital library and the Bibliothèque nationale de France.
The files data/oaidc_custom_record.php and data/oaidc_custom_set.php may
be adapted to complete data, for example to add a new type of document. An
additional guide is available in the header of these files.
Note: Dublin Core types are not available for releases before Omeka 2.5: the
search is not possible in derived sets. To use it, you need to hack the file
application/models/Table/Item.php: replace the method Table_Item::_advancedSearch()
by the one of Omeka 2.5 or later.
This three letters language (ISO 639-2b) allows to define the default language of metadata in order to translate them. This option is used only to normalize the custom metadata.
The OAI-PMH pages can be displayed and browsed with a themable responsive human
interface based on Bootstrap. To theme it, create a directory oai-pmh-repository/xsl
in your theme and copy the file oai-pmh-repository.xsl inside it, then edit
it. The css file can be copied and updated as well.
The plugin also allows you to configure some more options about how the repository responds to harvesters. Since the default values are recommended for most users, these values must be edited by hand, in the config.ini file in the plugin's root directory.
Number of individual items that can be returned in a response at once. Larger values will increase memory usage but reduce the number of database queries and HTTP requests. Smaller values will reduce memory usage but increase the number of DB queries and requests.
Default: 50
Amount of time in minutes a resumptionToken is valid for. The specification suggests a number in the tens of minutes. This boils down to the length of time a harvester has to request the next part of an incomplete list request.
Default: 10 (minutes)
The plugin ships with several default formats. Other plugins can alter these or add their own.
Dublin Core (prefix oai_dc)
The Dublin Core is required by the OAI-PMH specification for all repositories. Omeka metadata fields are mapped one-to-one with fields for this output format.
The Qualified Dublin Core format supports the additional elements added by Dublin Core Extended. For installations that don't use "extended" elements, the metadata output will be the same as for oai_dc.
Added in version 2.2 (official)
CDWA Lite (prefix cdwalite)
The mapping between Omeka’s metadata and CDWA Lite metadata is more complicated, and certain fields may not be populated correctly. The chief advantage of using CDWA Lite output is that file URLs can be output in a controlled format, unlike Dublin Core. Harvesters may therefore be able to harvest or link to files in addition to metadata.
MODS (prefix mods)
This output crosswalks the Dublin Core metadata to MODS using the mapping recommended by the Library of Congress.
METS (prefix mets)
The Metadata Encoding and Transmission Standard format exposes files to harvesters alongside Dublin Core metadata.
RDF (prefix rdf)
This format exposes metadata as RDF/XML. Unlike many of the other formats, RDF allows the repository to expose metadata from different standards all in the same output. The main practical distinction from other formats currently is that the RDF output will automatically include "qualified" data from the Dublin Core Extended plugin, if it's present.
Omeka XML (prefix omeka-xml)
This output format uses an Omeka-specific XML output that includes all metadata elements without requiring crosswalking or subsetting, but is not well-supported by harvesters or other tools and because the RRCHNM itself removed the schema from the last site.
The plugin provides a filter that other plugins can use to add new metadata formats or replace the existing ones with new implementations. As of version 2.1, it's no longer necessary to add or change files within the plugin itself to change the available formats.
The filter passes no extra parameters. The value being filtered is an array of
arrays, where each inner array describes a single metadata format. The key in
the outer array is the metadata prefix for the format (i.e., oai_dc or rdf).
Each inner array has three mandatory keys:
classis the name of a class implementingOaiPmhRepository_Metadata_FormatInterface. This class holds the actual implementation of the format.namespaceis the XML namespace for the format.schemais the location of the XML schema for the format.
2.1.1
- Fixed a bug with XML special characters in Collection names
- New translations: Catalan, Czech, German, Mongolian, Polish, Portuguese (Brazil), Portuguese (Portugal), Serbian
2.1
- New RDF metadata format
- New
oai_pmh_repository_metadata_formatsfilter to allow other plugins to add and modify metadata formats - Localization support (contributed by jajm)
- New option to exclude empty collections from ListSets (contributed by Daniel-KM
- New option to expose item type as Dublin Core Type value (contributed by [Daniel-KM
- More accurate "earliest datestamp" calculation (contributed by Daniel-KM
- Fixed "expose files" flag check for METS and omeka-xml outputs (contributed by Daniel-KM
- Additional miscellaneous cleanup (significant portions contributed by Daniel-KM
2.0
- Initial support for Omeka 2.0 and up
- File exposure support for METS
Use it at your own risk.
It’s always recommended to backup your files and your databases and to check your archives regularly so you can roll back if needed.
See online issues on the plugin issues page on GitHub.
This plugin is published under GNU/GPL.
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
Human interface (xslt stylesheet)
The human interface is published under the CeCILL-B BSD-like licence. See its header for other licenses notes.
See commits for full list of contributors.
- Copyright Yu-Hsun Lin, 2009
- Copyright John Flatness, 2009-2016
- Copyright Julian Maurice for BibLibre, 2016-2017
- Copyright Daniel Berthereau, 2014-2019 (see Daniel-KM)
Improvements of 2019 were built for Bibliothèque interuniversitaire de la Sorbonne.