SubHandler.event() - Code Metrics - Inspection of "Events implementation proposal" - FreeOpcUa/python-opcua - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Pull Request — master (#161)

by Denis

created 2016-04-27 12:43 UTC

SubHandler.event() A

↳ Parent: Project

Complexity

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Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	1
CRAP Score	1.125

Metric	Value
cc	1
dl	0
loc	5
rs	9.4285
ccs	1
cts	2
cp	0.5
crap	1.125

"""
high level interface to subscriptions
"""
import time
import logging
from threading import Lock

from opcua import ua
from opcua import Node
from opcua.common import event


class SubHandler(object):
    """
    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 data_change(self, handle, node, val, attr):
        """
        Deprecated, use datachange_notification
        """
        pass

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

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

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


class EventResult(object):
    """
    To be sent to clients for every events from server
    """

    def __init__(self):
        self.server_handle = None

    def __str__(self):
        return "EventResult({})".format([str(k) + ":" + str(v) for k, v in self.__dict__.items()])
    __repr__ = __str__


class SubscriptionItemData(object):
    """
    To store usefull 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(object):
    """
    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 "DataChangeNotfication({}, {})".format(self.subscription_data, self.monitored_item)
    __repr__ = __str__


class Subscription(object):
    """
    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.
    """

    def __init__(self, server, params, handler):
        self.logger = logging.getLogger(__name__)
        self.server = server
        self._client_handle = 200
        self._handler = handler
        self.parameters = params  # move to data class
        self._monitoreditems_map = {}
        self._lock = Lock()
        self.subscription_id = None
        response = self.server.create_subscription(params, self.publish_callback)
        self.subscription_id = response.SubscriptionId  # move to data class
        self.server.publish()
        self.server.publish()

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

    def publish_callback(self, publishresult):
        self.logger.info("Publish callback called with result: %s", publishresult)
        while self.subscription_id is None:
            time.sleep(0.01)

        for notif in publishresult.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)

        ack = ua.SubscriptionAcknowledgement()
        ack.SubscriptionId = self.subscription_id
        ack.SequenceNumber = publishresult.NotificationMessage.SequenceNumber
        self.server.publish([ack])

    def _call_datachange(self, datachange):
        for item in datachange.MonitoredItems:
            with self._lock:
                if item.ClientHandle not in self._monitoreditems_map:
                    self.logger.warning("Received a notification for unknown handle: %s", item.ClientHandle)
                    continue
                data = self._monitoreditems_map[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")
            elif hasattr(self._handler, "data_change"):  # deprecated API
                self.logger.warning("data_change method is deprecated, use datachange_notification")
                try:
                    self._handler.data_change(data.server_handle, data.node, item.Value.Value.Value, data.attribute)
                except Exception:
                    self.logger.exception("Exception calling deprecated data change handler")
            else:
                self.logger.error("DataChange subscription created but handler has no datachange_notification method")

    def _call_event(self, eventlist):
        for event in eventlist.Events:
            with self._lock:
                data = self._monitoreditems_map[event.ClientHandle]
            result = EventResult()
            result.server_handle = data.server_handle
            for idx, sattr in enumerate(data.mfilter.SelectClauses):
                if len(sattr.BrowsePath) == 0:
                    setattr(result, sattr.AttributeId.name, event.EventFields[idx].Value)
                else:
                    setattr(result, sattr.BrowsePath[0].Name, event.EventFields[idx].Value)
            if hasattr(self._handler, "event_notification"):
                try:
                    self._handler.event_notification(result)
                except Exception:
                    self.logger.exception("Exception calling event handler")
            elif hasattr(self._handler, "event"):  # depcrecated API
                try:
                    self._handler.event(data.server_handle, result)
                except Exception:
                    self.logger.exception("Exception calling deprecated event handler")
            else:
                self.logger.error("Event subscription created but handler has no event_notification method")

