asyncua.common.subscription.Subscription.unsubscribe() - Code Metrics - Inspection of "WIP Refactored Subscription" - FreeOpcUa/opcua-asyncio - Measure and Improve Code Quality continuously with Scrutinizer

Passed

Pull Request — master (#45)

unknown

created 2019-05-02 14:59 UTC

Subscription.unsubscribe() A

↳ Parent: asyncua.common.subscription

Complexity

Conditions

Size

Total Lines	16
Code Lines	11

Duplication

Lines	0
Ratio	0 %

Importance

Changes

Metric	Value
cc	4
eloc	11
nop	2
dl	0
loc	16
rs	9.85
c	0
b	0
f	0

"""
high level interface to subscriptions
"""
import asyncio
import logging
import collections
from typing import Union, List, Iterable

from asyncua import ua
from .events import Event, get_filter_from_event_type
from .node import Node


class SubHandler:
    """
    Subscription Handler. To receive events from server for a subscription
    This class is just a sample class. Whatever class having these methods can be used
    """

    def datachange_notification(self, node, val, data):
        """
        called for every datachange notification from server
        """
        pass

    def event_notification(self, event):
        """
        called for every event notification from server
        """
        pass

    def status_change_notification(self, status):
        """
        called for every status change notification from server
        """
        pass


class SubscriptionItemData:
    """
    To store useful data from a monitored item.
    """

    def __init__(self):
        self.node = None
        self.client_handle = None
        self.server_handle = None
        self.attribute = None
        self.mfilter = None


class DataChangeNotif:
    """
    To be send to clients for every datachange notification from server.
    """

    def __init__(self, subscription_data, monitored_item):
        self.monitored_item = monitored_item
        self.subscription_data = subscription_data

    def __str__(self):
        return f"DataChangeNotification({self.subscription_data}, {self.monitored_item})"

    __repr__ = __str__


class Subscription:
    """
    Subscription object returned by Server or Client objects.
    The object represent a subscription to an opc-ua server.
    This is a high level class, especially `subscribe_data_change` and `subscribe_events methods`.
    If more control is necessary look at code and/or use `create_monitored_items method`.
    :param server: `InternalSession` or `UAClient`
    """

    def __init__(self, server, params: ua.CreateSubscriptionParameters, handler: SubHandler, loop=None):
        self.loop = loop or asyncio.get_event_loop()
        self.logger = logging.getLogger(__name__)
        self.server = server
        self._client_handle = 200
        self._handler: SubHandler = handler
        self.parameters: ua.CreateSubscriptionParameters = params  # move to data class
        self._monitored_items = {}
        self.subscription_id = None

    async def init(self):
        response = await self.server.create_subscription(self.parameters, callback=self.publish_callback)
        self.subscription_id = response.SubscriptionId  # move to data class
        self.logger.info('Subscription created %s', self.subscription_id)

    def publish_callback(self, publish_result: ua.PublishResult):
        """
        Handle `PublishResult` callback.
        """
        self.logger.info("Publish callback called with result: %s", publish_result)
        if publish_result.NotificationMessage.NotificationData is not None:
            for notif in publish_result.NotificationMessage.NotificationData:
                if isinstance(notif, ua.DataChangeNotification):
                    self._call_datachange(notif)
                elif isinstance(notif, ua.EventNotificationList):
                    self._call_event(notif)
                elif isinstance(notif, ua.StatusChangeNotification):
                    self._call_status(notif)
                else:
                    self.logger.warning("Notification type not supported yet for notification %s", notif)
        else:
            self.logger.warning("NotificationMessage is None.")

    async def delete(self):
        """
        Delete subscription on server. This is automatically done by Client and Server classes on exit.
        """
        results = await self.server.delete_subscriptions([self.subscription_id])
        results[0].check()

    def _call_datachange(self, datachange: ua.DataChangeNotification):
        for item in datachange.MonitoredItems:
            if item.ClientHandle not in self._monitored_items:
                self.logger.warning("Received a notification for unknown handle: %s", item.ClientHandle)
                continue
            data = self._monitored_items[item.ClientHandle]
            if hasattr(self._handler, "datachange_notification"):
                event_data = DataChangeNotif(data, item)
                try:
                    self._handler.datachange_notification(data.node, item.Value.Value.Value, event_data)
                except Exception:
                    self.logger.exception("Exception calling data change handler")
            else:
                self.logger.error("DataChange subscription created but handler has no datachange_notification method")

