RDF Validator

Offline / command line rdf validator.

The output will be an HTML report with a list of subjects violating the rule.

Built-in rulesets

The stand-alone jar already contains a set of [DCAT-AP 1.1] (https://joinup.ec.europa.eu/asset/dcat_application_profile/description) SPARQL rules checking:

• mandatory classes and properties
• recommended properties
• the use of the EU Publication Office's MDR Authority lists (controlled vocabularies)
• best practices (e.g. language tags on literals)

Requirements

Running the validator only requires a Java 8 runtime, there are no other components to install (no database, no RDF triple store, no application server...)

Binaries can be found in dist/bin, compiling from source requires a Java 8 JDK and Maven.

Notes

• Based on rdf4j (formerly known as Sesame) and other Java open source libraries.
• Logging uses SLF4J.

Rulesets

A ruleset is just a set of text files, each containing one SPARQL SELECT query returning violations.

The first line of the SPARQL query can be a comment (starting with a '#'), this will then be used as a title in the HTML output report.

Example:

# Catalog missing mandatory title

PREFIX dcat:    <http://www.w3.org/ns/dcat#>
PREFIX dcterms: <http://purl.org/dc/terms/>

SELECT ?catalog
WHERE {
    ?catalog a dcat:Catalog
    FILTER NOT EXISTS { 
        ?catalog dcterms:title ?value
    }
}

Running

Invoke with

# java -jar validator.jar -i dcat_ap_file.nt -o report.html

The input file can be RDF/XML (.xml), NTriples (.nt) or Turtle (.ttl) The output file is always an HTML file.

Use -r to specify a directory containing SPARQL rules

# java -jar validator.jar -i dcat_ap_file.nt -o report.html -r dir1 dir2

If no ruleset is specified, the built-in rulesets for DCAT-AP 1.1 (mandatory + best practices for data.gov.be) will be used. This is equivalent to

# java -jar validator.jar -i dcat_ap_file.nt -o report.html
        -r builtin://dcatap11 builtin://dcatap11be

Use -D to set logging level and save the log to a file

# java -Dorg.slf4j.simpleLogger.defaultLogLevel=debug 
       -Dorg.slf4j.simpleLogger.logFile=validator.log
       -jar validator.jar