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

    def subscribe_data_change(self, nodes, attr=ua.AttributeIds.Value):
        """
        Subscribe for data change events for a node or list of nodes.
        default attribute is Value.
        Return a handle which can be used to unsubscribe
        If more control is necessary use create_monitored_items method
        """
        return self._subscribe(nodes, attr, queuesize=0)

    def _get_node(self, nodeid):
        if isinstance(nodeid, ua.NodeId):
            node = Node(self.server, nodeid)
        elif isinstance(nodeid, Node):
            node = nodeid
        else:
            node = Node(self.server, ua.NodeId(nodeid))
        return node

    def _get_filter_from_event_type(self, eventtype):
        eventtype = self._get_node(eventtype)
        evfilter = ua.EventFilter()
        for property in event.get_event_properties_from_type_node(eventtype):
            op = ua.SimpleAttributeOperand()
            op.TypeDefinitionId = eventtype.nodeid
            op.AttributeId = ua.AttributeIds.Value
            op.BrowsePath = [property.get_browse_name()]
            evfilter.SelectClauses.append(op)
        return evfilter

    def subscribe_events(self, sourcenode=ua.ObjectIds.Server, evtype=ua.ObjectIds.BaseEventType):
        """
        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.
        Return a handle which can be used to unsubscribe
        """
        sourcenode = self._get_node(sourcenode)
        evfilter = self._get_filter_from_event_type(evtype)
        return self._subscribe(sourcenode, ua.AttributeIds.EventNotifier, evfilter)

    def _subscribe(self, nodes, attr, mfilter=None, queuesize=0):
        is_list = True
        if not type(nodes) in (list, tuple):
            is_list = False
            nodes = [nodes]
        mirs = []
        for node in nodes:
            mir = self._make_monitored_item_request(node, attr, mfilter, queuesize)
            mirs.append(mir)

        mids = self.create_monitored_items(mirs)
        if is_list:
            return mids
        if type(mids[0]) == ua.StatusCode:
            mids[0].check()
        return mids[0]

    def _make_monitored_item_request(self, node, attr, mfilter, queuesize):
        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()
        with self._lock:
            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

    def create_monitored_items(self, monitored_items):
        """
        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.Neither

        # insert monitoried 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.
        with self._lock:
            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
                data.mfilter = mi.RequestedParameters.Filter
                self._monitoreditems_map[mi.RequestedParameters.ClientHandle] = data
        results = self.server.create_monitored_items(params)
        mids = []
        # process result, add server_handle, or remove it if failed
        with self._lock:
            for idx, result in enumerate(results):
                mi = params.ItemsToCreate[idx]
                if not result.StatusCode.is_good():
                    del self._monitoreditems_map[mi.RequestedParameters.ClientHandle]
                    mids.append(result.StatusCode)
                    continue
                data = self._monitoreditems_map[mi.RequestedParameters.ClientHandle]
                data.server_handle = result.MonitoredItemId
                mids.append(result.MonitoredItemId)
        return mids

    def unsubscribe(self, handle):
        """
        unsubscribe to datachange or events using the handle returned while subscribing
        if you delete subscription, you do not need to unsubscribe
        """
        params = ua.DeleteMonitoredItemsParameters()
        params.SubscriptionId = self.subscription_id
        params.MonitoredItemIds = [handle]
        results = self.server.delete_monitored_items(params)
        results[0].check()
        with self._lock:
            for k, v in self._monitoreditems_map.items():
                if v.server_handle == handle:
                    del(self._monitoreditems_map[k])
                    return



