Show the statements made by some RDF

show-statements.py

# encoding: utf-8
#
# show-statements.py — print some RDF
#
# To use this:
#
# python3 -m venv venv
# venv/bin/pip install --quiet --upgrade pip setuptools rdflib
# venv/bin/python show-statements.py URL


import rdflib, argparse


def read_rdf(source: str) -> dict:
    '''Parse the RDF at the given ``source`` and return a dictionary of the statements made.

    The dictionary is of the form ``{s: {p: [o]}}`` where ``s`` is a subject URI which maps to
    dictionaries whose keys are ``p`` predicate URIs who map to sequences of ``o`` objects.
    '''
    graph = rdflib.Graph()
    statements = {}
    graph.parse(source)
    for subject, predicate, obj in graph:
        predicates = statements.get(subject, {})
        objs = predicates.get(predicate, [])
        objs.append(obj)
        predicates[predicate] = objs
        statements[subject] = predicates
    return statements


def print_statements(statements: dict):
    '''Print the ``statements`` nicely.'''
    for subject, predicates in statements.items():
        print(f'🆔  SUBJECT f{subject} ' + '⎯' * 20)
        for predicate, objs in predicates.items():
            print(f'\t🏷  Predicate {predicate}')
            for obj in objs:
                print(f'\t\t {obj}')
        print()


def main():
    '''Parse the RDF on the command line and print it nicely.'''
    parser = argparse.ArgumentParser(description='Show statements made in an RDF source')
    parser.add_argument('source', help='URL to an RDF source')
    args = parser.parse_args()
    statements = read_rdf(args.source)
    print_statements(statements)


if __name__ == '__main__':
    main()