Endpoint federation

Warning

This project was a proof of concept and is not intended to be used in production. We recommand to use GraphDB instead to experiment with FedX.

This project creates a federated endpoint using FedX.

That way you can get a single endpoint that is able to query multiple SPARQL endpoints.

Quick start

Configure your endpoints in the app/config.ttl file.

You can have some examples here: https://rdf4j.org/documentation/programming/federation/#member-configuration

Run the server using the following command:

./gradlew run

The endpoint will be available at: http://localhost:8080/sparql

POST query

You will need to set the following headers:

• Accept: application/sparql-results+json or application/sparql-results+xml
• Content-Type: x-www-form-urlencoded

Example of query using curl:

curl -X POST \
  'http://localhost:8080/sparql' \
  -H 'Accept: application/sparql-results+json' \
  -H 'Content-Type: application/x-www-form-urlencoded' \
  --data 'query=SELECT DISTINCT * WHERE { ?s ?p ?o } LIMIT 100'

GET query

You will need to set the following headers:

• Accept: application/sparql-results+json or application/sparql-results+xml
• Content-Type: x-www-form-urlencoded

The query needs to be urlencoded and passed to the query parameter. For big queries, you should use the POST method.

Example of query using curl:

curl 'http://localhost:8080/sparql?query=SELECT%20*%20WHERE%20%7B%20%3Fs%20%3Fp%20%3Fo%20%7D%20LIMIT%2010' \
  -H 'Accept: application/sparql-results+json' \
  -H 'Content-Type: application/x-www-form-urlencoded'