Import DNB ids from MARC records

[hornc]

Enables internetarchive/openlibrary-bots#29

Adds the ability to import Deutsche Nationalbibliothek (DNB) identifiers into Open Library from library MARC records (such as those made available to the public directly by DNB themselves, under a CC0 license).

Technical

This takes the DNB identifier from MARC field 016$a (National Bibliographic Agency Control Number) if the 016$2 (source) is DE-101

• MARC21 016 field description: https://www.loc.gov/marc/bibliographic/bd016.html
• DNB = DE-101: https://sigel.staatsbibliothek-berlin.de/en/suche/?q=DE-101

Source data for importing / testing: https://archive.org/details/marc_dnb_202006

Testing

Tested locally using the /api/import/ia endpoint -- newly imported DNB MARC record has the identifier as shown in the screenshot below, importing from this record: https://openlibrary.org/show-records/marc_dnb_202006/dnb_all_dnbmarc_20200615-2.mrc:0:953

Screenshot:

Links to http://d-nb.info/810887746

Update to the history sources list to display the import source:

Stakeholders

@GLBW
@mekarpeles

[tfmorris]

The English name of the library is "German National Library" cf https://www.dnb.de/EN/Home/home_node.html