documents: export records in Dublic Core format

[sebdeleze]

This PR configures OAI server to export documents records in Dublin Core formats.

• Installs dcxml library to generate the output in Dublic CORE XML.
• Creates and configures the serializer for oai_dc format.
• Dumps mimetype from file object to record's file metadata.
• Adds a serializer schema for Dublic Core.
• Adds mimetype property to all resources that use files.
• Avoids to display issue and pages if volume is not defined in partOf property.
• Closes OAI-PMH Export format in Dublin Core (DC) #325.

Co-Authored-by: Sébastien Délèze sebastien.deleze@rero.ch

[pronguen]

Thank you, this is a big step forwards!

In this state, the data is already completely usable! Here what can still be improved:

• in dc:source, the data from [partOf.document.numberingPages] is missing (and maybe also number, volume...)
  • apparently, it is missing when I remove the volume. I think this comes from the spec that are not clear (If possible display "vol.", "nr." etc. only if a volume exists.). We should display the prefix "vol." only if this field exist, the prefix "nr." only if this field exist, the prefix "p." only if this field exist. Sorry!
  • This correction can be done later in an issue (just tell me to open the issue)

• in dc:rights, the value does not change if the file is embargoed, restricted or not. It should change.
  • works fine now 👌
• in dc:subject the classification is missing
  • works fine now 👌

[sebdeleze]

Thank you, this is a big step forwards!

In this state, the data is already completely usable! Here what can still be improved:

• in dc:source, the data from [partOf.document.numberingPages] is missing (and maybe also number, volume...)

  • apparently, it is missing when I remove the volume. I think this comes from the spec that are not clear (If possible display "vol.", "nr." etc. only if a volume exists.). We should display the prefix "vol." only if this field exist, the prefix "nr." only if this field exist, the prefix "p." only if this field exist. Sorry!
  • This correction can be done later in an issue (just tell me to open the issue)

Yes, you can create an issue as it's not fully related to this PR.