    def _call_event(self, eventlist: ua.EventNotificationList):
        for event in eventlist.Events:
            data = self._monitored_items[event.ClientHandle]
            result = Event.from_event_fields(data.mfilter.SelectClauses, event.EventFields)
            result.server_handle = data.server_handle
            if hasattr(self._handler, "event_notification"):
                try:
                    self._handler.event_notification(result)
                except Exception:
                    self.logger.exception("Exception calling event handler")
            else:
                self.logger.error("Event subscription created but handler has no event_notification method")

    def _call_status(self, status: ua.StatusChangeNotification):
        try:
            self._handler.status_change_notification(status.Status)
        except Exception:
            self.logger.exception("Exception calling status change handler")

    async def subscribe_data_change(self,
                                    nodes: Union[Node, Iterable[Node]],
                                    attr=ua.AttributeIds.Value,
                                    queuesize=0) -> Union[int, List[Union[int, ua.StatusCode]]]:
        """
        Subscribe for data change events for one ore multiple nodes.
        The default attribute used for the subscription is `Value`.
        Return value is a handle which can be used to modify/cancel the subscription.
        The handle is either an integer value for single Nodes. If the subscription failes an `UaStatusCodeError`
        will be raises.
        If multiple Nodes were supplied a List of integers or ua.StatusCode objects is returned. StatusCode objects
        are returned to indicate that the subscription has failed (no exception will be raises in this case).
        If more control is necessary the `create_monitored_items` method can be used directly.

        :param nodes: One Node or an Iterable of Nodes
        :param attr: The Node attribute you want to subscribe to
        :param queuesize: 0 or 1 for default queue size (shall be 1 - noe queuing), n for FIFO queue
        :return: Handle for changing/cancelling of the subscription
        """
        return await self._subscribe(nodes, attr, queuesize=queuesize)

    async def subscribe_events(self,
                               sourcenode: Node = ua.ObjectIds.Server,
                               evtypes=ua.ObjectIds.BaseEventType,
                               evfilter=None,
                               queuesize=0) -> int:
        """
        Subscribe to events from a node. Default node is Server node.
        In most servers the server node is the only one you can subscribe to.
        If evtypes is not provided, evtype defaults to BaseEventType.
        If evtypes is a list or tuple of custom event types, the events will be filtered to the supplied types.
        A handle (integer value) is returned which can be used to modify/cancel the subscription.

        :param sourcenode:
        :param evtypes:
        :param evfilter:
        :param queuesize: 0 for default queue size, 1 for minimum queue size, n for FIFO queue,
        MaxUInt32 for max queue size
        :return: Handle for changing/cancelling of the subscription
        """
        sourcenode = Node(self.server, sourcenode)
        if evfilter is None:
            if not type(evtypes) in (list, tuple):
                evtypes = [evtypes]
            evtypes = [Node(self.server, evtype) for evtype in evtypes]
            evfilter = await get_filter_from_event_type(evtypes)
        return await self._subscribe(sourcenode, ua.AttributeIds.EventNotifier, evfilter, queuesize=queuesize)

    async def _subscribe(self, nodes: Union[Node, Iterable[Node]],
                         attr, mfilter=None, queuesize=0) -> Union[int, List[Union[int, ua.StatusCode]]]:
        """
        Private low level method for subscribing.
        :param nodes: One Node or an Iterable og Nodes.
        :param attr: ua.AttributeId
        :param mfilter: MonitoringFilter
        :param queuesize: queue size
        :return: Integer handle or if multiple Nodes were given a List of Integer handles/ua.StatusCode
        """
        is_list = True
        if isinstance(nodes, collections.Iterable):
            nodes = list(nodes)
        else:
            nodes = [nodes]
            is_list = False
        # Create List of MonitoredItemCreateRequest
        mirs = []
        for node in nodes:
            mir = self._make_monitored_item_request(node, attr, mfilter, queuesize)
            mirs.append(mir)
        # Await MonitoredItemCreateResult
        mids = await self.create_monitored_items(mirs)
        if is_list:
            # Return results for multiple nodes
            return mids
        # Check and return result for single node (raise `UaStatusCodeError` if subscription failed)
        if type(mids[0]) == ua.StatusCode:
            mids[0].check()
        return mids[0]

