Get some usable JSON for a given LC name or subject authority string: e.g. `./lcauthority.py "Southampton (England)"`

lcauthority.py

#!/usr/bin/env python3

"""
A small command line tool to get the JSON-LD for a Library of Congress authority
record by first looking up the authority as a string using the label lookup
service and then getting the JSON-LD for the authority and writing it out using
a JSON-LD frame where the SKOS is the default vocabulary.
"""

import sys
import json
import requests

from pyld import jsonld


def get_authority(label):
    # lookup the id.loc.gov URI for the label (the RDF includes HTTP URIs)
    resp = requests.get(f'https://id.loc.gov/authorities/label/{label}', allow_redirects=False)
    if resp.status_code == 404:
        return None
    uri = resp.headers['Location'].replace('https://', 'http://')

    # fetch the JSON-LD    
    doc = requests.get(uri, headers={"Accept": "application/ld+json"}).json()

    # use this context to parse the JSONLD into something more usable
    context = {
        "mads": "http://www.loc.gov/mads/rdf/v1#",
        "@vocab": "http://www.w3.org/2004/02/skos/core#",
        "skosxl": "http://www.w3.org/2008/05/skos-xl#",
        "recordinfo": "http://id.loc.gov/ontologies/RecordInfo#",
        "identifiers": "http://id.loc.gov/vocabulary/identifiers/",
        "bflc": "http://id.loc.gov/ontologies/bflc/",
        "iso6392": "http://id.loc.gov/vocabulary/iso639-2/",
        "changeset": "http://purl.org/vocab/changeset/schema#"
    }

    # "frame" the JSON-LD
    return jsonld.frame(doc, {
        "@context": context,
        "@id": uri,
        # so we get linked SKOS Concepts in addition to linked MADS Authorities
        "@embed": "@always",
    })


if __name__ == "__main__":
    if len(sys.argv) != 2:
        sys.exit("Usage: lcauthority.py <authority string>")
    print(json.dumps(get_authority(sys.argv[1]), indent=2))

