asyncua.server.internal_server.InternalServer.write_attribute_value() - Code Metrics - Inspection of "rename get->read and set->write many places to bet..." - FreeOpcUa/opcua-asyncio - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Pull Request — master (#184)

by Olivier

created 2020-05-09 08:06 UTC

InternalServer.write_attribute_value() A

↳ Parent: asyncua.server.internal_server

Complexity

Conditions

Size

Total Lines	6
Code Lines	2

Duplication

Lines	0
Ratio	0 %

Importance

Changes

Metric	Value
cc	1
eloc	2
nop	4
dl	0
loc	6
rs	10
c	0
b	0
f	0

"""
Internal server implementing opcu-ua interface.
Can be used on server side or to implement binary/https opc-ua servers
"""

import asyncio
from datetime import datetime, timedelta
from copy import copy
from struct import unpack_from
import os
import logging
from urllib.parse import urlparse
from typing import Coroutine

from asyncua import ua
from ..common.callback import CallbackDispatcher
from ..common.node import Node
from .history import HistoryManager
from .address_space import AddressSpace, AttributeService, ViewService, NodeManagementService, MethodService
from .subscription_service import SubscriptionService
from .standard_address_space import standard_address_space
from .users import User
from .internal_session import InternalSession

try:
    from asyncua.crypto import uacrypto
except ImportError:
    logging.getLogger(__name__).warning("cryptography is not installed, use of crypto disabled")
    uacrypto = False


class ServerDesc:
    def __init__(self, serv, cap=None):
        self.Server = serv
        self.Capabilities = cap


def default_user_manager(iserver, isession, username, password):
    """
    Default user_manager, does nothing much but check for admin
    """
    if iserver.allow_remote_admin and username in ("admin", "Admin"):
        isession.user = User.Admin
    return True


class InternalServer:
    """
    There is one `InternalServer` for every `Server`.
    """

    def __init__(self, loop: asyncio.AbstractEventLoop):
        self.loop: asyncio.AbstractEventLoop = loop
        self.logger = logging.getLogger(__name__)
        self.server_callback_dispatcher = CallbackDispatcher()
        self.endpoints = []
        self._channel_id_counter = 5
        self.allow_remote_admin = True
        self.disabled_clock = False  # for debugging we may want to disable clock that writes too much in log
        self._known_servers = {}  # used if we are a discovery server
        self.certificate = None
        self.private_key = None
        self.aspace = AddressSpace()
        self.attribute_service = AttributeService(self.aspace)
        self.view_service = ViewService(self.aspace)
        self.method_service = MethodService(self.aspace)
        self.node_mgt_service = NodeManagementService(self.aspace)
        self.asyncio_transports = []
        self.subscription_service: SubscriptionService = SubscriptionService(self.loop, self.aspace)
        self.history_manager = HistoryManager(self)
        self.user_manager = default_user_manager  # defined at the end of this file
        # create a session to use on server side
        self.isession = InternalSession(self, self.aspace, self.subscription_service, "Internal", user=User.Admin)
        self.current_time_node = Node(self.isession, ua.NodeId(ua.ObjectIds.Server_ServerStatus_CurrentTime))

    async def init(self, shelffile=None):
        await self.load_standard_address_space(shelffile)
        await self._address_space_fixes()
        await self.setup_nodes()
        await self.history_manager.init()

    async def setup_nodes(self):
        """
        Set up some nodes as defined by spec
        """
        uries = ['http://opcfoundation.org/UA/']
        ns_node = Node(self.isession, ua.NodeId(ua.ObjectIds.Server_NamespaceArray))
        await ns_node.write_value(uries)

