DSpace DIDL Plug-In
Introduction | Disclaimer | Version
History | Latest
Release | Installation Instructions
This plug-in empowers a DSpace
repository to make its contained Items harvestable through
the OAI-PMH protocol.
Via the plug-in, DSpace Items are represented as MPEG-21 DIDL
objects. These DIDL objects are XML documents that wrap both the
Dublin Core metadata that describes the DSpace Item and its actual
bit streams. A bit streams is provided inline in the DIDL object
in a base64 encoded manner, and/or by means of a pointer to the
bit stream. The DSpace DIDL plug-in exposes DIDL objects via the
The module does not deal with special characters and purposely
skips dissemination of the license.txt file awaiting a better understanidng
on how to map DSpace rights information to MPEG21-DIDL.
This software is considered experimental. It was
produced by the Digital Library Research & Prototyping Team
of the Research Library of the Los Alamos National Laboratory. It
is, however, not officially endorsed neither by the Los Alamos National
Laboratory or by the DSpace community. No guarantees implicit or
explicit nor any form support are guaranteed. Feedback should be
provided via the SourceForge Forums.
- Version alpha 1 released 03-02-2004
- Initial Version that allowed DSpace 1, 1.1 system to
stream DIDL objects as responses to OAI-PMH requests
- This version implement a version of DIDL objects that
is no longer supported
- This version should not continue to be used, please upgrade
to the latest release
- You may still download the source code to proceed with
the installation of the plug-in here
- Version alpha 2 released 09-21-2004
- Version compatible with DSpace
v. 1.2 and above only
- Version supports revised version of the DIDL format for
representing complex objects.
- Version allows for the inclusion of didlmaxresponse parameter
to determine the maximum size of the bit streams to be provided
in a base64 encoded manner. Files bigger than the specified
value are passed by reference to reduce bandwidth and resource
strain on the repository.
- Version allows the administrator to set didlmaxresponse
to 0 in order to always provide bit streams by reference.
procedure is as follows:
To install the plug-in you need the following steps ( prior knowledge
on the ant and ant update procedure may be obtained in the DSpace
installation documents available at http://www.dspace.org):
- copy our did directory to <dspace source>/src/org/dspace/app/oai
- copy the file DIDLCroswalk.java to <dspace source>/src/org/dspace/app/oai/
- modify your file <dspace directory>/config/dspace.cfg
- add the following lines:
- #Max response size for DIDL
- dspace.didlmaxresponse = 0
<this is the maximum size in bytes of the files you wish to
enclose Base64 encoded in your responses, remember that the
base64 encoding process uses a lot of memory we recommend
at most 200000 for answers of 30 records each on a 1 Gigabyte
machine. We are actively working with OAI-CAT and DSpace
to change to a streaming model and get rid of this restriction.
Also please remember to allocate plenty of memory, at least
512 MB to your tomcat>
- (optional) DSpace uses 100 records as the limit for
the oai responses you can alter this by changing the file: <dspace
source>/src/org/dspace/app/oai/DSpaceOAICatalog.java . And
modify the declaration: private final int MAX_RECORDS = 100
private final int MAX_RECORDS = 30.
- execute ant on <dspace source>
- execute ant -Dconfig=<dspace directory>/config/dspace.cfg update
- stop tomcat
- delete the dspace, dspace-oai, dspace.war, dspace-oai.war from
your <jakarta home>/webapps/ and copy dspace.war and dspace-oai.war
from <dspace source>/build/ to <jakarta home>/webapps/
- modify your oaicat.properties files in /dspace/config and add
a last line that says : Crosswalks.didl=org.dspace.app.oai.DIDLCrosswalk
(Dspace advices changing the <dspace source>/config/oaicat.properties
instead and then follow the install config files procedure .
way should work)
- RESTART TOMCAT
Contact: Henry Jerez
Los Alamos National Laboratory
Research Library - Digital Library Research & Prototyping Team
email@example.com . Please provide feedback via the SourceForge Forums.