southampton.json

{
  "@context": {
    "mads": "http://www.loc.gov/mads/rdf/v1#",
    "@vocab": "http://www.w3.org/2004/02/skos/core#",
    "skosxl": "http://www.w3.org/2008/05/skos-xl#",
    "recordinfo": "http://id.loc.gov/ontologies/RecordInfo#",
    "identifiers": "http://id.loc.gov/vocabulary/identifiers/",
    "bflc": "http://id.loc.gov/ontologies/bflc/",
    "iso6392": "http://id.loc.gov/vocabulary/iso639-2/",
    "changeset": "http://purl.org/vocab/changeset/schema#"
  },
  "@id": "http://id.loc.gov/authorities/names/n79072768",
  "@type": [
    "mads:Geographic",
    "mads:Authority",
    "Concept"
  ],
  "bflc:marcKey": "151  $aSouthampton (England)",
  "identifiers:lccn": "n 79072768",
  "identifiers:local": "(OCoLC)oca00305516",
  "mads:adminMetadata": [
    {
      "@type": "recordinfo:RecordInfo",
      "recordinfo:languageOfCataloging": {
        "@id": "iso6392:eng"
      },
      "recordinfo:recordChangeDate": {
        "@type": "http://www.w3.org/2001/XMLSchema#dateTime",
        "@value": "1979-08-16T00:00:00"
      },
      "recordinfo:recordContentSource": {
        "@id": "http://id.loc.gov/vocabulary/organizations/dlc"
      },
      "recordinfo:recordStatus": {
        "@type": "http://www.w3.org/2001/XMLSchema#string",
        "@value": "new"
      }
    },
    {
      "@type": "recordinfo:RecordInfo",
      "recordinfo:languageOfCataloging": {
        "@id": "iso6392:eng"
      },
      "recordinfo:recordChangeDate": {
        "@type": "http://www.w3.org/2001/XMLSchema#dateTime",
        "@value": "2014-04-25T17:12:06"
      },
      "recordinfo:recordContentSource": {
        "@id": "http://id.loc.gov/vocabulary/organizations/dlc"
      },
      "recordinfo:recordStatus": {
        "@type": "http://www.w3.org/2001/XMLSchema#string",
        "@value": "revised"
      }
    }
  ],
  "mads:authoritativeLabel": "Southampton (England)",
  "mads:code": {
    "@type": "http://id.loc.gov/datatypes/codes/gac",
    "@value": "e-uk-en"
  },
  "mads:editorialNote": "[Old catalog heading: Southampton, Eng.]",
  "mads:elementList": {
    "@list": [
      {
        "@type": "mads:GeographicElement",
        "mads:elementValue": "Southampton (England)"
      }
    ]
  },
  "mads:hasCloseExternalAuthority": [
    {
      "@id": "https://id.worldcat.org/fast/1343677",
      "@type": [
        "mads:Authority",
        "Concept"
      ],
      "mads:authoritativeLabel": "England Southampton Region",
      "prefLabel": "England Southampton Region"
    },
    {
      "@id": "https://id.worldcat.org/fast/1205666",
      "@type": [
        "mads:Authority",
        "Concept"
      ],
      "mads:authoritativeLabel": "England Southampton",
      "prefLabel": "England Southampton"
    },
    {
      "@id": "http://data.bnf.fr/ark:/12148/cb11962315f",
      "@type": [
        "mads:Authority",
        "Concept"
      ],
      "mads:authoritativeLabel": {
        "@language": "fr",
        "@value": "Southampton (GB)"
      },
      "prefLabel": {
        "@language": "fr",
        "@value": "Southampton (GB)"
      }
    },
    {
      "@id": "http://www.wikidata.org/entity/Q79848",
      "@type": [
        "mads:Authority",
        "Concept"
      ],
      "mads:authoritativeLabel": "Southampton",
      "prefLabel": "Southampton"
    },
    {
      "@id": "https://id.worldcat.org/fast/1343676",
      "@type": [
        "mads:Authority",
        "Concept"
      ],
      "mads:authoritativeLabel": "England Southampton Metropolitan Area",
      "prefLabel": "England Southampton Metropolitan Area"
    }
  ],
  "mads:hasEarlierEstablishedForm": {
    "@type": [
      "mads:Geographic",
      "mads:Variant"
    ],
    "mads:elementList": {
      "@list": [
        {
          "@type": "mads:GeographicElement",
          "mads:elementValue": "Southampton (Hampshire)"
        }
      ]
    },
    "mads:variantLabel": "Southampton (Hampshire)"
  },
  "mads:hasExactExternalAuthority": {
    "@id": "http://viaf.org/viaf/sourceID/LC%7Cn++79072768#skos:Concept"
  },
  "mads:hasSource": [
    {
      "@type": "mads:Source",
      "mads:citationSource": "Adshead, S. D.  The replanning of Southampton, 1942.",
      "mads:citationStatus": "found"
    },
    {
      "@type": "mads:Source",
      "mads:citationNote": "(Southampton (England))",
      "mads:citationSource": "BL hdg.",
      "mads:citationStatus": "found"
    },
    {
      "@type": "mads:Source",
      "mads:citationNote": "t.p. (County Borough of Southampton)",
      "mads:citationSource": "Annual report on school medical work ... 1923:",
      "mads:citationStatus": "found"
    },
    {
      "@type": "mads:Source",
      "mads:citationNote": "(ppl; 50\u00b054\u02b900\u02baN 001\u00b024\u02b900\u02baW)",
      "mads:citationSource": "GeoNames, algorithmically matched, 2009",
      "mads:citationStatus": "found"
    }
  ],
  "mads:hasVariant": [
    {
      "@type": [
        "mads:Geographic",
        "mads:Variant"
      ],
      "mads:elementList": {
        "@list": [
          {
            "@type": "mads:GeographicElement",
            "mads:elementValue": "Southampton (Hampshire)"
          }
        ]
      },
      "mads:variantLabel": "Southampton (Hampshire)"
    },
    {
      "@type": [
        "mads:Geographic",
        "mads:Variant"
      ],
      "mads:elementList": {
        "@list": [
          {
            "@type": "mads:GeographicElement",
            "mads:elementValue": "County Borough of Southampton"
          }
        ]
      },
      "mads:variantLabel": "County Borough of Southampton"
    }
  ],
  "mads:identifiesRWO": {
    "@id": "http://id.loc.gov/rwo/agents/n79072768",
    "@type": [
      "mads:RWO",
      "http://www.loc.gov/standards/mads/rdf/v1#Geographic"
    ],
    "bflc:subjectOf": [
      {
        "@id": "http://id.loc.gov/resources/works/7394958",
        "@type": "http://id.loc.gov/ontologies/bibframe/Work",
        "bflc:aap": "Adshead, S. D. replanning of Southampton: report of S.D. Adshead ... and H. T. Cook ... the the Council of the county borough of Southampton. With a section on buildings and monuments of historical and architectural value, by O. G. S. Crawford, F.S.A. February 1942"
      },
      {
        "@id": "http://id.loc.gov/resources/works/9692091",
        "@type": "http://id.loc.gov/ontologies/bibframe/Work",
        "bflc:aap": "Southampton Civic Society. Civic Survey Committee. Southampton; a civic survey, being a report of the Civic Survey Committee of the Southampton Civic Society under the chairmanship of Brigadier E.M. Jack .."
      }
    ],
    "http://www.w3.org/2000/01/rdf-schema#label": "Southampton (England)"
  },
  "mads:isMemberOfMADSCollection": [
    {
      "@id": "http://id.loc.gov/authorities/names/collection_NamesAuthorizedHeadings"
    },
    {
      "@id": "http://id.loc.gov/authorities/names/collection_LCNAF"
    }
  ],
  "mads:isMemberOfMADSScheme": {
    "@id": "http://id.loc.gov/authorities/names"
  },
  "altLabel": [
    "Southampton (Hampshire)",
    "County Borough of Southampton"
  ],
  "changeNote": [
    {
      "@type": "changeset:ChangeSet",
      "changeset:changeReason": {
        "@type": "http://www.w3.org/2001/XMLSchema#string",
        "@value": "new"
      },
      "changeset:createdDate": {
        "@type": "http://www.w3.org/2001/XMLSchema#dateTime",
        "@value": "1979-08-16T00:00:00"
      },
      "changeset:creatorName": {
        "@id": "http://id.loc.gov/vocabulary/organizations/dlc"
      },
      "changeset:subjectOfChange": {
        "@id": "http://id.loc.gov/authorities/names/n79072768"
      }
    },
    {
      "@type": "changeset:ChangeSet",
      "changeset:changeReason": {
        "@type": "http://www.w3.org/2001/XMLSchema#string",
        "@value": "revised"
      },
      "changeset:createdDate": {
        "@type": "http://www.w3.org/2001/XMLSchema#dateTime",
        "@value": "2014-04-25T17:12:06"
      },
      "changeset:creatorName": {
        "@id": "http://id.loc.gov/vocabulary/organizations/dlc"
      },
      "changeset:subjectOfChange": {
        "@id": "http://id.loc.gov/authorities/names/n79072768"
      }
    }
  ],
  "closeMatch": [
    {
      "@id": "https://id.worldcat.org/fast/1343677",
      "@type": [
        "mads:Authority",
        "Concept"
      ],
      "mads:authoritativeLabel": "England Southampton Region",
      "prefLabel": "England Southampton Region"
    },
    {
      "@id": "https://id.worldcat.org/fast/1205666",
      "@type": [
        "mads:Authority",
        "Concept"
      ],
      "mads:authoritativeLabel": "England Southampton",
      "prefLabel": "England Southampton"
    },
    {
      "@id": "http://data.bnf.fr/ark:/12148/cb11962315f",
      "@type": [
        "mads:Authority",
        "Concept"
      ],
      "mads:authoritativeLabel": {
        "@language": "fr",
        "@value": "Southampton (GB)"
      },
      "prefLabel": {
        "@language": "fr",
        "@value": "Southampton (GB)"
      }
    },
    {
      "@id": "http://www.wikidata.org/entity/Q79848",
      "@type": [
        "mads:Authority",
        "Concept"
      ],
      "mads:authoritativeLabel": "Southampton",
      "prefLabel": "Southampton"
    },
    {
      "@id": "https://id.worldcat.org/fast/1343676",
      "@type": [
        "mads:Authority",
        "Concept"
      ],
      "mads:authoritativeLabel": "England Southampton Metropolitan Area",
      "prefLabel": "England Southampton Metropolitan Area"
    }
  ],
  "editorialNote": "[Old catalog heading: Southampton, Eng.]",
  "exactMatch": {
    "@id": "http://viaf.org/viaf/sourceID/LC%7Cn++79072768#skos:Concept"
  },
  "inScheme": {
    "@id": "http://id.loc.gov/authorities/names"
  },
  "notation": {
    "@type": "http://id.loc.gov/datatypes/codes/gac",
    "@value": "e-uk-en"
  },
  "prefLabel": "Southampton (England)",
  "skosxl:altLabel": [
    {
      "@type": "skosxl:Label",
      "skosxl:literalForm": "Southampton (Hampshire)"
    },
    {
      "@type": "skosxl:Label",
      "skosxl:literalForm": "County Borough of Southampton"
    }
  ]
}

