Hi Ben, When harvesting items via OAI-PMH with "oai_dc", DSpace harvests all external identifiers as "dc.identifier".
However, just before it saves the item, it will *search* through all 'dc.identifier' fields to attempt to find anything that looks to be a Handle (it uses the 'harvester.acceptedHandleServer' config in oai.cfg file). If it finds something that looks like a Handle, then it assigns that handle to the harvested item. This logic occurs in the OAIHarvester class. https://github.com/DSpace/DSpace/blob/master/dspace-api/src/main/java/org/dspace/harvest/OAIHarvester.java#L528 That area of the code usess the "extractHandle()" method which is what searches all 'dc.identifier' fields for a string that looks like the Handle: https://github.com/DSpace/DSpace/blob/master/dspace-api/src/main/java/org/dspace/harvest/OAIHarvester.java#L605 Hopefully that better explains what is going on in the OAI Harvester. - Tim On 6/23/2012 4:34 AM, Benjamin Ryan wrote: > Tim, > Thanks for the info. > This has me a little confused as I was sure I picked up this fix from a > reply in the mailing list. I am right in thinking that DSpace needs the > dc.identifier.uri field so it can display a link to the resource that has > been harvested instead of minting a new uri which will be a link to the > external handle system and then be resolved back to the DSpace resource by > the handle server. > If it the case that harvesting just oai_dc cannot support the display > of the link back to the harvested resource has is this normally achieved? > > Regards, > Ben > > ------------------------------------------------------------------ > Dr Ben Ryan > Jorum Technical Coordinator (Services) > > 5.12 Roscoe Building > The University of Manchester > Oxford Road > Manchester > M13 9PL > Tel: 0160 275 6039 > E-mail: [email protected] > ------------------------------------------------------------------ > > -----Original Message----- > From: Tim Donohue [mailto:[email protected]] > Sent: 22 June 2012 16:19 > To: Ben Ryan > Cc: [email protected] > Subject: Re: [Dspace-tech] OAI harvest not processing dc.identifier.uri > correctly > > Hi Ben, > > It sounds like you are trying to run an OAI-PMH Harvest of another site (in > this case it looks like an EPrints site) from the XMLUI interface. > > It looks like the main issue here is that the external site is giving you > *invalid* "oai_dc" metadata. As the OAI-PMH protocol states, "oai_dc" is > suppose to just be metadata of the format "dc.[element]": > http://www.openarchives.org/OAI/openarchivesprotocol.html > > However, in this sitution, there's a "dc.identifier.uri" field which is > Qualified Dublin Core (QDC) and not a valid oai_dc metadata field. > > This field is misunderstood by the DSpace OAI-PMH harvester, as the harvest > expects all fields to be valid oai_dc metadata. > > So, unfortunately, the main issue here is that the external site you are > harvesting is returning invalid metadata. > > The only way I can think of to "hack" a fix on the DSpace side of things > would be to modify the crosswalk that DSpace is using to transform the > "oai_dc" metadata into it's internal Qualified Dublin Core schema. The > crosswalk DSpace uses to perform this task is: > org.dspace.content.crosswalk.OAIDCIngestionCrosswalk > > It is configured by default in your dspace.cfg as the crosswalk to use > whenever DSpace encounters "dc:" namespaced fields (which are what you see in > your "oai_dc" metadata output below). That configuration is in this area of > your dspace.cfg: > https://github.com/DSpace/DSpace/blob/master/dspace/config/dspace.cfg#L484 > > Here's a few options I can think of: > > * You could create a *custom* crosswalk based on the > "OAIDCIngestionCrosswalk" that properly parse out this "dc.identifier.uri" > field and map it to the same field in DSpace. You'd want to configure this > modified crosswalk as being the one used for "dc" > metadata (see link above). > > * OR, it *might* be possible to just configure DSpace's QDCCrosswalk (which > can crosswalk Qualified Dublin Core) as the "dc:" metadata crosswalk. You'd > probably only want to do this temporarily & you'd want to test this on a > Test/Development Server (as I've *never* tried this and am not sure what > would happen, so it may error out). To do that, you'd change the "dc" > crosswalk config to point at