asyncua.common.subscription.Subscription._call_datachange() - 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 20:14 UTC

Subscription._call_datachange() A

↳ Parent: asyncua.common.subscription

Complexity

Conditions

Size

Total Lines	14
Code Lines	13

Duplication

Lines	0
Ratio	0 %

Importance

Changes

Metric	Value
cc	5
eloc	13
nop	2
dl	0
loc	14
rs	9.2833
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 to data change events of one or 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 an integer value for single Nodes. If the creation of the subscription fails an
        `UaStatusCodeError` is raised.
        If multiple Nodes are supplied, a List of integers or ua.StatusCode objects is returned. A list of
        StatusCode objects are returned to indicate that the subscription has failed (no exception will be
        raised 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 - no 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 to data change events of one or 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 an integer value for single Nodes. If the creation of the subscription fails an
159			`UaStatusCodeError` is raised.
160			If multiple Nodes are supplied, a List of integers or ua.StatusCode objects is returned. A list of
161			StatusCode objects are returned to indicate that the subscription has failed (no exception will be
162			raised in this case).
163			If more control is necessary the `create_monitored_items` method can be used directly.
164
165			:param nodes: One Node or an Iterable of Nodes
166			:param attr: The Node attribute you want to subscribe to
167			:param queuesize: 0 or 1 for default queue size (shall be 1 - no queuing), n for FIFO queue
168			:return: Handle for changing/cancelling of the subscription
169			"""
170			return await self._subscribe(nodes, attr, queuesize=queuesize)
171
172			async def subscribe_events(self,
173			sourcenode: Node = ua.ObjectIds.Server,
174			evtypes=ua.ObjectIds.BaseEventType,
175			evfilter=None,
176			queuesize=0) -> int:
177			"""
178			Subscribe to events from a node. Default node is Server node.
179			In most servers the server node is the only one you can subscribe to.
180			If evtypes is not provided, evtype defaults to BaseEventType.
181			If evtypes is a list or tuple of custom event types, the events will be filtered to the supplied types.
182			A handle (integer value) is returned which can be used to modify/cancel the subscription.
183
184			:param sourcenode:
185			:param evtypes:
186			:param evfilter:
187			:param queuesize: 0 for default queue size, 1 for minimum queue size, n for FIFO queue,
188			MaxUInt32 for max queue size
189			:return: Handle for changing/cancelling of the subscription
190			"""
191			sourcenode = Node(self.server, sourcenode)
192			if evfilter is None:
193			if not type(evtypes) in (list, tuple):
194			evtypes = [evtypes]
195			evtypes = [Node(self.server, evtype) for evtype in evtypes]
196			evfilter = await get_filter_from_event_type(evtypes)
197			return await self._subscribe(sourcenode, ua.AttributeIds.EventNotifier, evfilter, queuesize=queuesize)
198
199			async def _subscribe(self, nodes: Union[Node, Iterable[Node]],
200			attr, mfilter=None, queuesize=0) -> Union[int, List[Union[int, ua.StatusCode]]]:
201			"""
202			Private low level method for subscribing.
203			:param nodes: One Node or an Iterable og Nodes.
204			:param attr: ua.AttributeId
205			:param mfilter: MonitoringFilter
206			:param queuesize: queue size
207			:return: Integer handle or if multiple Nodes were given a List of Integer handles/ua.StatusCode
208			"""
209			is_list = True
210			if isinstance(nodes, collections.Iterable):
211			nodes = list(nodes)
212			else:
213			nodes = [nodes]
214			is_list = False
215			# Create List of MonitoredItemCreateRequest
216			mirs = []
217			for node in nodes:
218			mir = self._make_monitored_item_request(node, attr, mfilter, queuesize)
219			mirs.append(mir)
220			# Await MonitoredItemCreateResult
221			mids = await self.create_monitored_items(mirs)
222			if is_list:
223			# Return results for multiple nodes
224			return mids
225			# Check and return result for single node (raise `UaStatusCodeError` if subscription failed)
226			if type(mids[0]) == ua.StatusCode:
227			mids[0].check()
228			return mids[0]
229
230			def _make_monitored_item_request(self, node: Node, attr, mfilter, queuesize) -> ua.MonitoredItemCreateRequest:
231			rv = ua.ReadValueId()
232			rv.NodeId = node.nodeid
233			rv.AttributeId = attr
234			# rv.IndexRange //We leave it null, then the entire array is returned
235			mparams = ua.MonitoringParameters()
236			self._client_handle += 1
237			mparams.ClientHandle = self._client_handle
238			mparams.SamplingInterval = self.parameters.RequestedPublishingInterval
239			mparams.QueueSize = queuesize
240			mparams.DiscardOldest = True
241			if mfilter:
242			mparams.Filter = mfilter
243			mir = ua.MonitoredItemCreateRequest()
244			mir.ItemToMonitor = rv
245			mir.MonitoringMode = ua.MonitoringMode.Reporting
246			mir.RequestedParameters = mparams
247			return mir
248
249			async def create_monitored_items(self, monitored_items) -> List[Union[int, ua.StatusCode]]:
250			"""
251			low level method to have full control over subscription parameters.
252			Client handle must be unique since it will be used as key for internal registration of data.
