In order to allow central aggregators harvesting the CDM Community Stores the OAI-PMH protocol with selective date based harvesting has been implemented in to the CDM Community Stores. BHL, GBIF, EOL or any other data aggregator therefore are able to easily pool CDM data selectively and keep their copy up to date by accessing incremental changes only.
The CDM Community Store an an OAI-PMH disseminates different types items like taxa, references, and so on. Therefore the CDM OAI-PMH interface is split in to sub repositories which exist at different base URL. For each type another URL. The implementation of the OAI-PMH is equipped with a XSLT which renders a humane user interface when accessed with a browser.
Currently the following sub repositories exist (All URL are relative to the specific root of the CDM Community Server):
base URL: reference/oai
- oai_dc = http://www.openarchives.org/OAI/2.0/oai_dc.xsd
- dwc = http://rs.tdwg.org/dwc/xsd/simpledarwincore/ Requesting for an item in the '''dwc (Simple Darwin Core)''' metadata format will not return metadata on the reference item itself, but on all taxa (acceptend taxa and synonyms) covered by the specific reference and by all subordinary references.
Sets: * Any kind of reference
Those CDM DataStores willing to expose their data via the OAI-PMH interface can register at an OAI-PMH provider registry. The registry process can be triggered from the administrative overview page of the CDM Servers, which is usually available at http://my.server.name:8080/ .
This overview page shows a table listing all CDM Community Stores which are exposed by this specific CDM Community Server. CDM Community Stores which are not yet registered offer a Request for registration link. Clicking this link allows sending an email to the EDIT OAI-PMH provider registration service. Once a server has been registered this link is being replaced by a text indicating the registration state and the CDM Community Store is listed by the provider registry with according metadata. This list is returned in XML if not specified differently, whereas the data structure is defined by the XML schema. The OAI-PMH provider registry is a simple RESTful web service, all parameters are provided as URL parameters added to the base URL:
- find=<baseURL> : Search for an entry in the list of providers which matches the specified baseURL. Example: http://wp5.e-taxonomy.eu/registry/oai/providers.php?find=http%3a%2f%2fsome.cdmserver.com%3a8080%2fcdmStoreName providers.php?find=http://some.cdmserver.com:8080/cdmStoreName
- format=<fomat name> : Send the response data in a specific format. Valid format names are: json (application/json), xml (application/xml). Xml is being used as default format. Example: http://wp5.e-taxonomy.eu/registry/oai/providers.php?format=json providers.php?format=json
- callback=<jsonp callback> : This parameter allows specifying a JSONP callback, for an explanation of this feature please refer to http://www.ibm.com/developerworks/library/wa-aj-jsonp1/