!ENAPSO

ENAPSO Graph Database client is an easy-to-use tool to perform SPARQL query and update statements against your knowledge graphs or ontologies stored in your graph database. It can be used with any Node.js application.

As of now, ENAPSO Graph Database Client supports the following graph databases:

- Ontotext GraphDB
- Apache Jena Fuseki
- Stardog
- QLever 🆕 First Node.js package to support QLever!

More graph databases will be supported added in the future.

In addition to authentication (Basic and JWT), the client handles prefixes, handles errors, and transforms SPARQL result bindings into CSV and TSV files as well as JSON result sets that can be easily processed in JavaScript.

🚀 QLever Support - Industry First!

ENAPSO is proud to be the first Node.js package to provide comprehensive support for QLever, the high-performance SPARQL engine developed at the University of Freiburg. Our QLever integration includes:

- Advanced Query Features: Support for QLever's unique useQleverBinding option that provides total count information even when using LIMIT and OFFSET clauses
- Dynamic Access Token Management: Exclusive setAccessToken() method for runtime token updates (QLever-only feature)
- Access Token Authentication: Seamless integration with QLever's access token-based authentication system
- High Performance: Optimized for QLever's exceptional query performance capabilities

The following tools you also might find useful:

- ENAPSO Graph Database Admin: Enables you to perform administrative and monitoring operations against your graph databases, such as importing and exporting ontologies or knowledge graphs and utilizing the graph database's special features.
- ENAPSO Command Line Interface for Graph Databases: Enables you to perform numerous scriptable operations on graph databases, e.g. for monitoring and testing, CI/CD pipelines or backup and restore.

🛠️ Installation

``
npm i @innotrade/enapso-graphdb-client --save
`

Create the connection with graph database

`javascript
const { EnapsoGraphDBClient } = require('@innotrade/enapso-graphdb-client');

let graphDBEndpoint = new EnapsoGraphDBClient.Endpoint({
baseURL: 'http://localhost:7200',
repository: 'Test',
triplestore: 'graphdb', // 'graphdb' or 'fuseki' or 'stardog' or 'qlever'
prefixes: [
{
prefix: 'entest',
iri: 'http://ont.enapso.com/test#'
}
],
transform: 'toCSV'
});
`

$3

| Parameter | Type | Description | Values |
| --------------------- | ---------------- | ---------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------- |
| baseURL(required) | String | Pass the URL in which graph database is running. | |
| repository(required) | String | Pass the name of the repository or database of the graph databases with which you want to create a connection. | |
| prefixes(required) | Array of objects | Pass the prefix and its IRI as an object which will be used in the SPARQL query to perform crud operations. | |
| triplestore(optional) | String | Pass the name of the graph database with which you want to create a connection by default it creates a connection with Ontotext GraphDB. | ('graphdb' , 'stardog' , 'fuseki' , 'qlever') |
| transform(optional) | String | Pass the type in which you want to show the result of SPARQL query by default it shows the result in JSON format. | ('toJSON', 'toCSV' , 'toTSV') |

📋 Features

| Feature | Description | Ontotext GraphDB | Apache Jena Fuseki | Stardog | QLever |
| -------------------- | ------------------------------------------------------------------ | ---------------- | ------------------ | ------- | ------ |
| Login | Authenticate user against the graph database | ✔ | ✘ | ✔ | ✘* |
| Query | To retrieve the information from graph database using SPARQL query | ✔ | ✔ | ✔ | ✔ |
| Update | To update the triples in the graph database | ✔ | ✔ | ✔ | ✔** |
| setAccessToken | Set access token to perform update. | ✘ | ✘ | ✘ | ✔ |

*QLever uses access tokens instead of traditional login
**Requires access token for update operations

Authentication

Authenticate against the graph database :

 

`
graphDBEndpoint.login('admin','root').then((result) => {
console.log(result);
})
.catch((err) => {
console.log(err);
});
`







Query

Query the graph database:

`
graphDBEndpoint
.query(
'select *
where {
?class rdf:type owl:Class
filter(regex(str(?class), "http://ont.enapso.com/test#TestClass", "i")) .
}',
{ transform: 'toJSON' }
)
.then((result) => {
console.log(
'Read the classes name:\n' + JSON.stringify(result, null, 2)
);
})
.catch((err) => {
console.log(err);
});
`







Update

Update the graph database:

`
graphDBEndpoint
.update(
insert data {
graph {
entest:TestClass rdf:type owl:Class}
}
)
.then((result) => {
console.log('inserted a class :\n' + JSON.stringify(result, null, 2));
})
.catch((err) => {
console.log(err);
});
``







setAccessToken

Set or update access token dynamically (QLever only):

`javascript
// Set or update access token dynamically
qleverEndpoint.setAccessToken('your-new-access-token');

// Now you can perform operations with the new token
qleverEndpoint
.query('SELECT * WHERE { ?s ?p ?o } LIMIT 5')
.then((result) => {
console.log('Query with new token:', JSON.stringify(result, null, 2));
});
`










$3

QLever's unique useQleverBinding feature allows you to get the total count of results even when using LIMIT and OFFSET:

`javascript
qleverEndpoint
.query(
SELECT ?subject ?predicate ?object WHERE {
?subject ?predicate ?object
} LIMIT 10 OFFSET 20,
{
transform: 'toJSON',
useQleverBinding: true // Get total count with pagination
}
)
.then((result) => {
console.log('Query results:', JSON.stringify(result, null, 2));
// Result will include both the limited results and total count
})
.catch((err) => {
console.log(err);
});
``

📖 Documentation

View the documentation for further usage examples.

🧪 Testing

Tutorial to run the Test suite against the graph database.

😎 Contributing

Contributing is more than just coding. You can support the project in many ways. We will be happy to collaborate with you and we are looking forward to commonly making semantics and knowledge graph technologies available for your projects.

Details of how you can help the project are described in the CONTRIBUTING.md
document.

🧑‍🏫 Contributors

💬 Bugs and Feature Requests

Do you have a bug report or a feature request?

Please feel free to add a new
issue or write to us in discussion: Any questions and suggestions are welcome.

🧾 License

This project is licensed under the Apache 2.0 License. See the LICENSE file for more
details.