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from opcua import ua |
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class EventResult(object): |
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""" |
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To be sent to clients for every events from server |
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""" |
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def __init__(self): |
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self.server_handle = None |
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def __str__(self): |
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return "EventResult({})".format([str(k) + ":" + str(v) for k, v in self.__dict__.items()]) |
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__repr__ = __str__ |
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def get_event_props_as_fields_dict(self): |
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""" |
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convert all properties of the EventResult class to a dict of variants |
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""" |
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field_vars = {} |
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for key, value in vars(self).items(): |
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if not key.startswith("__") and key is not "server_handle": |
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field_vars[key] = ua.Variant(value) |
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return field_vars |
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def event_obj_from_event_fields(select_clauses, fields): |
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result = EventResult() |
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for idx, sattr in enumerate(select_clauses): |
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if len(sattr.BrowsePath) == 0: |
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setattr(result, sattr.AttributeId.name, fields[idx].Value) |
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else: |
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setattr(result, sattr.BrowsePath[0].Name, fields[idx].Value) |
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return result |
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def get_filter_from_event_type(eventtype): |
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evfilter = ua.EventFilter() |
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evfilter.SelectClauses = select_clauses_from_evtype(eventtype) |
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evfilter.WhereClause = where_clause_from_evtype(eventtype) |
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return evfilter |
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def select_clauses_from_evtype(evtype): |
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clauses = [] |
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for prop in get_event_properties_from_type_node(evtype): |
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op = ua.SimpleAttributeOperand() |
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op.TypeDefinitionId = evtype.nodeid |
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op.AttributeId = ua.AttributeIds.Value |
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op.BrowsePath = [prop.get_browse_name()] |
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clauses.append(op) |
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return clauses |
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def where_clause_from_evtype(evtype): |
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cf = ua.ContentFilter() |
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el = ua.ContentFilterElement() |
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# operands can be ElementOperand, LiteralOperand, AttributeOperand, SimpleAttribute |
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op = ua.SimpleAttributeOperand() |
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op.TypeDefinitionId = evtype.nodeid |
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op.BrowsePath.append(ua.QualifiedName("EventType", 0)) |
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op.AttributeId = ua.AttributeIds.Value |
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el.FilterOperands.append(op) |
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for subtypeid in [st.nodeid for st in get_node_subtypes(evtype)]: |
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op = ua.LiteralOperand() |
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op.Value = ua.Variant(subtypeid) |
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el.FilterOperands.append(op) |
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el.FilterOperator = ua.FilterOperator.InList |
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cf.Elements.append(el) |
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return cf |
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def get_node_subtypes(node, nodes=None): |
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if nodes is None: |
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nodes = [node] |
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for child in node.get_children(refs=ua.ObjectIds.HasSubtype): |
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nodes.append(child) |
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get_node_subtypes(child, nodes) |
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return nodes |
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def get_event_properties_from_type_node(node): |
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properties = [] |
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curr_node = node |
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while True: |
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properties.extend(curr_node.get_properties()) |
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if curr_node.nodeid.Identifier == ua.ObjectIds.BaseEventType: |
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break |
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parents = curr_node.get_referenced_nodes(refs=ua.ObjectIds.HasSubtype, direction=ua.BrowseDirection.Inverse, includesubtypes=False) |
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if len(parents) != 1: # Something went wrong |
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return None |
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curr_node = parents[0] |
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return properties |
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