        params = ua.WriteParameters()
        for nodeid in (ua.ObjectIds.Server_ServerCapabilities_OperationLimits_MaxNodesPerRead,
                       ua.ObjectIds.Server_ServerCapabilities_OperationLimits_MaxNodesPerHistoryReadData,
                       ua.ObjectIds.Server_ServerCapabilities_OperationLimits_MaxNodesPerHistoryReadEvents,
                       ua.ObjectIds.Server_ServerCapabilities_OperationLimits_MaxNodesPerWrite,
                       ua.ObjectIds.Server_ServerCapabilities_OperationLimits_MaxNodesPerHistoryUpdateData,
                       ua.ObjectIds.Server_ServerCapabilities_OperationLimits_MaxNodesPerHistoryUpdateEvents,
                       ua.ObjectIds.Server_ServerCapabilities_OperationLimits_MaxNodesPerMethodCall,
                       ua.ObjectIds.Server_ServerCapabilities_OperationLimits_MaxNodesPerBrowse,
                       ua.ObjectIds.Server_ServerCapabilities_OperationLimits_MaxNodesPerRegisterNodes,
                       ua.ObjectIds.Server_ServerCapabilities_OperationLimits_MaxNodesPerTranslateBrowsePathsToNodeIds,
                       ua.ObjectIds.Server_ServerCapabilities_OperationLimits_MaxNodesPerNodeManagement,
                       ua.ObjectIds.Server_ServerCapabilities_OperationLimits_MaxMonitoredItemsPerCall):
            attr = ua.WriteValue()
            attr.NodeId = ua.NodeId(nodeid)
            attr.AttributeId = ua.AttributeIds.Value
            attr.Value = ua.DataValue(ua.Variant(10000, ua.VariantType.UInt32), ua.StatusCode(ua.StatusCodes.Good))
            attr.Value.ServerTimestamp = datetime.utcnow()
            params.NodesToWrite.append(attr)
        result = await self.isession.write(params)
        result[0].check()

    async def load_standard_address_space(self, shelf_file=None):
        if shelf_file:
            is_file = (await self.loop.run_in_executor(None, os.path.isfile, shelf_file)
                       or await self.loop.run_in_executor(None, os.path.isfile, f'{shelf_file}.db'))
            if is_file:
                # import address space from shelf
                await self.loop.run_in_executor(None, self.aspace.load_aspace_shelf, shelf_file)
                return
        # import address space from code generated from xml
        standard_address_space.fill_address_space(self.node_mgt_service)
        # import address space directly from xml, this has performance impact so disabled
        # importer = xmlimporter.XmlImporter(self.node_mgt_service)
        # importer.import_xml("/path/to/python-asyncua/schemas/Opc.Ua.NodeSet2.xml", self)
        if shelf_file:
            # path was supplied, but file doesn't exist - create one for next start up
            await self.loop.run_in_executor(None, self.aspace.make_aspace_shelf, shelf_file)

    async def _address_space_fixes(self) -> Coroutine:
        """
        Looks like the xml definition of address space has some error. This is a good place to fix them
        """
        it = ua.AddReferencesItem()
        it.SourceNodeId = ua.NodeId(ua.ObjectIds.BaseObjectType)
        it.ReferenceTypeId = ua.NodeId(ua.ObjectIds.Organizes)
        it.IsForward = False
        it.TargetNodeId = ua.NodeId(ua.ObjectIds.ObjectTypesFolder)
        it.TargetNodeClass = ua.NodeClass.Object

        it2 = ua.AddReferencesItem()
        it2.SourceNodeId = ua.NodeId(ua.ObjectIds.BaseDataType)
        it2.ReferenceTypeId = ua.NodeId(ua.ObjectIds.Organizes)
        it2.IsForward = False
        it2.TargetNodeId = ua.NodeId(ua.ObjectIds.DataTypesFolder)
        it2.TargetNodeClass = ua.NodeClass.Object

        results = await self.isession.add_references([it, it2])
        for res in results:
            res.check()

    def load_address_space(self, path):
        """
        Load address space from path
        """
        self.aspace.load(path)

    def dump_address_space(self, path):
        """
        Dump current address space to path
        """
        self.aspace.dump(path)

    async def start(self):
        self.logger.info('starting internal server')
        for edp in self.endpoints:
            self._known_servers[edp.Server.ApplicationUri] = ServerDesc(edp.Server)
        await Node(self.isession, ua.NodeId(ua.ObjectIds.Server_ServerStatus_State)).write_value(ua.ServerState.Running, ua.VariantType.Int32)
        await Node(self.isession, ua.NodeId(ua.ObjectIds.Server_ServerStatus_StartTime)).write_value(datetime.utcnow())
        if not self.disabled_clock:
            self._set_current_time()

