SPARQL API

1. Endpoints

graph	query endpoint	update endpoint
https://read-it.hum.uu.nl/item/	/sparql/item/query	/sparql/item/update
https://read-it.hum.uu.nl/vocab#	/sparql/vocab/query
https://read-it.hum.uu.nl/source/	/sparql/source/query	/sparql/source/update
https://read-it.hum.uu.nl/ontology#	/sparql/ontology/query
https://read-it.hum.uu.nl/nlp-ontology#	/sparql/nlp-ontology/query	/sparql/nlp-ontology/update

Example full url for endpoint: https://read-it.hum.uu.nl/sparql/item/query

2. Query protocol

Request

• GET request to a query endpoint.
  • Obtain the triples in the corresponding graph.
• POST request to a query endpoint.
  • Obtain query results.
  • Only the corresponding graph will be queried.
  • Request body should contain an query parameter containing SPARQL QUERY. DESCRIBE queries are not supported.
  • An Accept header can be included to specify the desired output format, see below for options.

Output formats

Accept header	Format	Applicable query types
application/sparql-results+json (default)	SPARQL 1.1 Query Results JSON Format	ASK, SELECT
application/sparql-results+xml	SPARQL 1.1 Query Results XML Format	ASK, SELECT
text/turtle	Turtle	ASK, SELECT, CONSTRUCT

Examples

Retrieve 5 sources:

cURL

curl -d "query=SELECT ?s ?p ?o WHERE {?s ?p ?o } LIMIT 5"  -X POST -H "Accept: text/turtle" https://read-it.hum.uu.nl/sparql/source/query

Python

Uses the requests package.

import requests
q = 'SELECT ?s ?p ?o WHERE {?s ?p ?o } LIMIT 5'
endpoint = 'https://read-it.hum.uu.nl/sparql/source/query'
response = requests.post(endpoint,
                         data={'query': q},
                         headers={'Accept': 'text/turtle'})
results = response.text
print(results)

3. Authentication

Make a POST request to https://read-it.hum.uu.nl/rest-auth/login/ (note the trailing slash) with your username and password in the body to obtain an authentication token.

Examples

cUrl

curl -d "username=yourusername&password=yourpassword" -X POST https:/read-it.hum.uu.nl/rest-auth/login/

Python

import requests
login = requests.post('https://read-it.hum.uu.nl/rest-auth/login/',
                      data={'username': 'yourusername',
                            'password': 'yourpassword'})
key = login.json()['key']

4. Update protocol

Request

• POST request to an update endpoint.
  • Only the corresponding graph can be updated.
  • Only specific users are allowed to UPDATE. Contact admins for information.
  • Request body should contain an update parameter containing valid SPARQL UPDATE.
  • An Authorization header should be included containing your Token <your_token>. See above.
  • The following operations are not supported, because they make no sense in the context of a single graph, or are unsafe: LOAD, CLEAR,DROP, ADD, MOVE, COPY, CREATE.

Examples

Python (includes authentication)

import requests
# Authentication
login = requests.post('https://read-it.hum.uu.nl/rest-auth/login/',
                      data={'username': 'yourusername',
                            'password': 'yourpassword'})
key = login.json()['key']

# Update
q = 'INSERT DATA { <https://read-it.hum.uu.nl/nlp-ontology#content> a <http://www.w3.org/2000/01/rdf-schema#Class> }'
endpoint = 'https://read-it.hum.uu.nl/sparql/nlp-ontology/update'
response = requests.post(endpoint,
                         data={'update': q},
                         headers={'Authorization': 'Token {}'.format(key)})
succes_msg = response.text
print(succes_msg)
print(response.status_code)