URI Dereferencer

Lightweight nginx Docker container for dereferencing Linked Data URIs via SPARQL DESCRIBE queries. Renders an interactive HTML view with property tables, WKT geometry on Leaflet maps, and content negotiation for RDF formats (Turtle, RDF/XML, JSON-LD). All JS libraries are bundled locally — no CDN tracking.

Quick Start

Pull the pre-built image from GitHub Container Registry:

docker pull ghcr.io/matdata-eu/uri-dereferencer:latest
docker run -p 8080:8080 \
  -e SPARQL_ENDPOINT=https://example.org/sparql \
  -e BASE_URI=https://example.org \
  ghcr.io/matdata-eu/uri-dereferencer:latest

Or build locally:

docker-compose up -d
# or
docker build -t uri-dereferencer .
docker run -p 8080:8080 -e SPARQL_ENDPOINT=https://jena.matdata.eu/rinf/sparql uri-dereferencer

Then open http://localhost:8080/{resource-uri}.

Configuration

Variable	Default	Description
SPARQL_ENDPOINT	https://jena.matdata.eu/rinf/sparql	SPARQL endpoint URL
BASE_URI	https://data.matdata.eu	Entity namespace for local vs external URI routing and nginx content negotiation

Usage

Production — the URL is the URI:

https://data.matdata.eu/_netPointReferences_swi366_on_ne_348

Local testing — pass the full URI in the path:

http://localhost:8080/http://example.org/resource/123

Content Negotiation

Click the format badges in the UI, or use Accept headers:

curl -H "Accept: text/turtle" http://localhost:8080/{uri}
curl -H "Accept: application/rdf+xml" http://localhost:8080/{uri}
curl -H "Accept: application/ld+json" http://localhost:8080/{uri}

Geospatial

WKT geometries linked via gsp:hasGeometry are automatically rendered on a Leaflet map. Supports standard WKT, EWKT with SRID, and OpenGIS CRS format. Built-in EPSG definitions for 4326, 3857, 31370, 4258, 3035, 25832, 25833; others fetched from epsg.io.

Architecture

nginx serves a client-side SPA. The browser extracts the URI from the URL path, runs DESCRIBE against the SPARQL endpoint, parses N-Triples with N3.js, and renders properties, geometry (betterknown + Leaflet + proj4), and related resources.

├── Dockerfile / docker-compose.yml / nginx.conf / entrypoint.sh
├── index.html
├── assets/
│   ├── js/          (config.js, dereferencer.js, map-viewer.js)
│   ├── css/         (dereferencer.css)
│   ├── data/        (prefixes.json)
│   └── vendor/      (bootstrap, bootstrap-icons)
└── vendor/          (n3, leaflet, proj4, betterknown)

Dependencies

All libraries bundled locally:

Library	Version	Purpose
N3.js	1.17.2	RDF parsing
Leaflet	1.9.4	Interactive maps
proj4	2.9.2	Coordinate transforms
betterknown	1.1.1	WKT → GeoJSON
Bootstrap	5.3.3	UI framework

Development

# Without Docker — any HTTP server works:
python -m http.server 8080
# Edit assets/js/config.js to set SPARQL_ENDPOINT, then open http://localhost:8080/{uri}

# Rebuild Docker:
docker-compose down && docker-compose build --no-cache && docker-compose up -d

License

Licensed under the Apache License 2.0. Part of the MatData semantic-tools collection.