    async def stop(self):
        self.logger.info('stopping internal server')
        self.method_service.stop()
        await self.isession.close_session()
        await self.history_manager.stop()

    def _set_current_time(self):
        self.loop.create_task(self.current_time_node.write_value(datetime.utcnow()))
        self.loop.call_later(1, self._set_current_time)

    def get_new_channel_id(self):
        self._channel_id_counter += 1
        return self._channel_id_counter

    def add_endpoint(self, endpoint):
        self.endpoints.append(endpoint)

    async def get_endpoints(self, params=None, sockname=None):
        self.logger.info('get endpoint')
        if sockname:
            # return to client the ip address it has access to
            edps = []
            for edp in self.endpoints:
                edp1 = copy(edp)
                url = urlparse(edp1.EndpointUrl)
                url = url._replace(netloc=sockname[0] + ':' + str(sockname[1]))
                edp1.EndpointUrl = url.geturl()
                edps.append(edp1)
            return edps
        return self.endpoints[:]

    def find_servers(self, params):
        if not params.ServerUris:
            return [desc.Server for desc in self._known_servers.values()]
        servers = []
        for serv in self._known_servers.values():
            serv_uri = serv.Server.ApplicationUri.split(':')
            for uri in params.ServerUris:
                uri = uri.split(':')
                if serv_uri[:len(uri)] == uri:
                    servers.append(serv.Server)
                    break
        return servers

    def register_server(self, server, conf=None):
        appdesc = ua.ApplicationDescription()
        appdesc.ApplicationUri = server.ServerUri
        appdesc.ProductUri = server.ProductUri
        # FIXME: select name from client locale
        appdesc.ApplicationName = server.ServerNames[0]
        appdesc.ApplicationType = server.ServerType
        appdesc.DiscoveryUrls = server.DiscoveryUrls
        # FIXME: select discovery uri using reachability from client network
        appdesc.GatewayServerUri = server.GatewayServerUri
        self._known_servers[server.ServerUri] = ServerDesc(appdesc, conf)

    def register_server2(self, params):
        return self.register_server(params.Server, params.DiscoveryConfiguration)

    def create_session(self, name, user=User.Anonymous, external=False):
        return InternalSession(self, self.aspace, self.subscription_service, name, user=user, external=external)

    async def enable_history_data_change(self, node, period=timedelta(days=7), count=0):
        """
        Set attribute Historizing of node to True and start storing data for history
        """
        await node.write_attribute(ua.AttributeIds.Historizing, ua.DataValue(True))
        await node.set_attr_bit(ua.AttributeIds.AccessLevel, ua.AccessLevel.HistoryRead)
        await node.set_attr_bit(ua.AttributeIds.UserAccessLevel, ua.AccessLevel.HistoryRead)
        await self.history_manager.historize_data_change(node, period, count)

    async def disable_history_data_change(self, node):
        """
        Set attribute Historizing of node to False and stop storing data for history
        """
        await node.write_attribute(ua.AttributeIds.Historizing, ua.DataValue(False))
        await node.unset_attr_bit(ua.AttributeIds.AccessLevel, ua.AccessLevel.HistoryRead)
        await node.unset_attr_bit(ua.AttributeIds.UserAccessLevel, ua.AccessLevel.HistoryRead)
        await self.history_manager.dehistorize(node)

    async def enable_history_event(self, source, period=timedelta(days=7), count=0):
        """
        Set attribute History Read of object events to True and start storing data for history
        """
        event_notifier = await source.read_event_notifier()
        if ua.EventNotifier.SubscribeToEvents not in event_notifier:
            raise ua.UaError('Node does not generate events', event_notifier)
        if ua.EventNotifier.HistoryRead not in event_notifier:
            event_notifier.add(ua.EventNotifier.HistoryRead)
            await source.set_event_notifier(event_notifier)
        await self.history_manager.historize_event(source, period, count)

