HeFQUIN-FRAW

HeFQUIN-FRAW allows to execute random walks across federations of SPARQL endpoints that also support random walks, like endpoints running RAW x Passage.

HeFQUIN-FRAW is an extension of HeFQUIN. This repository started as a clone of the HeFQUIN github repository. Below, you can find information regarding the HeFQUIN base engine.

HeFQUIN

HeFQUIN is a query federation engine for heterogeneous federations of graph data sources (e.g, federated knowledge graphs) that is currently under development by the Semantic Web research group at Linköping University.

For detailed information about HeFQUIN, refer to the Website at https://liusemweb.github.io/, where you can find * a list of the features of HeFQUIN, * a detailed user documentation, * a list of related research publications, * information for contributors, and more.

Quick Guide

This version of HeFQUIN-FRAW relies on FedUP for the source selection step. You need to install FedUP beforehand.

Using HeFQUIN-FRAW as a Service

• Starting the service using the command line program

  • Clone the hefquin-fraw repository and checkout the "provenance" branch. bash git clone git@github.com:GDD-Nantes/HeFQUIN-FRAW.git cd HeFQUIN-FRAW git pull
  • Generate the JAR file bash mvn install -Dmaven.test.skip -f pom.xml
  • Start the server using the hefquin-server binary. bash ./bin/hefquin-server \ --port=8080 \ --path="" \ --federationDescription fedshop200.ttl \ --confDescr ExampleEngineConf.ttl \ --frawConfDescr f200_UOJ.ttl where
  • the --port argument specifies the port at which the service shall listen and
  • the --path argument specifies the custom URL path serving the different endpoints
  • the --federationDescription argument refers to a file (e.g., fedshop200.ttl) that contains an RDF-based description of your federation.
  • the --confDescr argument refers to a file (e.g., f200_eval.ttl) that contains an RDF-based description of the engine used to process queries sent to the SPARQL endpoint.
  • the --frawConfDescr argument refers to a file (e.g., f200_UOJ.ttl) that contains an RDF-based description of the engine used to process queries sent to the sampling endpoint.

  This configuration assumes a federation of 200 endpoints as described in FedShop that all offer to process queries with random walks. The easiest way to set up such a federation is using RAW x Passage.

• Interacting with the HeFQUIN-FRAW Service

  • After starting up the HeFQUIN-FRAW service, you can first test it test by opening http://localhost:8080/ in a Web browser (assuming that you have started the service at port 8080 and without specifying a custom path).
  • You can interact with the service like with a SPARQL endpoint (the endpoint should be exposed at http://localhost:8080/sparql). For instance, by using the command-line tool curl, you may execute the following command to issue the query in a file called ExampleQuery.rq. bash curl -X POST http://localhost:8080/sparql --data-binary @query.sparql -H 'Content-Type: application/sparql-query'
  • Our documentation page about interacting with a HeFQUIN service provides more details.
  • Moreover, you can read more about the queries and query features that you can use.