RDFLib Ontology LSP

rdflib-ontology-lsp is a Python language server that adds autocomplete for rdflib.Namespace terms in Python files.

If your workspace contains:

from rdflib import Namespace

SKG = Namespace("https://sakuna.ph/")

and an ontology file contains:

@prefix skg: <https://sakuna.ph/> .
@prefix owl: <http://www.w3.org/2002/07/owl#> .

skg:Person a owl:Class .
skg:hasName a owl:DatatypeProperty .
skg:worksFor a owl:ObjectProperty .

then typing SKG. in a Python file can suggest Person, hasName, and worksFor.

Features

• Scans Python files for Namespace(...), rdflib.Namespace(...), aliased imports such as from rdflib import Namespace as NS, and simple string constants passed to Namespace(BASE_IRI).
• Scans ontology files matching **/*.ttl, **/*.owl, **/*.rdf, **/*.nt, and **/*.jsonld.
• Suggests only ontology local names that are valid Python dot-access identifiers.
• Includes the ontology type, full IRI, and source file in completion metadata.
• Shows rdfs:comment or skos:definition text in completion documentation when present.
• Refreshes the in-memory index when Python or ontology files change.
• Includes built-in suggestions for RDF, RDFS, SKOS, OWL, PROV-O, and GeoSPARQL namespace imports from RDFLib.

Install

From this repository:

python -m pip install -e ".[dev]"

This installs the server and development test dependency. Runtime dependencies are pygls and rdflib.

Run the Language Server

python -m rdflib_ontology_lsp.server

The server communicates over stdio, which is what the VS Code client uses.

Run Tests

python -m pytest

Example Files

The examples/ directory contains:

• examples/ontology.ttl
• examples/example.py

They demonstrate the https://sakuna.ph/ namespace and ontology terms.

VS Code Extension Development

1. Install the Python server from the repository root:

   python -m pip install -e ".[dev]"
   

2. Install and build the VS Code client:

   cd vscode-client
   npm install
   npm run compile
   

3. Open this repository, or vscode-client, in VS Code.

4. Press F5 to launch an Extension Development Host. The launch config opens this repository in the development host.

5. Type SKG. in examples/example.py after the detected Namespace("https://sakuna.ph/") assignment.

The client also adds the parent repository src directory to PYTHONPATH for local development, so it can run the server from source.

If suggestions do not appear automatically, run Trigger Suggest in VS Code or press Ctrl+Space after SKG.. Check Output: RDFLib Ontology Autocomplete for the Python executable, server cwd, and workspace scan messages.

Configuration

Default settings:

{
  "rdflibOntologyAutocomplete.ontologyFiles": [
    "**/*.ttl",
    "**/*.owl",
    "**/*.rdf",
    "**/*.nt",
    "**/*.jsonld"
  ],
  "rdflibOntologyAutocomplete.exclude": [
    "**/.venv/**",
    "**/venv/**",
    "**/node_modules/**",
    "**/.git/**"
  ],
  "rdflibOntologyAutocomplete.enableDiagnostics": false,
  "rdflibOntologyAutocomplete.enableStandardVocabularies": true,
  "rdflibOntologyAutocomplete.pythonPath": "",
  "rdflibOntologyAutocomplete.logLevel": "info"
}

Set rdflibOntologyAutocomplete.pythonPath to a Python executable or virtual environment directory if you want the extension to use a specific interpreter. The setting supports ${workspaceFolder}.

Set rdflibOntologyAutocomplete.enableStandardVocabularies to false if you only want suggestions from ontology files in the workspace.

Supported Ontology Types

The scanner indexes subjects with these RDF types:

• owl:Class
• rdfs:Class
• rdf:Property
• owl:ObjectProperty
• owl:DatatypeProperty
• owl:AnnotationProperty