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DataCite wants to get metadata of the objects the DOIs addresses. The DataCite Schema (http://schema.datacite.org) defines an XML structure to describe the metadata of an object. We developed a DIM2DataCite crosswalk that takes the metadata of a DSpace Item and transforms it into a XML using DataCite Schema 2.2. As far as I know, EZID does not use this XML so another crosswalk is probably needed. It should be discussed (see below or in the JIRA ticket) how we want to deal with metadata updates, as the API for external identifiers does not define a mechanism to update metadata for an external identifier yet.

DOIOrganiser

While developping DOI support for DSpace we recognized that DSpace would become dependent on the registration agencies API. If the API is offline or malfunctioning for any reason DSpace wouldn't be able to receive new submissions. To resolve this dependency we introduced DOIOrganiser. Instead of reserving and registering DOIs at the moment DSpace asks to, we just write into the database that a DOI should be reserved or registered. A cronjob checks periodically if there are DOIs to reserve or register. If the registration agencies API is offline, DSpace can still get new submissions. In case of an error, the cronjob will retry to reserve or register a DOI when it runs the next time.

The downside of this design decision is that there's a delay in reservation and registration of DOIs. However the duration of the delay depends on how often you run the cronjob. The big advantage is that DSpace stays independent from the status of external services (in this case the registration agencies API). For further information how to use the DOIOrganiser see the online help ([dspace-install]/bin/dspace doi-organiser --help).

How to Test

To test our code, you will need a login to be able to use the DataCite Test API. The test system can be found here: https://test.datacite.org. This URL is currently used for the API in dspace/config/spring/api/identifier-service.xml. In this file you have to remove to comments around the bean for the DOIIdentifier and around the bean for the DataCiteConnector. In dspace.cfg you'll have to configure the properties identifier.doi.user, identifier.doi.password, identifier.doi.prefix and identifier.doi.namespaceseparator. You can use the "TIB.DSPACE" user, the "duraspace" password, the 10.0128 prefix and as namespace separator a string that you don't expect anyone else would be using. DOIs that gets registered with these settings will be deleted regularly. DOIs that get registered with these properties must address an item using example.org as domain (or any subdomain below it). So you have to configure dspace.url to include example.org as domain (sorry, that is a rule of our DOI registration agency)!

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