    async def disable_history_event(self, source):
        """
        Set attribute History Read of node to False and stop storing data for history
        """
        await source.unset_attr_bit(ua.AttributeIds.EventNotifier, ua.EventNotifier.HistoryRead)
        await self.history_manager.dehistorize(source)

    def subscribe_server_callback(self, event, handle):
        """
        Create a subscription from event to handle
        """
        self.server_callback_dispatcher.addListener(event, handle)

    def unsubscribe_server_callback(self, event, handle):
        """
        Remove a subscription from event to handle
        """
        self.server_callback_dispatcher.removeListener(event, handle)

    def write_attribute_value(self, nodeid, datavalue, attr=ua.AttributeIds.Value):
        """
        directly write datavalue to the Attribute, bypassing some checks and structure creation
        so it is a little faster
        """
        self.aspace.write_attribute_value(nodeid, attr, datavalue)

    def set_user_manager(self, user_manager):
        """
        set up a function which that will check for authorize users. Input function takes username
        and password as parameters and returns True of user is allowed access, False otherwise.
        """
        self.user_manager = user_manager

    def check_user_token(self, isession, token):
        """
        unpack the username and password for the benefit of the user defined user manager
        """
        user_name = token.UserName
        password = token.Password
        # decrypt password if we can
        if str(token.EncryptionAlgorithm) != "None":
            if not uacrypto:
                return False
            try:
                if token.EncryptionAlgorithm == "http://www.w3.org/2001/04/xmlenc#rsa-1_5":
                    raw_pw = uacrypto.decrypt_rsa15(self.private_key, password)
                elif token.EncryptionAlgorithm == "http://www.w3.org/2001/04/xmlenc#rsa-oaep":
                    raw_pw = uacrypto.decrypt_rsa_oaep(self.private_key, password)
                else:
                    self.logger.warning("Unknown password encoding %s", token.EncryptionAlgorithm)
                    return False
                length = unpack_from('<I', raw_pw)[0] - len(isession.nonce)
                password = raw_pw[4:4 + length]
                password = password.decode('utf-8')
            except Exception:
                self.logger.exception("Unable to decrypt password")
                return False
        # call user_manager
        return self.user_manager(self, isession, user_name, password)