1		"""
2		high level interface to subscriptions
3		"""
4	1	import time
5	1	import logging
6	1	from threading import Lock
7
8	1	from opcua import ua
9	1	from opcua import Node
10	1	from opcua.common import event
11
12
13	1	class SubHandler(object):
14		"""
15		Subscription Handler. To receive events from server for a subscription
16		This class is just a sample class. Whatever class having these methods can be used
17		"""
18
19	1	def data_change(self, handle, node, val, attr):
20		"""
21		Deprecated, use datachange_notification
22		"""
23		pass
24
25	1	def datachange_notification(self, node, val, data):
26		"""
27		called for every datachange notfication from server
28		"""
29		pass
30
31	1	def event_notification(self, event):
32		"""
33		called for every event notfication from server
34		"""
35		pass
36
37	1	def status_change_notification(self, status):
38		"""
39		called for every status change notfication from server
40		"""
41		pass
42
43
44	1	class EventResult(object):
45		"""
46		To be sent to clients for every events from server
47		"""
48
49	1	def __init__(self):
50	1	self.server_handle = None
51
52	1	def __str__(self):
53		return "EventResult({})".format([str(k) + ":" + str(v) for k, v in self.__dict__.items()])
54	1	__repr__ = __str__
55
56
57	1	class SubscriptionItemData(object):
58		"""
59		To store usefull data from a monitored item
60		"""
61	1	def __init__(self):
62	1	self.node = None
63	1	self.client_handle = None
64	1	self.server_handle = None
65	1	self.attribute = None
66	1	self.mfilter = None
67
68
69	1	class DataChangeNotif(object):
70		"""
71		To be send to clients for every datachange notification from server
72		"""
73	1	def __init__(self, subscription_data, monitored_item):
74	1	self.monitored_item = monitored_item
75	1	self.subscription_data = subscription_data
76
77	1	def __str__(self):
78		return "DataChangeNotfication({}, {})".format(self.subscription_data, self.monitored_item)
79	1	__repr__ = __str__
80
81
82	1	class Subscription(object):
83		"""
84		Subscription object returned by Server or Client objects.
85		The object represent a subscription to an opc-ua server.
86		This is a high level class, especially subscribe_data_change
87		and subscribe_events methods. If more control is necessary look at
88		code and/or use create_monitored_items method.
89		"""
90
91	1	def __init__(self, server, params, handler):
92	1	self.logger = logging.getLogger(__name__)
93	1	self.server = server
94	1	self._client_handle = 200
95	1	self._handler = handler
96	1	self.parameters = params # move to data class
97	1	self._monitoreditems_map = {}
98	1	self._lock = Lock()
99	1	self.subscription_id = None
100	1	response = self.server.create_subscription(params, self.publish_callback)
101	1	self.subscription_id = response.SubscriptionId # move to data class
102	1	self.server.publish()
103	1	self.server.publish()
104
105	1	def delete(self):
106		"""
107		Delete subscription on server. This is automatically done by Client and Server classes on exit
108		"""
109	1	results = self.server.delete_subscriptions([self.subscription_id])
110	1	results[0].check()
111
112	1	def publish_callback(self, publishresult):
113	1	self.logger.info("Publish callback called with result: %s", publishresult)
114	1	while self.subscription_id is None:
115	1	time.sleep(0.01)
116
117	1	for notif in publishresult.NotificationMessage.NotificationData:
118	1	if isinstance(notif, ua.DataChangeNotification):
119	1	self._call_datachange(notif)
120	1	elif isinstance(notif, ua.EventNotificationList):
121	1	self._call_event(notif)
122		elif isinstance(notif, ua.StatusChangeNotification):
123		self._call_status(notif)
124		else:
125		self.logger.warning("Notification type not supported yet for notification %s", notif)
126
127	1	ack = ua.SubscriptionAcknowledgement()
128	1	ack.SubscriptionId = self.subscription_id
