WebVOWL

Fork of WebVOWL, an OWL ontology visualizer, with a modernized stack and additional capabilities. This fork adds Canvas rendering, ABox visualization, multiple graph layouts, and optional SPARQL endpoint support. OWL2VOWL (the OWL→VOWL converter) ships as a bundled submodule — no separate install required. Runs fully locally or via Docker.

Quick Start

Path A — Docker (recommended)

Docker gives you the full stack (nginx + OWL2VOWL sidecar) with no local Java or Node required at runtime. Fuseki integration is optional — you can load ontologies from URLs or files without it.

1. Initialize the submodule:

   git submodule update --init
   

2. Copy the env file (edit only if you're using Fuseki):

   cp .env.example .env
   

3. Build and start:

   docker compose up --build -d
   

4. Open http://localhost:8080

Path B — Local development

For working on the code. Requires Node.js 18+.

1. Install dependencies:

   npm install
   

2. Start the dev server with hot reloading:

   npm run dev
   

   Open http://localhost:8080

Or build a static production bundle:

npm run release
serve deploy/

Loading Ontologies

OWL2VOWL converts OWL/RDF into the VOWL JSON format that WebVOWL renders. Three ways to load an ontology:

• By URL — paste any publicly accessible OWL/RDF URL into the ontology menu
• By file — use the file picker in the ontology menu to load a local file
• From Fuseki — see Fuseki Integration below

Fuseki Integration (Optional)

nginx sits in front of everything. When OWL2VOWL needs to fetch from Fuseki, it sends the request to http://server/fuseki/.... nginx intercepts that path, injects your Authorization header from .env, and forwards the request to Fuseki — so credentials never touch OWL2VOWL.

Prerequisites

• An external semantic-web Docker network shared with your Fuseki stack:

  docker network create --internal semantic-web
  

  The --internal flag blocks internet access — containers communicate only within the network. Ensure your Fuseki stack also joins this network.
• Set FUSEKI_AUTH_HEADER in .env:

  # Basic auth:
  FUSEKI_AUTH_HEADER=Basic $(echo -n "user:password" | base64)
  # Bearer token:
  FUSEKI_AUTH_HEADER=Bearer <token>
  

Loading from Fuseki

Enter this IRI pattern in the WebVOWL ontology menu:

http://server/fuseki/<dataset>/data?graph=<graph-uri>

For example, if Fuseki has a bfo dataset: http://server/fuseki/bfo/data

The /fuseki/ prefix routes through nginx, which strips it and forwards to ${FUSEKI_URL}/<dataset>/data?graph=... with the auth header attached.

server is the nginx container's Docker-internal hostname — do not use localhost.

Environment Variables

Variable	Default	Description
PORT	8080	Host port WebVOWL is accessible on
FUSEKI_AUTH_HEADER	(required for Fuseki)	Full Authorization header value sent to Fuseki
DOCKER_NETWORK	semantic-web	External Docker network name
FUSEKI_URL	http://fuseki:3030	Fuseki base URL (Docker-internal)

DOCKER_NETWORK and FUSEKI_URL rarely need to change. FUSEKI_AUTH_HEADER is the one you'll actually configure.

Development Reference

npm scripts

Command	Description
npm run dev	Live-reloading dev server
npm run build	Production build into deploy/
npm run build:dev	Development build
npm run release	Production build, removing benchmark data
npm run zip	Build and package into a zip file
npm test	Run unit tests (Vitest)
npm run lint	Lint source with ESLint 9

Hot-swap deploy (no Docker rebuild)

For code-only changes, skip the full image rebuild:

npm run release && docker cp deploy/. webvowl-server-1:/usr/share/nginx/html/

If you modify package.json or docker-compose.yml, do a full rebuild instead:

docker compose build --no-cache && docker compose up -d

Notes

SVG export and CSS: To export the VOWL visualization as SVG, all CSS styles must be inlined into the SVG. If you change vowl.css, update the inlined styles accordingly. The tool for this is in util/VowlCssToD3RuleConverter/ — see its README.

Submodule: OWL2VOWL is pinned to a specific fork commit via a git submodule. Run git submodule update --init on fresh clones, and again after pulling if the submodule pointer has advanced.