    def _make_monitored_item_request(self, node: Node, attr, mfilter, queuesize) -> ua.MonitoredItemCreateRequest:
        rv = ua.ReadValueId()
        rv.NodeId = node.nodeid
        rv.AttributeId = attr
        # rv.IndexRange //We leave it null, then the entire array is returned
        mparams = ua.MonitoringParameters()
        self._client_handle += 1
        mparams.ClientHandle = self._client_handle
        mparams.SamplingInterval = self.parameters.RequestedPublishingInterval
        mparams.QueueSize = queuesize
        mparams.DiscardOldest = True
        if mfilter:
            mparams.Filter = mfilter
        mir = ua.MonitoredItemCreateRequest()
        mir.ItemToMonitor = rv
        mir.MonitoringMode = ua.MonitoringMode.Reporting
        mir.RequestedParameters = mparams
        return mir

    async def create_monitored_items(self, monitored_items) -> List[Union[int, ua.StatusCode]]:
        """
        low level method to have full control over subscription parameters.
        Client handle must be unique since it will be used as key for internal registration of data.
        """
        params = ua.CreateMonitoredItemsParameters()
        params.SubscriptionId = self.subscription_id
        params.ItemsToCreate = monitored_items
        params.TimestampsToReturn = ua.TimestampsToReturn.Both
        # insert monitored item into map to avoid notification arrive before result return
        # server_handle is left as None in purpose as we don't get it yet.
        for mi in monitored_items:
            data = SubscriptionItemData()
            data.client_handle = mi.RequestedParameters.ClientHandle
            data.node = Node(self.server, mi.ItemToMonitor.NodeId)
            data.attribute = mi.ItemToMonitor.AttributeId
            # TODO: Either use the filter from request or from response.
            #  Here it uses from request, in modify it uses from response
            data.mfilter = mi.RequestedParameters.Filter
            self._monitored_items[mi.RequestedParameters.ClientHandle] = data
        results = await self.server.create_monitored_items(params)
        mids = []
        # process result, add server_handle, or remove it if failed
        for idx, result in enumerate(results):
            mi = params.ItemsToCreate[idx]
            if not result.StatusCode.is_good():
                del self._monitored_items[mi.RequestedParameters.ClientHandle]
                mids.append(result.StatusCode)
                continue
            data = self._monitored_items[mi.RequestedParameters.ClientHandle]
            data.server_handle = result.MonitoredItemId
            mids.append(result.MonitoredItemId)
        return mids

    async def unsubscribe(self, handle: Union[int, List[int]]):
        """
        Unsubscribe from datachange or events using the handle returned while subscribing.
        If you delete the subscription, you do not need to unsubscribe.
        :param handle: The handle that was returned when subscribing to the node/nodes
        """
        handles = [handle] if type(handle) is int else handle
        params = ua.DeleteMonitoredItemsParameters()
        params.SubscriptionId = self.subscription_id
        params.MonitoredItemIds = handles
        results = await self.server.delete_monitored_items(params)
        results[0].check()
        for k, v in self._monitored_items.items():
            if v.server_handle in handles:
                del (self._monitored_items[k])
                return

    async def modify_monitored_item(self, handle: int, new_samp_time, new_queuesize=0, mod_filter_val=-1):
        """
        Modify a monitored item.
        :param handle: Handle returned when originally subscribing
        :param new_samp_time: New wanted sample time
        :param new_queuesize: New wanted queuesize, default is 0
        :param mod_filter_val: New deadband filter value
        :return: Return a Modify Monitored Item Result
        """
        # Find the monitored item in the monitored item registry.
        item_to_change = next(item for item in self._monitored_items.values() if item.server_handle == handle)
        if not item_to_change:
            raise ValueError('The monitored item was not found.')
        if mod_filter_val is None:
            mod_filter = None
        elif mod_filter_val < 0:
            mod_filter = item_to_change.mfilter
        else:
            mod_filter = ua.DataChangeFilter()
            # send notification when status or value change
            mod_filter.Trigger = ua.DataChangeTrigger(1)
            mod_filter.DeadbandType = 1
            # absolute float value or from 0 to 100 for percentage deadband
            mod_filter.DeadbandValue = mod_filter_val
        modif_item = ua.MonitoredItemModifyRequest()
        modif_item.MonitoredItemId = handle
        modif_item.RequestedParameters = self._modify_monitored_item_request(
            new_queuesize, new_samp_time, mod_filter, item_to_change.client_handle
        )
        params = ua.ModifyMonitoredItemsParameters()
        params.SubscriptionId = self.subscription_id
        params.ItemsToModify.append(modif_item)
        results = await self.server.modify_monitored_items(params)
        item_to_change.mfilter = results[0].FilterResult
        return results