129	1	ack.SequenceNumber = publishresult.NotificationMessage.SequenceNumber
130	1	self.server.publish([ack])
131
132	1	def _call_datachange(self, datachange):
133	1	for item in datachange.MonitoredItems:
134	1	with self._lock:
135	1	if item.ClientHandle not in self._monitoreditems_map:
136	1	self.logger.warning("Received a notification for unknown handle: %s", item.ClientHandle)
137	1	continue
138	1	data = self._monitoreditems_map[item.ClientHandle]
139	1	if hasattr(self._handler, "datachange_notification"):
140	1	event_data = DataChangeNotif(data, item)
141	1	try:
142	1	self._handler.datachange_notification(data.node, item.Value.Value.Value, event_data)
143		except Exception:
144		self.logger.exception("Exception calling data change handler")
145	1	elif hasattr(self._handler, "data_change"): # deprecated API
146	1	self.logger.warning("data_change method is deprecated, use datachange_notification")
147	1	try:
148	1	self._handler.data_change(data.server_handle, data.node, item.Value.Value.Value, data.attribute)
149		except Exception:
150		self.logger.exception("Exception calling deprecated data change handler")
151		else:
152		self.logger.error("DataChange subscription created but handler has no datachange_notification method")
153
154	1	def _call_event(self, eventlist):
155	1	for event in eventlist.Events:
156	1	with self._lock:
157	1	data = self._monitoreditems_map[event.ClientHandle]
158	1	result = EventResult()
159	1	result.server_handle = data.server_handle
160	1	for idx, sattr in enumerate(data.mfilter.SelectClauses):
161	1	if len(sattr.BrowsePath) == 0:
162		setattr(result, sattr.AttributeId.name, event.EventFields[idx].Value)
163		else:
164	1	setattr(result, sattr.BrowsePath[0].Name, event.EventFields[idx].Value)
165	1	if hasattr(self._handler, "event_notification"):
166	1	try:
167	1	self._handler.event_notification(result)
168		except Exception:
169		self.logger.exception("Exception calling event handler")
170		elif hasattr(self._handler, "event"): # depcrecated API
171		try:
172		self._handler.event(data.server_handle, result)
173		except Exception:
174		self.logger.exception("Exception calling deprecated event handler")
175		else:
176		self.logger.error("Event subscription created but handler has no event_notification method")
177
178	1	def _call_status(self, status):
179		try:
180		self._handler.status_change_notification(status.Status)
181		except Exception:
182		self.logger.exception("Exception calling status change handler")
183
184	1	def subscribe_data_change(self, nodes, attr=ua.AttributeIds.Value):
185		"""
186		Subscribe for data change events for a node or list of nodes.
187		default attribute is Value.
188		Return a handle which can be used to unsubscribe
189		If more control is necessary use create_monitored_items method
190		"""
191	1	return self._subscribe(nodes, attr, queuesize=0)
192
193	1	def _get_node(self, nodeid):
194	1	if isinstance(nodeid, ua.NodeId):
195		node = Node(self.server, nodeid)
196	1	elif isinstance(nodeid, Node):
197	1	node = nodeid
198		else:
199	1	node = Node(self.server, ua.NodeId(nodeid))
200	1	return node
201
202	1	def _get_filter_from_event_type(self, eventtype):
203	1	eventtype = self._get_node(eventtype)
204	1	evfilter = ua.EventFilter()
205	1	for property in event.get_event_properties_from_type_node(eventtype):
206	1	op = ua.SimpleAttributeOperand()
207	1	op.TypeDefinitionId = eventtype.nodeid
208	1	op.AttributeId = ua.AttributeIds.Value
209	1	op.BrowsePath = [property.get_browse_name()]
210	1	evfilter.SelectClauses.append(op)
211	1	return evfilter
212
213	1	def subscribe_events(self, sourcenode=ua.ObjectIds.Server, evtype=ua.ObjectIds.BaseEventType):
214		"""
215		Subscribe to events from a node. Default node is Server node.
216		In most servers the server node is the only one you can subscribe to.
