oslc-server

An OSLC 3.0 server reference implementation built with Node.js and Express. It uses the oslc-service Express middleware for OSLC operations, backed by Apache Jena Fuseki for RDF persistence.

oslc-server only provides OSLC and LDP REST services. It does not provide any additional application capabilities or UI. The REST services are intended to be used programmatically, possibly to support an OSLC3 test server and reference implementation, or by the oslc-browser sample application.

Many thanks to Steve Speicher and Sam Padgett for their valuable contribution to LDP and the LDP middleware upon which this service is built.

Architecture

oslc-server is built from several modules in the oslc4js workspace:

• oslc-server -- Express application entry point and static assets
• oslc-service -- Express middleware providing OSLC 3.0 services, built on ldp-service
• ldp-service -- Express middleware implementing the W3C LDP protocol (GET, HEAD, PUT, POST, DELETE for RDF resources and containers)
• ldp-service-jena -- Storage backend that persists RDF graphs in Apache Jena Fuseki
• storage-service -- Abstract storage interface shared by all backends

The Express app (src/app.ts) serves static files, then mounts oslc-service which delegates to ldp-service for all LDP operations. Configuration is read from config.json with environment variable overrides.

Running

Prerequisites

• Node.js v22 or later
• Apache Jena Fuseki running with a dataset configured

Setup

Install dependencies from the workspace root:

$ npm install

Build the TypeScript source:

$ cd oslc-server
$ npm run build

Configuration

Edit config.json to match your environment:

{
  "scheme": "http",
  "host": "localhost",
  "port": 3001,
  "context": "/",
  "jenaURL": "http://localhost:3030/univ/"
}

• port -- The port to listen on (3001 by default, to avoid conflict with ldp-app on 3000)
• context -- The URL path prefix for OSLC/LDP resources
• jenaURL -- The Fuseki dataset endpoint URL

Start

Start Fuseki with your dataset, then:

$ npm start

The server starts on the configured port. Use a REST client or the ldp-app visualization to interact with resources.

REST API

oslc-server exposes OSLC 3.0 discovery services and W3C LDP resource management. All RDF endpoints accept and produce text/turtle, application/ld+json, and application/rdf+xml.

OSLC Discovery

The ServiceProviderCatalog is an LDP BasicContainer at {context}/oslc (e.g. http://localhost:3000/oslc), initialized at startup from config/catalog-template.ttl.

• GET /oslc -- Returns the catalog with ldp:contains links to ServiceProviders
• POST /oslc -- Creates a new ServiceProvider. Body is Turtle with at least dcterms:title. Use Slug header to suggest a URI segment. Returns 201 with Location
• GET /oslc/{sp} -- Returns a ServiceProvider with its services, creation factories, and dialogs
• DELETE /oslc/{sp} -- Deletes a ServiceProvider and removes it from the catalog

Example -- create a ServiceProvider:

POST /oslc HTTP/1.1
Content-Type: text/turtle
Slug: myproject

@prefix dcterms: <http://purl.org/dc/terms/> .
<> dcterms:title "My Project" .

OSLC Delegated UI

• GET /dialog/create?shape={shapeURI}&creation={creationURI} -- Returns an HTML creation form generated from the ResourceShape. On submit, POSTs Turtle to the creation URI and responds via the OSLC delegated UI protocol (postMessage or windowName)
• GET /compact?uri={resourceURI} -- Resource preview. Accept: text/html returns a small preview HTML fragment; Accept: text/turtle returns an oslc:Compact RDF description with a smallPreview link

LDP Resources and Containers

All resources are managed under the configured context path. LDP supports RDF Source resources and containers (BasicContainer, DirectContainer).

• GET /{path} -- Returns the resource or container. Supports If-None-Match/ETag conditional requests. Containers support Prefer header to control containment and membership triples
• HEAD /{path} -- Same as GET without the body. Returns ETag, Content-Type, Link, and Allow headers
• POST /{container} -- Creates a new resource in the container. Use Slug header to suggest a URI. Returns 201 with Location. For DirectContainers, automatically adds membership triples
• PUT /{resource} -- Updates an existing RDF Source (not containers). Requires If-Match with the current ETag. Can also create a resource at a specific URI
• DELETE /{path} -- Deletes the resource and cleans up container membership (ldp:contains for BasicContainers, hasMemberRelation for DirectContainers)
• OPTIONS /{path} -- Returns Allow and Link headers describing supported methods and interaction model

Static Assets

• public/ -- Favicon, stylesheets, usage documentation
• dialog/ -- OSLC delegated UI dialogs (creation and selection)
• example/ -- Sample Turtle data files

License

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.