253			"""
254			params = ua.CreateMonitoredItemsParameters()
255			params.SubscriptionId = self.subscription_id
256			params.ItemsToCreate = monitored_items
257			params.TimestampsToReturn = ua.TimestampsToReturn.Both
258			# insert monitored item into map to avoid notification arrive before result return
259			# server_handle is left as None in purpose as we don't get it yet.
260			for mi in monitored_items:
261			data = SubscriptionItemData()
262			data.client_handle = mi.RequestedParameters.ClientHandle
263			data.node = Node(self.server, mi.ItemToMonitor.NodeId)
264			data.attribute = mi.ItemToMonitor.AttributeId
265			# TODO: Either use the filter from request or from response.
266			# Here it uses from request, in modify it uses from response
267			data.mfilter = mi.RequestedParameters.Filter
268			self._monitored_items[mi.RequestedParameters.ClientHandle] = data
269			results = await self.server.create_monitored_items(params)
270			mids = []
271			# process result, add server_handle, or remove it if failed
272			for idx, result in enumerate(results):
273			mi = params.ItemsToCreate[idx]
274			if not result.StatusCode.is_good():
275			del self._monitored_items[mi.RequestedParameters.ClientHandle]
276			mids.append(result.StatusCode)
277			continue
278			data = self._monitored_items[mi.RequestedParameters.ClientHandle]
279			data.server_handle = result.MonitoredItemId
280			mids.append(result.MonitoredItemId)
281			return mids
282
283			async def unsubscribe(self, handle: Union[int, List[int]]):
284			"""
285			Unsubscribe from datachange or events using the handle returned while subscribing.
286			If you delete the subscription, you do not need to unsubscribe.
287			:param handle: The handle that was returned when subscribing to the node/nodes
288			"""
289			handles = [handle] if type(handle) is int else handle
290			params = ua.DeleteMonitoredItemsParameters()
291			params.SubscriptionId = self.subscription_id
292			params.MonitoredItemIds = handles
293			results = await self.server.delete_monitored_items(params)
294			results[0].check()
295			for k, v in self._monitored_items.items():
296			if v.server_handle in handles:
297			del (self._monitored_items[k])
298			return
299
300			async def modify_monitored_item(self, handle: int, new_samp_time, new_queuesize=0, mod_filter_val=-1):
301			"""
302			Modify a monitored item.
303			:param handle: Handle returned when originally subscribing
304			:param new_samp_time: New wanted sample time
305			:param new_queuesize: New wanted queuesize, default is 0
306			:param mod_filter_val: New deadband filter value
307			:return: Return a Modify Monitored Item Result
308			"""
309			# Find the monitored item in the monitored item registry.
310			item_to_change = next(item for item in self._monitored_items.values() if item.server_handle == handle)
311			if not item_to_change:
312			raise ValueError('The monitored item was not found.')
313			if mod_filter_val is None:
314			mod_filter = None
315			elif mod_filter_val < 0:
316			mod_filter = item_to_change.mfilter
317			else:
318			mod_filter = ua.DataChangeFilter()
319			# send notification when status or value change
320			mod_filter.Trigger = ua.DataChangeTrigger(1)
321			mod_filter.DeadbandType = 1
322			# absolute float value or from 0 to 100 for percentage deadband
323			mod_filter.DeadbandValue = mod_filter_val
324			modif_item = ua.MonitoredItemModifyRequest()
325			modif_item.MonitoredItemId = handle
326			modif_item.RequestedParameters = self._modify_monitored_item_request(
327			new_queuesize, new_samp_time, mod_filter, item_to_change.client_handle
328			)
329			params = ua.ModifyMonitoredItemsParameters()
330			params.SubscriptionId = self.subscription_id
331			params.ItemsToModify.append(modif_item)
332			results = await self.server.modify_monitored_items(params)
333			item_to_change.mfilter = results[0].FilterResult
334			return results
335
336			def _modify_monitored_item_request(self, new_queuesize, new_samp_time, mod_filter, client_handle):
337			req_params = ua.MonitoringParameters()
338			req_params.ClientHandle = client_handle
339			req_params.QueueSize = new_queuesize
340			req_params.Filter = mod_filter
341			req_params.SamplingInterval = new_samp_time
342			return req_params
343
344			def deadband_monitor(self, var, deadband_val, deadbandtype=1, queuesize=0, attr=ua.AttributeIds.Value):
345			"""
346			Method to create a subscription with a Deadband Value.
347			Default deadband value type is absolute.
348			Return a handle which can be used to unsubscribe
349			:param var: Variable to which you want to subscribe
350			:param deadband_val: Absolute float value
351			:param deadbandtype: Default value is 1 (absolute), change to 2 for percentage deadband
352			:param queuesize: Wanted queue size, default is 1
353			:param attr: Attribute ID
354			"""
355			deadband_filter = ua.DataChangeFilter()
356			# send notification when status or value change
357			deadband_filter.Trigger = ua.DataChangeTrigger(1)
358			deadband_filter.DeadbandType = deadbandtype
359			# absolute float value or from 0 to 100 for percentage deadband
360			deadband_filter.DeadbandValue = deadband_val
361			return self._subscribe(var, attr, deadband_filter, queuesize)
362

FreeOpcUa / opcua-asyncio

Pull Request — master (#45)

Subscription._call_datachange() A

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