async def where_clause_from_evtype(evtypes):
cf = ua.ContentFilter()
el = ua.ContentFilterElement()
# operands can be ElementOperand, LiteralOperand, AttributeOperand, SimpleAttribute
# Create a clause where the generate event type property EventType
# must be a subtype of events in evtypes argument
# the first operand is the attribute event type
op = ua.SimpleAttributeOperand()
# op.TypeDefinitionId = evtype.nodeid
op.BrowsePath.append(ua.QualifiedName("EventType", 0))
op.AttributeId = ua.AttributeIds.Value
el.FilterOperands.append(op)
# now create a list of all subtypes we want to accept
subtypes = []
for evtype in evtypes:
for st in await get_node_subtypes(evtype):
subtypes.append(st.nodeid)
subtypes = list(set(subtypes)) # remove duplicates
for subtypeid in subtypes:
op = ua.LiteralOperand()
op.Value = ua.Variant(subtypeid)
el.FilterOperands.append(op)
el.FilterOperator = ua.FilterOperator.InList
cf.Elements.append(el)
return cf
def test_where_clause():
cf = ua.ContentFilter()
el = ua.ContentFilterElement()
op = ua.SimpleAttributeOperand()
op.BrowsePath.append(ua.QualifiedName("property", 2))
el.FilterOperands.append(op)
for i in range(10):
op = ua.LiteralOperand()
op.Value = ua.Variant(i)
el.FilterOperands.append(op)
el.FilterOperator = ua.FilterOperator.InList
cf.Elements.append(el)
wce = WhereClauseEvaluator(logging.getLogger(__name__), None, cf)
ev = BaseEvent()
ev._freeze = False
ev.property = 3
assert wce.eval(ev)
