# SPARQL Endpoint for GraphQL-LD

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This is a [GraphQL-LD](https://github.com/rubensworks/graphql-ld.js) engine for executing queries against a remote _SPARQL endpoint_.

## Usage

```javascript
import {Client} from "graphql-ld";
import {QueryEngineSparqlEndpoint} from "graphql-ld-sparqlendpoint";

// Define a JSON-LD context
const context = {
  "@context": {
    "label": { "@id": "http://www.w3.org/2000/01/rdf-schema#label" }
  }
};

// Create a GraphQL-LD client based on a SPARQL endpoint
const endpoint = 'http://dbpedia.org/sparql';
const client = new Client({ context, queryEngine: new QueryEngineSparqlEndpoint(endpoint) });

// Define a query
const query = `
  query @single {
    label
  }`;

// Execute the query
const { data } = await client.query({ query });
```

## Command-line usage

If you install this package globally (`yarn global add graphql-ld-sparqlendpoint`),
then you'll have access to the `graphql-ld-sparqlendpoint` script to execute GraphQL-LD queries from the command-line as follows:

**Query based on context and query strings:**

```
$ graphql-ld-sparqlendpoint '{ "hero": "http://example.org/hero", "name": "http://example.org/name" }' '{ hero { name } }' http://dbpedia.org/sparql
```

**Query based on context and query files:**

```
$ graphql-ld-sparqlendpoint context.json query.txt http://dbpedia.org/sparql
```

## License
This software is written by [Ruben Taelman](http://rubensworks.net/).

This code is released under the [MIT license](http://opensource.org/licenses/MIT).