I solved the same problem without JSON-LD compaction using the code below.

I agree that LC should define a useful context and compact their data so we all don't have to do #%^@(&#%^ like this!

    def reconstitute(self, js, nodes):
        # recursively build tree from @graph node list
        # only replace into tree once to ensure non-infinite-recursion
        # ignore number, string, etc values
        del nodes[js['@id']]
        for (k,v) in js.items():
            if type(v) == dict and '@id' in v and v['@id'] in nodes:
                js[k] = self.reconstitute(nodes[v['@id']], nodes)
            elif type(v) == list:
                new = []
                for vi in v:
                    if type(vi) == dict and '@id' in vi and vi['@id'] in nodes:
                        new.append(self.reconstitute(nodes[vi['@id']], nodes))
                    else:
                        new.append(vi)
                js[k] = new
        return js

  def process(self, rec):
        nodes = {}
        for n in rec['@graph']:
            try:
                nodes[n['@id']] = n
            except:
                pass
        if '@id' in rec and rec['@id'].startswith('/authorities/'):
            ident = rec['@id'].rsplit('/', 1)[1]
            topid = f"{namespace}{ident}"
        elif '@context' in rec and type(rec['@context']) == dict:
            topid = rec['@context']['about']
        else:
           # no way to know the top of the tree
           return None

        try:
            return self.reconstitute(nodes[topid], nodes)    
        except:
            return None
       

(some internal processing elided for ease)

Yeah, I noticed the compaction wasn't needed too. I updated the gist accordingly.

https://github.com/edsu/idloc/blob/main/idloc.py#L122-L130