217		Return a handle which can be used to unsubscribe
218		"""
219	1	sourcenode = self._get_node(sourcenode)
220	1	evfilter = self._get_filter_from_event_type(evtype)
221	1	return self._subscribe(sourcenode, ua.AttributeIds.EventNotifier, evfilter)
222
223	1	def _subscribe(self, nodes, attr, mfilter=None, queuesize=0):
224	1	is_list = True
225	1	if not type(nodes) in (list, tuple):
226	1	is_list = False
227	1	nodes = [nodes]
228	1	mirs = []
229	1	for node in nodes:
230	1	mir = self._make_monitored_item_request(node, attr, mfilter, queuesize)
231	1	mirs.append(mir)
232
233	1	mids = self.create_monitored_items(mirs)
234	1	if is_list:
235	1	return mids
236	1	if type(mids[0]) == ua.StatusCode:
237	1	mids[0].check()
238	1	return mids[0]
239
240	1	def _make_monitored_item_request(self, node, attr, mfilter, queuesize):
241	1	rv = ua.ReadValueId()
242	1	rv.NodeId = node.nodeid
243	1	rv.AttributeId = attr
244		# rv.IndexRange //We leave it null, then the entire array is returned
245	1	mparams = ua.MonitoringParameters()
246	1	with self._lock:
247	1	self._client_handle += 1
248	1	mparams.ClientHandle = self._client_handle
249	1	mparams.SamplingInterval = self.parameters.RequestedPublishingInterval
250	1	mparams.QueueSize = queuesize
251	1	mparams.DiscardOldest = True
252	1	if mfilter:
253	1	mparams.Filter = mfilter
254	1	mir = ua.MonitoredItemCreateRequest()
255	1	mir.ItemToMonitor = rv
256	1	mir.MonitoringMode = ua.MonitoringMode.Reporting
257	1	mir.RequestedParameters = mparams
258	1	return mir
259
260	1	def create_monitored_items(self, monitored_items):
261		"""
262		low level method to have full control over subscription parameters
263		Client handle must be unique since it will be used as key for internal registration of data
264		"""
265	1	params = ua.CreateMonitoredItemsParameters()
266	1	params.SubscriptionId = self.subscription_id
267	1	params.ItemsToCreate = monitored_items
268	1	params.TimestampsToReturn = ua.TimestampsToReturn.Neither
269
270		# insert monitoried item into map to avoid notification arrive before result return
271		# server_handle is left as None in purpose as we don't get it yet.
272	1	with self._lock:
273	1	for mi in monitored_items:
274	1	data = SubscriptionItemData()
275	1	data.client_handle = mi.RequestedParameters.ClientHandle
276	1	data.node = Node(self.server, mi.ItemToMonitor.NodeId)
277	1	data.attribute = mi.ItemToMonitor.AttributeId
278	1	data.mfilter = mi.RequestedParameters.Filter
279	1	self._monitoreditems_map[mi.RequestedParameters.ClientHandle] = data
280	1	results = self.server.create_monitored_items(params)
281	1	mids = []
282		# process result, add server_handle, or remove it if failed
283	1	with self._lock:
284	1	for idx, result in enumerate(results):
285	1	mi = params.ItemsToCreate[idx]
286	1	if not result.StatusCode.is_good():
287	1	del self._monitoreditems_map[mi.RequestedParameters.ClientHandle]
288	1	mids.append(result.StatusCode)
289	1	continue
290	1	data = self._monitoreditems_map[mi.RequestedParameters.ClientHandle]
291	1	data.server_handle = result.MonitoredItemId
292	1	mids.append(result.MonitoredItemId)
293	1	return mids
294
295	1	def unsubscribe(self, handle):
296		"""
297		unsubscribe to datachange or events using the handle returned while subscribing
298		if you delete subscription, you do not need to unsubscribe
299		"""
300	1	params = ua.DeleteMonitoredItemsParameters()
301	1	params.SubscriptionId = self.subscription_id
302	1	params.MonitoredItemIds = [handle]
303	1	results = self.server.delete_monitored_items(params)
304	1	results[0].check()
305	1	with self._lock:
306	1	for k, v in self._monitoreditems_map.items():
307	1	if v.server_handle == handle:
308	1	del(self._monitoreditems_map[k])
309	1	return
310
311

FreeOpcUa / python-opcua

Pull Request — master (#161)

SubHandler.event() A

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