sparql_query.md

Get JSON from a SPARQL query

To get JSON results from a SPARQL query you can make a HTTP request to https://query.wikidata.org/sparql?query={SPARQL}&format=json, which with wikidata-sdk can be done like this:

// Make sure you initialize wbk with a sparqlEndpoint
const wbk = require('wikibase-sdk')({
  instance: 'https://my-wikibase-instan.se',
  sparqlEndpoint: 'https://query.my-wikibase-instan.se/sparql'
})
const sparql = 'SELECT * WHERE { ?s ?p ? o } LIMIT 10'
const url = wbk.sparqlQuery(sparql)
// request the generated URL with your favorite HTTP request library
request({ method: 'GET', url })

You can then simplify the response using wbk.simplify.sparqlResults.

Example

Exemple taken from inventaire SPARQL queries (here written using ES6 template string capabilities)

const authorQid = 'Q535'
const sparql = `
SELECT ?work ?date WHERE {
  ?work wdt:P50 wd:${authorQid} .
  OPTIONAL {
    ?work wdt:P577 ?date .
  }
}
`
const url = wbk.sparqlQuery(sparql)
// => https://query.my-wikibase-instan.se/sparql?format=json&query=%0APREFIX%20wd%3A%20%3Chttp%3A%2F%2Fwww.wikidata.org%2Fentity%2F%3E%0APREFIX%20wdt%3A%20%3Chttp%3A%2F%2Fwww.wikidata.org%2Fprop%2Fdirect%2F%3E%0A%0ASELECT%20%3Fwork%20%3Fdate%20WHERE%20%7B%0A%20%20%3Fwork%20wdt%3AP50%20wd%3AQ535%20.%0A%20%20OPTIONAL%20%7B%0A%20%20%20%20%3Fwork%20wdt%3AP577%20%3Fdate%20.%0A%20%20%7D%0A%7D%0A

Querying this url should return a big collection of objects with work and date attributes corresponding to all Mr Q535's works, that you might want to simplify before working with it.

Pre-baked queries

• Get entities reverse claims

POST request

If the generated request URL gets too long, you can make a POST request instead

const [ url, body ]  = wbk.sparqlQuery(sparql).split('?')
request({ method: 'POST', url, body })