    def _modify_monitored_item_request(self, new_queuesize, new_samp_time, mod_filter, client_handle):
        req_params = ua.MonitoringParameters()
        req_params.ClientHandle = client_handle
        req_params.QueueSize = new_queuesize
        req_params.Filter = mod_filter
        req_params.SamplingInterval = new_samp_time
        return req_params

    def deadband_monitor(self, var, deadband_val, deadbandtype=1, queuesize=0, attr=ua.AttributeIds.Value):
        """
        Method to create a subscription with a Deadband Value.
        Default deadband value type is absolute.
        Return a handle which can be used to unsubscribe
        :param var: Variable to which you want to subscribe
        :param deadband_val: Absolute float value
        :param deadbandtype: Default value is 1 (absolute), change to 2 for percentage deadband
        :param queuesize: Wanted queue size, default is 1
        :param attr: Attribute ID
        """
        deadband_filter = ua.DataChangeFilter()
        # send notification when status or value change
        deadband_filter.Trigger = ua.DataChangeTrigger(1)
        deadband_filter.DeadbandType = deadbandtype
        # absolute float value or from 0 to 100 for percentage deadband
        deadband_filter.DeadbandValue = deadband_val
        return self._subscribe(var, attr, deadband_filter, queuesize)


1			"""
2			high level interface to subscriptions
3			"""
4			import asyncio
5			import logging
6			import collections
7			from typing import Union, List, Iterable
8
9			from asyncua import ua
10			from .events import Event, get_filter_from_event_type
11			from .node import Node
12
13
14			class SubHandler:
15			"""
16			Subscription Handler. To receive events from server for a subscription
17			This class is just a sample class. Whatever class having these methods can be used
18			"""
19
20			def datachange_notification(self, node, val, data):
21			"""
22			called for every datachange notification from server
23			"""
24			pass
25
26			def event_notification(self, event):
27			"""
28			called for every event notification from server
29			"""
30			pass
31
32			def status_change_notification(self, status):
33			"""
34			called for every status change notification from server
35			"""
36			pass
37
38
39			class SubscriptionItemData:
40			"""
41			To store useful data from a monitored item.
42			"""
43
44			def __init__(self):
45			self.node = None
46			self.client_handle = None
47			self.server_handle = None
48			self.attribute = None
49			self.mfilter = None
50
51
52			class DataChangeNotif:
53			"""
54			To be send to clients for every datachange notification from server.
55			"""
56
57			def __init__(self, subscription_data, monitored_item):
58			self.monitored_item = monitored_item
59			self.subscription_data = subscription_data
60
61			def __str__(self):
62			return f"DataChangeNotification({self.subscription_data}, {self.monitored_item})"
63
64			__repr__ = __str__
65
66
67			class Subscription:
68			"""
69			Subscription object returned by Server or Client objects.
70			The object represent a subscription to an opc-ua server.
71			This is a high level class, especially `subscribe_data_change` and `subscribe_events methods`.
72			If more control is necessary look at code and/or use `create_monitored_items method`.
73			:param server: `InternalSession` or `UAClient`
74			"""
75
76			def __init__(self, server, params: ua.CreateSubscriptionParameters, handler: SubHandler, loop=None):
77			self.loop = loop or asyncio.get_event_loop()
78			self.logger = logging.getLogger(__name__)
79			self.server = server
80			self._client_handle = 200
81			self._handler: SubHandler = handler
82			self.parameters: ua.CreateSubscriptionParameters = params # move to data class
83			self._monitored_items = {}
84			self.subscription_id = None
85
86			async def init(self):
87			response = await self.server.create_subscription(self.parameters, callback=self.publish_callback)
88			self.subscription_id = response.SubscriptionId # move to data class
89			self.logger.info('Subscription created %s', self.subscription_id)
90
91			def publish_callback(self, publish_result: ua.PublishResult):
92			"""
93			Handle `PublishResult` callback.
