import logging
from flask import (
Blueprint, current_app, jsonify, request, make_response,
render_template, send_file)
from rdflib import URIRef
from rdflib.plugin import PluginException
from lakesuperior import env
from lakesuperior.api import query as query_api
from lakesuperior.dictionaries.namespaces import ns_collection as nsc
from lakesuperior.dictionaries.namespaces import ns_mgr as nsm
# Query endpoint. raw SPARQL queries exposing the underlying layout can be made
# available. Also convenience methods that allow simple lookups based on simple
# binary comparisons should be added. Binary lookups—maybe?
# N.B All data sources are read-only for this endpoint.
logger = logging.getLogger(__name__)
rdfly = env.app_globals.rdfly
query = Blueprint('query', __name__)
[docs]@query.route('/term_search', methods=['GET', 'POST'])
def term_search():
"""
Search by entering a search term and optional property and comparison term.
"""
operands = (
('_id', 'Matches Term'),
('=', 'Is Equal To'),
('!=', 'Is Not Equal To'),
('<', 'Is Less Than'),
('>', 'Is Greater Than'),
('<=', 'Is Less Than Or Equal To'),
('>=', 'Is Greater Than Or Equal To'),
)
qres = term_list = []
if request.method == 'POST':
terms = request.json.get('terms', {})
or_logic = request.json.get('logic', 'and') == 'or'
logger.info('Form: {}'.format(request.json))
logger.info('Terms: {}'.format(terms))
logger.info('Logic: {}'.format(or_logic))
qres = query_api.term_query(terms, or_logic)
rsp = [
uri.replace(nsc['fcres'], request.host_url.rstrip('/') + '/ldp')
for uri in qres]
return jsonify(rsp), 200
else:
return render_template(
'term_search.html', operands=operands, qres=qres, nsm=nsm)
[docs]@query.route('/sparql', methods=['GET', 'POST'])
def sparql():
"""
Perform a direct SPARQL query on the underlying triplestore.
:param str qry: SPARQL query string.
"""
accept_mimetypes = {
'text/csv': 'csv',
'application/sparql-results+json': 'json',
'application/sparql-results+xml': 'xml',
}
if request.method == 'GET':
return render_template('sparql_query.html', nsm=nsm)
else:
if request.mimetype == 'application/sparql-query':
qstr = request.stream.read()
else:
qstr = request.form['query']
logger.debug('Query: {}'.format(qstr))
match = request.accept_mimetypes.best_match(accept_mimetypes.keys())
fmt = (
accept_mimetypes[match] if match
else request.accept_mimetypes.best)
try:
out_stream = query_api.sparql_query(qstr, fmt)
except PluginException:
return (
'Unable to serialize results into format {}'.format(fmt), 406)
return send_file(out_stream, mimetype=fmt), 200