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OntologyReasoner

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OntologyReasoner

What it is

  • Utility class for de-duplicating RDF resources in a Turtle (ttl) string.
  • Merges subjects that share the same rdf:type and rdfs:label, preferring a UUID-based IRI as the canonical subject.

Public API

Class: OntologyReasoner

is_iri_uuid(iri: rdflib.term.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: rdflib.Graph) -> rdflib.Graph

  • De-duplicates subjects in graph for a given (class_iri, label) pair.
  • Behavior:
    • Runs a SPARQL query to find subjects ?s with:
      • ?s a <class_iri>
      • ?s rdfs:label "label"
      • Excludes nodes that are superclasses of something (FILTER NOT EXISTS { ?other rdfs:subClassOf ?s })
      • Excludes nodes typed as owl:Class or rdfs:Class
    • Picks the first matching subject whose IRI ends with a UUID; otherwise creates a new subject IRI:
      http://ontology.naas.ai/abi/{uuid4}
    • For each non-canonical duplicate subject found:
      • Copies its non-rdf:type outgoing triples to the canonical subject.
      • Rewrites triples that reference the duplicate as an object to instead reference the canonical subject.
    • Rebuilds and returns a new graph excluding triples that mention removed duplicate IRIs.

dedup_ttl(ttl: str) -> tuple[str, rdflib.Graph]

  • Parses a Turtle string into an rdflib.Graph, identifies duplicates by (rdf:type, rdfs:label), and applies dedup_subject when multiple subjects share the same pair.
  • Returns:
    • Serialized Turtle string (with original namespace bindings re-bound)
    • The resulting rdflib.Graph

Configuration/Dependencies

  • Python dependencies:
    • rdflib
  • Standard library:
    • re, uuid, typing

Usage

from naas_abi_core.utils.OntologyReasoner import OntologyReasoner
 
ttl = """
@prefix ex: <http://example.com/> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
 
ex:a a ex:Person ; rdfs:label "Alice" ; ex:age 30 .
ex:b a ex:Person ; rdfs:label "Alice" ; ex:age 31 .
"""
 
reasoner = OntologyReasoner()
deduped_ttl, deduped_graph = reasoner.dedup_ttl(ttl)
 
print(deduped_ttl)

Caveats

  • dedup_ttl asserts that all triple components (s, p, o) are URIRef; Turtle containing literals (e.g., rdfs:label "Alice") will violate this assertion for the literal object and raise AssertionError.
  • The SPARQL query in dedup_subject references owl:Class but does not declare the owl: prefix in the query text; this may fail depending on the graph/query environment.
  • UUID detection only matches lowercase hex UUIDs (uppercase UUID IRIs will not be treated as UUID-based).

Graph View