94			"""
95			self.logger.info("Publish callback called with result: %s", publish_result)
96			if publish_result.NotificationMessage.NotificationData is not None:
97			for notif in publish_result.NotificationMessage.NotificationData:
98			if isinstance(notif, ua.DataChangeNotification):
99			self._call_datachange(notif)
100			elif isinstance(notif, ua.EventNotificationList):
101			self._call_event(notif)
102			elif isinstance(notif, ua.StatusChangeNotification):
103			self._call_status(notif)
104			else:
105			self.logger.warning("Notification type not supported yet for notification %s", notif)
106			else:
107			self.logger.warning("NotificationMessage is None.")
108
109			async def delete(self):
110			"""
111			Delete subscription on server. This is automatically done by Client and Server classes on exit.
112			"""
113			results = await self.server.delete_subscriptions([self.subscription_id])
114			results[0].check()
115
116			def _call_datachange(self, datachange: ua.DataChangeNotification):
117			for item in datachange.MonitoredItems:
118			if item.ClientHandle not in self._monitored_items:
119			self.logger.warning("Received a notification for unknown handle: %s", item.ClientHandle)
120			continue
121			data = self._monitored_items[item.ClientHandle]
122			if hasattr(self._handler, "datachange_notification"):
123			event_data = DataChangeNotif(data, item)
124			try:
125			self._handler.datachange_notification(data.node, item.Value.Value.Value, event_data)
126			except Exception:
127			self.logger.exception("Exception calling data change handler")
128			else:
129			self.logger.error("DataChange subscription created but handler has no datachange_notification method")
130
131			def _call_event(self, eventlist: ua.EventNotificationList):
132			for event in eventlist.Events:
133			data = self._monitored_items[event.ClientHandle]
134			result = Event.from_event_fields(data.mfilter.SelectClauses, event.EventFields)
135			result.server_handle = data.server_handle
136			if hasattr(self._handler, "event_notification"):
137			try:
138			self._handler.event_notification(result)
139			except Exception:
140			self.logger.exception("Exception calling event handler")
141			else:
142			self.logger.error("Event subscription created but handler has no event_notification method")
143
144			def _call_status(self, status: ua.StatusChangeNotification):
145			try:
146			self._handler.status_change_notification(status.Status)
147			except Exception:
148			self.logger.exception("Exception calling status change handler")
149
150			async def subscribe_data_change(self,
151			nodes: Union[Node, Iterable[Node]],
152			attr=ua.AttributeIds.Value,
153			queuesize=0) -> Union[int, List[Union[int, ua.StatusCode]]]:
154			"""
155			Subscribe for data change events for one ore multiple nodes.
156			The default attribute used for the subscription is `Value`.
157			Return value is a handle which can be used to modify/cancel the subscription.
158			The handle is either an integer value for single Nodes. If the subscription failes an `UaStatusCodeError`
159			will be raises.
160			If multiple Nodes were supplied a List of integers or ua.StatusCode objects is returned. StatusCode objects
161			are returned to indicate that the subscription has failed (no exception will be raises in this case).
162			If more control is necessary the `create_monitored_items` method can be used directly.
163
164			:param nodes: One Node or an Iterable of Nodes
165			:param attr: The Node attribute you want to subscribe to
166			:param queuesize: 0 or 1 for default queue size (shall be 1 - noe queuing), n for FIFO queue
167			:return: Handle for changing/cancelling of the subscription
168			"""
169			return await self._subscribe(nodes, attr, queuesize=queuesize)
170
171			async def subscribe_events(self,
172			sourcenode: Node = ua.ObjectIds.Server,
173			evtypes=ua.ObjectIds.BaseEventType,
174			evfilter=None,
175			queuesize=0) -> int:
176			"""
177			Subscribe to events from a node. Default node is Server node.
178			In most servers the server node is the only one you can subscribe to.
179			If evtypes is not provided, evtype defaults to BaseEventType.
180			If evtypes is a list or tuple of custom event types, the events will be filtered to the supplied types.
