@vdwpsmt/node-red-contrib-sparql 0.1.1
A Node-RED node for executing SPARQL queries against SPARQL endpoints using the W3C SPARQL 1.1 Protocol
node-red-contrib-sparql
A Node-RED node for executing SPARQL queries against SPARQL endpoints, implementing the W3C SPARQL 1.1 Protocol. Based on sparql-http-client.
Features
- Execute SELECT, CONSTRUCT, DESCRIBE, ASK, and UPDATE SPARQL queries
- Supports all three W3C SPARQL Protocol HTTP methods: POST (direct), POST (form-encoded), and GET
- HTTP Basic Authentication support
- Configurable query timeout
- Multiple output formats: simplified bindings, flat values, or full SPARQL JSON response
- Dynamic query and endpoint injection via incoming messages
Nodes
sparql-query
Executes a SPARQL query against a configured endpoint.
Inputs:
| Property | Type | Description |
|---|---|---|
msg.query |
string | SPARQL query (highest priority, overrides node config) |
msg.payload |
string | Used as query if msg.query is not set |
msg.endpoint |
string | Endpoint URL (overrides configured endpoint) |
Outputs:
| Property | Type | Description |
|---|---|---|
msg.payload |
array/boolean/string/object | Query results |
msg.queryType |
string | Detected query type (SELECT, CONSTRUCT, DESCRIBE, ASK, UPDATE) |
msg.sparqlQuery |
string | The executed query |
Output formats (configurable):
| Format | SELECT result | ASK result |
|---|---|---|
| JSON (simplified) | results.bindings array with type metadata |
boolean |
| JSON (flat values) | Array of { var: "value" } objects (no type info) |
boolean |
| JSON (full response) | Complete SPARQL JSON Results object | Complete response |
CONSTRUCT/DESCRIBE always return RDF text. UPDATE always returns { success: true }.
sparql-endpoint (config node)
Configures a reusable SPARQL endpoint connection.
| Property | Description |
|---|---|
| Endpoint | SPARQL endpoint URL |
| HTTP Method | POST (direct), POST (form-encoded), or GET |
| Username / Password | Optional HTTP Basic Authentication credentials |
Example
Import the example flow from examples/basic-select.json via the Node-RED import menu.
Requirements
- Node.js >= 18.0.0
- Node-RED >= 2.0.0
License
MIT
