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class HistoryStorageInterface(object): |
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3
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""" |
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Interface of a history backend. |
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Must be implemented by backends |
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""" |
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8
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1 |
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def new_historized_node(self, node, period, count=0): |
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""" |
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10
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Called when a new node is to be historized |
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Returns None |
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""" |
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raise NotImplementedError |
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15
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1 |
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def save_node_value(self, node, datavalue): |
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""" |
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Called when the value of a historized node has changed and should be saved in history |
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Returns None |
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""" |
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raise NotImplementedError |
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22
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1 |
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def read_node_history(self, node, start, end, nb_values): |
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""" |
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Called when a client make a history read request for a node |
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if start or end is missing then nb_values is used to limit query |
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nb_values is the max number of values to read. Ignored if 0 |
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Start time and end time are inclusive |
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Returns a list of DataValues and a continuation point which |
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29
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is None if all nodes are read or the ServerTimeStamp of the last rejected DataValue |
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""" |
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raise NotImplementedError |
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33
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1 |
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def new_historized_event(self, event, period): |
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""" |
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35
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Called when historization of events is enabled on server side |
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FIXME: we may need to store events per nodes in future... |
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37
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Returns None |
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""" |
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raise NotImplementedError |
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41
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1 |
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def save_event(self, event): |
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""" |
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Called when a new event has been generated ans should be saved in history |
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Returns None |
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""" |
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46
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raise NotImplementedError |
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47
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48
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1 |
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def read_event_history(self, start, end, evfilter): |
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49
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""" |
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50
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Called when a client make a history read request for events |
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Start time and end time are inclusive |
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Returns a list of Events and a continuation point which |
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is None if all events are read or the ServerTimeStamp of the last rejected event |
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54
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""" |
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raise NotImplementedError |
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57
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1 |
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def stop(self): |
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""" |
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Called when the server shuts down |
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Can be used to close database connections etc. |
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""" |
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raise NotImplementedError |
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FreeOpcUa /
python-opcua
