1. DSpace Users Group - Jan. 2007 DSpace As A Platform Creating Custom Interfaces With Content Packaging Plugins Don Gourley Washington Research Library Consortium DSpace User Group, Open Repositories 2007 Session 5

2. DSpace Users Group - Jan. 2007 DSpace As A Platform Agenda –DSpace Plugin Mechanism Introduced in version 1.4 –Example Application: Custom HTTP interface for the WRLC Digital Object Catalog

3. DSpace Users Group - Jan. 2007 Plugin Manager Plugin: Independently “pluggable” software component PluginManager: Java class that organizes/selects/creates plugins Plugin Interface: Defines a class of service Plugin Implementation: Service provider

4. DSpace Users Group - Jan. 2007 Types Of Plugins Singleton Plugin: One implementation of the class Sequence Plugins: Ordered set of implementations Named Plugin: Multiple available implementations –Names bound to implementation in config –Self-named

5. DSpace Users Group - Jan. 2007 Plugins in DSpace 1.4 AuthenticationMethod –Sequence plugins (implement a “stack”) –E.g. Password, LDAP MediaFilter –E.g. HTML, Word, PDF, JPEG BitstreamDispatcher –E.g. by Item or least-recently checked

6. DSpace Users Group - Jan. 2007 Metadata & Content Plugins DisseminationCrosswalk and IngestionCrosswalk –E.g. DC, QDC, MODS, METS, PREMIS –XSLT: define crosswalk with stylesheet PackageDisseminator and PackageIngester –E.g. METS, PDF

7. DSpace Users Group - Jan. 2007 Invoking Plugins Plugin Consumer: Java class that uses PluginManager –Configure plugin classes, names, options in dspace.cfg –Reload Web app for online consumers E.g. AuthenticationManager –Run command-line program E.g. Packager, MediaFilterManager, ChecksumChecker –Invoke via OAI-PMH: PluginCrosswalk

8. DSpace Users Group - Jan. 2007 Invoking Plugins Need a mechanism for invoking content packaging plugins with HTTP GET and POST requests (REST-style Web services) DisseminatePackageServlet –Invokes a named PackageDisseminator –Patch # 1442299 IngestPackageServlet –Invokes a named PackageIngester –Patch to be submitted soon

9. DSpace Users Group - Jan. 2007 Digital Object Catalog DSpace IngestPackageServlet DisseminatePackageServlet DIDL Ingester PluginURL Ingester PluginEAD Ingester Plugin DIDL Disseminator Plugin HTML Disseminator Plugin Bitstream Disseminator Plugin DCEditorDCMS Web siteEAD XForms DCEditorImgViewerXMLViewer HTTP POST HTTP GET or POST DOC Web site webui

10. DSpace Users Group - Jan. 2007 Dissemination Interface

11. DSpace Users Group - Jan. 2007 Submitting Ingestion Content IngestPackageServlet requires an HTTP POST request –DOC plugins generally expect XML –Must be done by browser if you want the DSpace session cookie for login context –Can’t post XML content with plain HTML Alternatives include: JavaScript (e.g. the XMLHttpRequest class) Browser plugin (e.g. XForms viewer)

12. DSpace Users Group - Jan. 2007 Submission Response What is the proper response to an ingestion request? –Successful => submission receipt If ingestion plugin also implements the DisseminationPackage interface, IngestPackageServlet will use it for response –Unsuccessful => detailed error message PluginException thrown to servlet

13. DSpace Users Group - Jan. 2007 Ingestion Interface

14. DSpace Users Group - Jan. 2007 Ingestion Interface

15. DSpace Users Group - Jan. 2007 Issues With HTTP Interfaces Security –DOC plugins use DSpace public API Access controlled by authorization system Sometimes need to override (e.g. recreating structural metadata bitstream) Performance –Comparable to native interfaces Functionality –Limited to content packaging plugins

16. DSpace Users Group - Jan. 2007 Web Services Applications Integration with content-specific workflow applications –E.g. ETD-db DLF-Aquifer “asset actions” Pathways “interoperability fabric” obtain, harvest & put services

17. DSpace Users Group - Jan. 2007 For More Information... Presentation write-up: http://dspace.wrlc.org/doc/wrlc/DSpaceAsAPlatform.pdf Wiki pages: http://wiki.dspace.org/index.php/PluginManager /CrosswalkPlugins /PackagerPlugins Me: gourley@wrlc.org