Oxigraph RDF Store as a serverless SPARQL endpoint for Deno Deploy

This simple Deno Deploy application serves a serverless in-memory Oxigraph RDF store, allowing users to execute SPARQL SELECT queries against a specified Turtle file.

Features

• Fetches and loads a Turtle file into an in-memory Oxigraph store
• Allows executing SPARQL SELECT queries against the store via a GET request.

Requirements

• Deno 1.x
• Deno Deploy (for deployment)

Installation

1. Ensure you have Deno installed on your machine. Visit deno.land for installation instructions.
2. Clone the repository or download the source code to your local machine.

Configuration

You can customize the Turtle file URL and base URI by setting the following environment variables:

• TURTLE_FILE_URL: The URL of the Turtle file to load into the Oxigraph store.
• BASE_URI: The base URI for the RDF data in the Turtle file.

You can set these variables in a .env file or directly in the environment before running the application.

Usage

1. Run the application locally using the following command:

deno run --allow-net --allow-env index.js

2. Access the API by sending a GET request to http://localhost:8000?query={your_query} with your desired SPARQL SELECT query.

Deployment

Deploy the application using Deno Deploy:

1. Create a new project on Deno Deploy and link it to your repository.
2. Set the deployment settings to use index.js as the entry point.
3. Deploy the application.

Usage Reference

Execute a SPARQL SELECT query

Send a GET request with the query parameter containing the SPARQL SELECT query.

GET /?query={query}

Parameters

• query (required) - The SPARQL SELECT query to execute against the in-memory Oxigraph store.

Response

Returns a JSON object containing the query results and any errors during the query execution.

{
  "query": "string",
  "results": [
    {
      "key": "value"
    }
  ],
  "error": "string (optional)",
  "stack": "string (optional, only in development environment)"
}

Demo

A demo deployment of this application is available at the following URL:

https://serverless-sparql.deno.dev/

This demo deployment loads a simple RDF dataset from the example Turtle file available at https://www.yamaml.org/examples/tbbt_v02.ttl.

Example Query

To execute a SPARQL SELECT query against the demo deployment, simply append your desired query as a URL-encoded parameter to the base URL. For example, the following query retrieves all distinct subject, predicate, and object triples from the RDF store:

SELECT DISTINCT ?s ?p ?o WHERE { ?s ?p ?o }

Access the query results by sending a GET request to the demo deployment URL with the query parameter:

https://serverless-sparql.deno.dev/?query=SELECT%20DISTINCT%20?s%20?p%20?o%20WHERE%20%7B%20?s%20?p%20?o%20%7D

Alternatively, you can use a tool like curl to send a GET request to the demo deployment:

curl "https://serverless-sparql.deno.dev/" \
  --get \
  --data-urlencode "query=SELECT DISTINCT ?s ?p ?o WHERE { ?s ?p ?o }"

License

This project is licensed under the MIT License.