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OntologyReasoner

What it is​

  • A small utility for deduplicating RDF resources in a Turtle (TTL) ontology graph using rdflib.
  • Deduplication is based on having the same rdf:type and rdfs:label, merging triples into a single “main” subject.

Public API​

Class: OntologyReasoner​

is_iri_uuid(iri: URIRef) -> bool​

  • Checks whether the last path/fragment segment of an IRI matches a UUID pattern (8-4-4-4-12 lowercase hex).

dedup_subject(class_label: tuple, graph: Graph) -> Graph​

  • Deduplicates subjects in graph for a given (class_iri, label) pair.
  • Behavior:
    • Finds subjects ?s such that:
      • ?s a <class_iri>
      • ?s rdfs:label "label"
      • and excludes subjects that:
        • are a superclass of another resource (FILTER NOT EXISTS { ?other rdfs:subClassOf ?s })
        • are explicitly typed as owl:Class or rdfs:Class
    • Picks the first matching subject whose IRI ends with a UUID as the main node; otherwise creates a new node:
      • http://ontology.naas.ai/abi/<uuid4>
    • Merges data:
      • Copies non-rdf:type triples from duplicate subjects onto the main node
      • Rewrites object references pointing to duplicate subjects to point to the main node
      • Removes excluded duplicate subjects from the output graph

dedup_ttl(ttl: str) -> Tuple[str, Graph]​

  • Parses a Turtle string into a graph, finds duplicate subjects with the same (rdf:type, rdfs:label), and deduplicates them.
  • Returns:
    • A serialized Turtle string of the deduplicated graph
    • The deduplicated rdflib.Graph object
  • Preserves existing namespace bindings from the parsed graph.

Configuration/Dependencies​

  • Python dependencies:
    • rdflib
  • Standard library:
    • re, uuid, typing
  • Input format:
    • dedup_ttl expects Turtle (format="turtle").

Usage​

from naas_abi_core.utils.OntologyReasoner import OntologyReasoner

ttl = """
@prefix ex: <http://example.org/> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .

ex:a a ex:Thing ; rdfs:label "X" ; ex:p "v1" .
ex:b a ex:Thing ; rdfs:label "X" ; ex:p "v2" .
"""

reasoner = OntologyReasoner()
deduped_ttl, deduped_graph = reasoner.dedup_ttl(ttl)

print(deduped_ttl)

Caveats​

  • dedup_ttl asserts that all triple components are URIRef; graphs containing literals (including rdfs:label values) may trigger an AssertionError during iteration.
  • SPARQL in dedup_subject references owl:Class but does not declare the owl: prefix in the query; whether this works depends on the graph/query namespace handling in rdflib.
  • UUID detection in is_iri_uuid matches lowercase hex only.