class SPARQLResource(Resource):
"""a sparql-over-http server. This resource is commonly at the
root of an http server. There is ad-hoc support for some things
beyond queries:
POST /add?context={uri} with postdata that's an nt file
GET /save?context={uri}
GET / to view stats about what's been served
POST /remove?context={uri} with postdata that's ntriples to remove, context is optional
todo:
DELETE /?context={uri} drop this context
"""
isLeaf = True
def __init__(self, graph):
self.graph = graph
self.stats = Stats()
def render_GET(self, request):
# see http://twistedmatrix.com/projects/web/documentation/howto/using-twistedweb.html#rendering
if request.path == '/':
if 'query' not in request.args:
return self.stats.statusPage()
return self.getQuery(request)
if request.path == '/save':
warnings.warn('Use POST for /save requests', DeprecationWarning)
return self.getSave(request)
request.setResponseCode(http.BAD_REQUEST)
return "<html>Invalid request: this is a sparql query server</html>"
def getQuery(self, request):
"""GET /?query=SELECT... returns sparql results in xml"""
query = request.args['query'][0]
log.debug("received query: %r", query)
isCount = request.getHeader('x-stat-result') == 'count'
self.stats.queries += 1
t1 = time.time()
try:
self.stats.lastQuery = query
if isCount:
count = self.graph.countQuery(query)
else:
results = self.graph.queryd(query)
except Exception, e:
self.stats.lastErrorQuery = query
self.stats.lastError = traceback.format_exc()
log.debug("query error: %s", self.stats.lastError)
raise
if not isCount:
try:
results = list(results)
count = len(results)
log.debug("got %s rows", count)
except TypeError,e:
count = 0 # this bogus value only affects the stats
def __init__(self, graph):
self.graph = graph
self.stats = Stats()