1			"""
2			Internal server implementing opcu-ua interface.
3			Can be used on server side or to implement binary/https opc-ua servers
4			"""
5
6			import asyncio
7			from datetime import datetime, timedelta
8			from copy import copy
9			from struct import unpack_from
10			import os
11			import logging
12			from urllib.parse import urlparse
13			from typing import Coroutine
14
15			from asyncua import ua
16			from ..common.callback import CallbackDispatcher
17			from ..common.node import Node
18			from .history import HistoryManager
19			from .address_space import AddressSpace, AttributeService, ViewService, NodeManagementService, MethodService
20			from .subscription_service import SubscriptionService
21			from .standard_address_space import standard_address_space
22			from .users import User
23			from .internal_session import InternalSession
24
25			try:
26			from asyncua.crypto import uacrypto
27			except ImportError:
28			logging.getLogger(__name__).warning("cryptography is not installed, use of crypto disabled")
29			uacrypto = False
30
31
32			class ServerDesc:
33			def __init__(self, serv, cap=None):
34			self.Server = serv
35			self.Capabilities = cap
36
37
38			def default_user_manager(iserver, isession, username, password):
39			"""
40			Default user_manager, does nothing much but check for admin
41			"""
42			if iserver.allow_remote_admin and username in ("admin", "Admin"):
43			isession.user = User.Admin
44			return True
45
46
47			class InternalServer:
48			"""
49			There is one `InternalServer` for every `Server`.
50			"""
51
52			def __init__(self, loop: asyncio.AbstractEventLoop):
53			self.loop: asyncio.AbstractEventLoop = loop
54			self.logger = logging.getLogger(__name__)
55			self.server_callback_dispatcher = CallbackDispatcher()
56			self.endpoints = []
57			self._channel_id_counter = 5
58			self.allow_remote_admin = True
59			self.disabled_clock = False # for debugging we may want to disable clock that writes too much in log
60			self._known_servers = {} # used if we are a discovery server
61			self.certificate = None
62			self.private_key = None
63			self.aspace = AddressSpace()
64			self.attribute_service = AttributeService(self.aspace)
65			self.view_service = ViewService(self.aspace)
66			self.method_service = MethodService(self.aspace)
67			self.node_mgt_service = NodeManagementService(self.aspace)
68			self.asyncio_transports = []
69			self.subscription_service: SubscriptionService = SubscriptionService(self.loop, self.aspace)
70			self.history_manager = HistoryManager(self)
71			self.user_manager = default_user_manager # defined at the end of this file
72			# create a session to use on server side
73			self.isession = InternalSession(self, self.aspace, self.subscription_service, "Internal", user=User.Admin)
74			self.current_time_node = Node(self.isession, ua.NodeId(ua.ObjectIds.Server_ServerStatus_CurrentTime))
75
76			async def init(self, shelffile=None):
77			await self.load_standard_address_space(shelffile)
78			await self._address_space_fixes()
79			await self.setup_nodes()
80			await self.history_manager.init()
81
82			async def setup_nodes(self):
83			"""
84			Set up some nodes as defined by spec
85			"""
86			uries = ['http://opcfoundation.org/UA/']
87			ns_node = Node(self.isession, ua.NodeId(ua.ObjectIds.Server_NamespaceArray))
88			await ns_node.write_value(uries)
89
90			params = ua.WriteParameters()
91			for nodeid in (ua.ObjectIds.Server_ServerCapabilities_OperationLimits_MaxNodesPerRead,
92			ua.ObjectIds.Server_ServerCapabilities_OperationLimits_MaxNodesPerHistoryReadData,
93			ua.ObjectIds.Server_ServerCapabilities_OperationLimits_MaxNodesPerHistoryReadEvents,
94			ua.ObjectIds.Server_ServerCapabilities_OperationLimits_MaxNodesPerWrite,
95			ua.ObjectIds.Server_ServerCapabilities_OperationLimits_MaxNodesPerHistoryUpdateData,
96			ua.ObjectIds.Server_ServerCapabilities_OperationLimits_MaxNodesPerHistoryUpdateEvents,
97			ua.ObjectIds.Server_ServerCapabilities_OperationLimits_MaxNodesPerMethodCall,
98			ua.ObjectIds.Server_ServerCapabilities_OperationLimits_MaxNodesPerBrowse,
99			ua.ObjectIds.Server_ServerCapabilities_OperationLimits_MaxNodesPerRegisterNodes,
100			ua.ObjectIds.Server_ServerCapabilities_OperationLimits_MaxNodesPerTranslateBrowsePathsToNodeIds,
101			ua.ObjectIds.Server_ServerCapabilities_OperationLimits_MaxNodesPerNodeManagement,
102			ua.ObjectIds.Server_ServerCapabilities_OperationLimits_MaxMonitoredItemsPerCall):
103			attr = ua.WriteValue()
104			attr.NodeId = ua.NodeId(nodeid)
105			attr.AttributeId = ua.AttributeIds.Value