the QDCCrosswalk class, e.g. > > plugin.named.org.dspace.content.crosswalk.IngestionCrosswalk = \ > ... > org.dspace.content.crosswalk.QDCCrosswalk = dc, \ > ... > > Good luck! > > - Tim > > > On 6/22/2012 12:47 AM, Ben Ryan wrote: >> Hi, >> I have attempted to harvest from an OAI feed and having some >> problems processing the dc.identifier.uri field. >> An example record from the feed is: >> <record> >> <header> >> <identifier>oai:generic.eprints.org:9</identifier> >> <identifier>http://humbox.ac.uk/9/</identifier> >> <datestamp>2012-06-11T18:48:56Z</datestamp> >> <setSpec>74797065733D7265736F75726365</setSpec></header> >> <metadata> >> <oai_dc:dc xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/"; >> xmlns:dc="http://purl.org/dc/elements/1.1/"; >> xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ >> http://www.openarchives.org/OAI/2.0/oai_dc.xsd"; >> xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance";> >> <dc:title>Using EEBO to compare the quarto and Folio editions of >> Shakespeare's Henry V</dc:title> >> <dc:identifier.uri>http://humbox.ac.uk/id/eprint/9</dc:identifier.uri> >> <dc:creator>University, Matthew Steggle, Sheffield Hallam</dc:creator> >> <dc:description>As EEBO has images of every book printed in England >> before 1700, it offers students studying Shakespeare the opportunity >> to look at both the quarto and Folio editions of his plays. By using >> EEBO to look at different editions of the same play we can start to >> think about the decisions made by editors when confronted with this >> dilemma of choice. Which version is best? We can also think about why >> these differences occur.</dc:description> >> <dc:date>2005</dc:date> >> <dc:type>Resource</dc:type> >> <dc:type>NonPeerReviewed</dc:type> >> <dc:format>application/msword</dc:format> >> >> <dc:identifier>http://humbox.ac.uk/9/2/EEBO_Quarto___Folio_of_Henry_V.doc</dc:identifier> >> <dc:identifier>Using EEBO to compare the quarto and Folio editions of >> Shakespeare's Henry V</dc:identifier> >> <dc:relation>http://humbox.ac.uk/9/</dc:relation> >> >> <dc:rights>Creative Commons Attribution Non-commercial Share Alike >> <http://creativecommons.org/licenses/by-nc-sa/2.5/></dc:rights>< >> /oai_dc:dc></metadata></record> The dc.identifier.uri field appears in >> the record. >> When I view the item in the full view it shows the field as >> dc.identifier.uri http://humbox.ac.uk/id/eprint/9 However when I view >> the METS metadat (using >> http://localhost:8080/xmlui/metadata/handle/123456789/4216/mets.xml) >> it shows the field as <dim:field element="identifier.uri" >> mdschema="dc"> >> http://humbox.ac.uk/id/eprint/233 >> </dim:field> >> In the database the metadat field is recorded in the metadatavalue >> table with a metadata_field_id of 72 and the entry in the >> metadatafieldregistry table shows the element name as identifier.uri >> as the field is unknown and I currently have harvester.unknownfield set to >> add. >> Can anybody point me to where I look to see why DSpace is not >> recognising the field (is it because of pattern matching for handles? >> Regards, >> Ben >> >> >> >> ---------------------------------------------------------------------- >> -------- >> Live Security Virtual Conference >> Exclusive live event will cover all the ways today's security and >> threat landscape has changed and how IT managers can respond. >> Discussions will include endpoint security, mobile security and the >> latest in malware threats. >> http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ >> >> >> >> _______________________________________________ >> DSpace-tech mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/dspace-tech >> > > > ------------------------------------------------------------------------------ > Live Security Virtual Conference > Exclusive live event will cover all the ways today's security and threat > landscape has changed and how IT managers can respond. Discussions will > include endpoint security, mobile security and the latest in malware threats. > http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ > _______________________________________________ > DSpace-tech mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/dspace-tech > ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ DSpace-tech mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/dspace-tech
