SPARQL query formatter

Question

Sometimes SPARQL code appears in URLs, as long query strings, and then it is basically a very long one-liner, often URL-encoded. Or the SPARQL contains a lot of UNIONs which have linebreaks located at the wrong places.

I am looking for a SPARQL query formatter.

Ideally, that would be a VSCode extension. However currently (Dec 2020) there exists no such extension in the VSCode marketplace.

I would also work with a command line tool (for Linux), or an online tool where users can paste in the unformatted query and receive a formatted query.

Answer 1

Answering my own question:

Wikidata has a formatter in the Wikidata Query service. I can copy my unformatted query text, paste it in the Wikidata window, and the query will be formatted.

However the "diamond symbol/icon is only enabled and only works if the query is syntactically valid, and if it has no undefined prefixes.

It does not have to be a query that the Wikidata Service actually understands. (I don't have to execute it with the Wikidata Query Service.).

command-line formatting with wdq

The same Wikidata formatting service can be called with the wdq commandline tool which is available from the debian/ubuntu repos (apt info wdq).

With the --no-execute option, this compact query will be formatted and pretty-printed:

# input / shell command
wdq -tplanet '?planet wdt:P31 wd:Q44559; wdt:P397 ?sun' --no-execute

Output

# --no-execute flag: 
# output / formatted query, with prefixes
PREFIX bd: <http://www.bigdata.com/rdf#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX schema: <http://schema.org/>
PREFIX wd: <http://www.wikidata.org/entity/>
PREFIX wdt: <http://www.wikidata.org/prop/direct/>
PREFIX wikibase: <http://wikiba.se/ontology#>
SELECT * WHERE {
    ?planet wdt:P31 wd:Q44559 .
    ?planet wdt:P397 ?sun .
    SERVICE wikibase:label {
        bd:serviceParam wikibase:language "en" .
        ?planet rdfs:label ?planetLabel .
        ?planet schema:description ?planetDescription .
    }
}

Answer 2

An excellent javascript library to format SPARQL 1.1 is sparql-formatter

it has a GitHub repository: https://github.com/sparqling/sparql-formatter

And an online playground page: https://sparql-formatter.dbcls.jp/