181			A handle (integer value) is returned which can be used to modify/cancel the subscription.
182
183			:param sourcenode:
184			:param evtypes:
185			:param evfilter:
186			:param queuesize: 0 for default queue size, 1 for minimum queue size, n for FIFO queue,
187			MaxUInt32 for max queue size
188			:return: Handle for changing/cancelling of the subscription
189			"""
190			sourcenode = Node(self.server, sourcenode)
191			if evfilter is None:
192			if not type(evtypes) in (list, tuple):
193			evtypes = [evtypes]
194			evtypes = [Node(self.server, evtype) for evtype in evtypes]
195			evfilter = await get_filter_from_event_type(evtypes)
196			return await self._subscribe(sourcenode, ua.AttributeIds.EventNotifier, evfilter, queuesize=queuesize)
197
198			async def _subscribe(self, nodes: Union[Node, Iterable[Node]],
199			attr, mfilter=None, queuesize=0) -> Union[int, List[Union[int, ua.StatusCode]]]:
200			"""
201			Private low level method for subscribing.
202			:param nodes: One Node or an Iterable og Nodes.
203			:param attr: ua.AttributeId
204			:param mfilter: MonitoringFilter
205			:param queuesize: queue size
206			:return: Integer handle or if multiple Nodes were given a List of Integer handles/ua.StatusCode
207			"""
208			is_list = True
209			if isinstance(nodes, collections.Iterable):
210			nodes = list(nodes)
211			else:
212			nodes = [nodes]
213			is_list = False
214			# Create List of MonitoredItemCreateRequest
215			mirs = []
216			for node in nodes:
217			mir = self._make_monitored_item_request(node, attr, mfilter, queuesize)
218			mirs.append(mir)
219			# Await MonitoredItemCreateResult
220			mids = await self.create_monitored_items(mirs)
221			if is_list:
222			# Return results for multiple nodes
223			return mids
224			# Check and return result for single node (raise `UaStatusCodeError` if subscription failed)
225			if type(mids[0]) == ua.StatusCode:
226			mids[0].check()
227			return mids[0]
228
229			def _make_monitored_item_request(self, node: Node, attr, mfilter, queuesize) -> ua.MonitoredItemCreateRequest:
230			rv = ua.ReadValueId()
231			rv.NodeId = node.nodeid
232			rv.AttributeId = attr
233			# rv.IndexRange //We leave it null, then the entire array is returned
234			mparams = ua.MonitoringParameters()
235			self._client_handle += 1
236			mparams.ClientHandle = self._client_handle
237			mparams.SamplingInterval = self.parameters.RequestedPublishingInterval
238			mparams.QueueSize = queuesize
239			mparams.DiscardOldest = True
240			if mfilter:
241			mparams.Filter = mfilter
242			mir = ua.MonitoredItemCreateRequest()
243			mir.ItemToMonitor = rv
244			mir.MonitoringMode = ua.MonitoringMode.Reporting
245			mir.RequestedParameters = mparams
246			return mir
247
248			async def create_monitored_items(self, monitored_items) -> List[Union[int, ua.StatusCode]]:
249			"""
250			low level method to have full control over subscription parameters.
251			Client handle must be unique since it will be used as key for internal registration of data.
252			"""
253			params = ua.CreateMonitoredItemsParameters()
254			params.SubscriptionId = self.subscription_id
255			params.ItemsToCreate = monitored_items
256			params.TimestampsToReturn = ua.TimestampsToReturn.Both
257			# insert monitored item into map to avoid notification arrive before result return
258			# server_handle is left as None in purpose as we don't get it yet.
259			for mi in monitored_items:
260			data = SubscriptionItemData()
261			data.client_handle = mi.RequestedParameters.ClientHandle
262			data.node = Node(self.server, mi.ItemToMonitor.NodeId)
263			data.attribute = mi.ItemToMonitor.AttributeId
264			# TODO: Either use the filter from request or from response.
265			# Here it uses from request, in modify it uses from response
266			data.mfilter = mi.RequestedParameters.Filter
267			self._monitored_items[mi.RequestedParameters.ClientHandle] = data
268			results = await self.server.create_monitored_items(params)
269			mids = []
270			# process result, add server_handle, or remove it if failed
271			for idx, result in enumerate(results):
272			mi = params.ItemsToCreate[idx]
273			if not result.StatusCode.is_good():
