Merge pull request #1193 from FlorianLudwig/sparql-timezone

do not use current time in sparql TIMEZONE

rdflib/plugins/sparql/operators.py

@@ -492,7 +492,7 @@ def Builtin_TIMEZONE(e, ctx):
     if not dt.tzinfo:
         raise SPARQLError("datatime has no timezone: %r" % dt)
 
-    delta = dt.tzinfo.utcoffset(ctx.now)
+    delta = dt.utcoffset()
 
     d = delta.days
     s = delta.seconds

rdflib/plugins/sparql/sparql.py

@@ -220,7 +220,7 @@ def remember(self, these):
         return FrozenBindings(self.ctx, (x for x in self.items() if x[0] in these))
 
 
-class QueryContext:
+class QueryContext(object):
     """
     Query context - passed along when evaluating the query
     """
@@ -242,10 +242,16 @@ def __init__(self, graph=None, bindings=None, initBindings=None):
             self.graph = graph
 
         self.prologue = None
-        self.now = datetime.datetime.now(isodate.tzinfo.UTC)
+        self._now = None
 
         self.bnodes = collections.defaultdict(BNode)
 
+    @property
+    def now(self) -> datetime.datetime:
+        if self._now is None:
+            self._now = datetime.datetime.now(isodate.tzinfo.UTC)
+        return self._now
+
     def clone(self, bindings=None):
         r = QueryContext(
             self._dataset if self._dataset is not None else self.graph,