274			del self._monitored_items[mi.RequestedParameters.ClientHandle]
275			mids.append(result.StatusCode)
276			continue
277			data = self._monitored_items[mi.RequestedParameters.ClientHandle]
278			data.server_handle = result.MonitoredItemId
279			mids.append(result.MonitoredItemId)
280			return mids
281
282			async def unsubscribe(self, handle: Union[int, List[int]]):
283			"""
284			Unsubscribe from datachange or events using the handle returned while subscribing.
285			If you delete the subscription, you do not need to unsubscribe.
286			:param handle: The handle that was returned when subscribing to the node/nodes
287			"""
288			handles = [handle] if type(handle) is int else handle
289			params = ua.DeleteMonitoredItemsParameters()
290			params.SubscriptionId = self.subscription_id
291			params.MonitoredItemIds = handles
292			results = await self.server.delete_monitored_items(params)
293			results[0].check()
294			for k, v in self._monitored_items.items():
295			if v.server_handle in handles:
296			del (self._monitored_items[k])
297			return
298
299			async def modify_monitored_item(self, handle: int, new_samp_time, new_queuesize=0, mod_filter_val=-1):
300			"""
301			Modify a monitored item.
302			:param handle: Handle returned when originally subscribing
303			:param new_samp_time: New wanted sample time
304			:param new_queuesize: New wanted queuesize, default is 0
305			:param mod_filter_val: New deadband filter value
306			:return: Return a Modify Monitored Item Result
307			"""
308			# Find the monitored item in the monitored item registry.
309			item_to_change = next(item for item in self._monitored_items.values() if item.server_handle == handle)
310			if not item_to_change:
311			raise ValueError('The monitored item was not found.')
312			if mod_filter_val is None:
313			mod_filter = None
314			elif mod_filter_val < 0:
315			mod_filter = item_to_change.mfilter
316			else:
317			mod_filter = ua.DataChangeFilter()
318			# send notification when status or value change
319			mod_filter.Trigger = ua.DataChangeTrigger(1)
320			mod_filter.DeadbandType = 1
321			# absolute float value or from 0 to 100 for percentage deadband
322			mod_filter.DeadbandValue = mod_filter_val
323			modif_item = ua.MonitoredItemModifyRequest()
324			modif_item.MonitoredItemId = handle
325			modif_item.RequestedParameters = self._modify_monitored_item_request(
326			new_queuesize, new_samp_time, mod_filter, item_to_change.client_handle
327			)
328			params = ua.ModifyMonitoredItemsParameters()
329			params.SubscriptionId = self.subscription_id
330			params.ItemsToModify.append(modif_item)
331			results = await self.server.modify_monitored_items(params)
332			item_to_change.mfilter = results[0].FilterResult
333			return results
334
335			def _modify_monitored_item_request(self, new_queuesize, new_samp_time, mod_filter, client_handle):
336			req_params = ua.MonitoringParameters()
337			req_params.ClientHandle = client_handle
338			req_params.QueueSize = new_queuesize
339			req_params.Filter = mod_filter
340			req_params.SamplingInterval = new_samp_time
341			return req_params
342
343			def deadband_monitor(self, var, deadband_val, deadbandtype=1, queuesize=0, attr=ua.AttributeIds.Value):
344			"""
345			Method to create a subscription with a Deadband Value.
346			Default deadband value type is absolute.
347			Return a handle which can be used to unsubscribe
348			:param var: Variable to which you want to subscribe
349			:param deadband_val: Absolute float value
350			:param deadbandtype: Default value is 1 (absolute), change to 2 for percentage deadband
351			:param queuesize: Wanted queue size, default is 1
352			:param attr: Attribute ID
353			"""
354			deadband_filter = ua.DataChangeFilter()
355			# send notification when status or value change
356			deadband_filter.Trigger = ua.DataChangeTrigger(1)
357			deadband_filter.DeadbandType = deadbandtype
358			# absolute float value or from 0 to 100 for percentage deadband
359			deadband_filter.DeadbandValue = deadband_val
360			return self._subscribe(var, attr, deadband_filter, queuesize)
361

FreeOpcUa / opcua-asyncio

Pull Request — master (#45)

Subscription.unsubscribe() A

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