106			attr.Value = ua.DataValue(ua.Variant(10000, ua.VariantType.UInt32), ua.StatusCode(ua.StatusCodes.Good))
107			attr.Value.ServerTimestamp = datetime.utcnow()
108			params.NodesToWrite.append(attr)
109			result = await self.isession.write(params)
110			result[0].check()
111
112			async def load_standard_address_space(self, shelf_file=None):
113			if shelf_file:
114			is_file = (await self.loop.run_in_executor(None, os.path.isfile, shelf_file)
115			or await self.loop.run_in_executor(None, os.path.isfile, f'{shelf_file}.db'))
116			if is_file:
117			# import address space from shelf
118			await self.loop.run_in_executor(None, self.aspace.load_aspace_shelf, shelf_file)
119			return
120			# import address space from code generated from xml
121			standard_address_space.fill_address_space(self.node_mgt_service)
122			# import address space directly from xml, this has performance impact so disabled
123			# importer = xmlimporter.XmlImporter(self.node_mgt_service)
124			# importer.import_xml("/path/to/python-asyncua/schemas/Opc.Ua.NodeSet2.xml", self)
125			if shelf_file:
126			# path was supplied, but file doesn't exist - create one for next start up
127			await self.loop.run_in_executor(None, self.aspace.make_aspace_shelf, shelf_file)
128
129			async def _address_space_fixes(self) -> Coroutine:
130			"""
131			Looks like the xml definition of address space has some error. This is a good place to fix them
132			"""
133			it = ua.AddReferencesItem()
134			it.SourceNodeId = ua.NodeId(ua.ObjectIds.BaseObjectType)
135			it.ReferenceTypeId = ua.NodeId(ua.ObjectIds.Organizes)
136			it.IsForward = False
137			it.TargetNodeId = ua.NodeId(ua.ObjectIds.ObjectTypesFolder)
138			it.TargetNodeClass = ua.NodeClass.Object
139
140			it2 = ua.AddReferencesItem()
141			it2.SourceNodeId = ua.NodeId(ua.ObjectIds.BaseDataType)
142			it2.ReferenceTypeId = ua.NodeId(ua.ObjectIds.Organizes)
143			it2.IsForward = False
144			it2.TargetNodeId = ua.NodeId(ua.ObjectIds.DataTypesFolder)
145			it2.TargetNodeClass = ua.NodeClass.Object
146
147			results = await self.isession.add_references([it, it2])
148			for res in results:
149			res.check()
150
151			def load_address_space(self, path):
152			"""
153			Load address space from path
154			"""
155			self.aspace.load(path)
156
157			def dump_address_space(self, path):
158			"""
159			Dump current address space to path
160			"""
161			self.aspace.dump(path)
162
163			async def start(self):
164			self.logger.info('starting internal server')
165			for edp in self.endpoints:
166			self._known_servers[edp.Server.ApplicationUri] = ServerDesc(edp.Server)
167			await Node(self.isession, ua.NodeId(ua.ObjectIds.Server_ServerStatus_State)).write_value(ua.ServerState.Running, ua.VariantType.Int32)
168			await Node(self.isession, ua.NodeId(ua.ObjectIds.Server_ServerStatus_StartTime)).write_value(datetime.utcnow())
169			if not self.disabled_clock:
170			self._set_current_time()
171
172			async def stop(self):
173			self.logger.info('stopping internal server')
174			self.method_service.stop()
175			await self.isession.close_session()
176			await self.history_manager.stop()
177
178			def _set_current_time(self):
179			self.loop.create_task(self.current_time_node.write_value(datetime.utcnow()))
180			self.loop.call_later(1, self._set_current_time)
181
182			def get_new_channel_id(self):
183			self._channel_id_counter += 1
184			return self._channel_id_counter
185
186			def add_endpoint(self, endpoint):
187			self.endpoints.append(endpoint)
188
189			async def get_endpoints(self, params=None, sockname=None):
190			self.logger.info('get endpoint')
191			if sockname:
192			# return to client the ip address it has access to
193			edps = []
194			for edp in self.endpoints:
195			edp1 = copy(edp)
196			url = urlparse(edp1.EndpointUrl)
197			url = url._replace(netloc=sockname[0] + ':' + str(sockname[1]))
198			edp1.EndpointUrl = url.geturl()
199			edps.append(edp1)
200			return edps
201			return self.endpoints[:]
202
203			def find_servers(self, params):
204			if not params.ServerUris:
205			return [desc.Server for desc in self._known_servers.values()]
206			servers = []
207			for serv in self._known_servers.values():
208			serv_uri = serv.Server.ApplicationUri.split(':')
209			for uri in params.ServerUris:
210			uri = uri.split(':')
211			if serv_uri[:len(uri)] == uri:
212			servers.append(serv.Server)
213			break
214			return servers
215
216			def register_server(self, server, conf=None):
217			appdesc = ua.ApplicationDescription()
218			appdesc.ApplicationUri = server.ServerUri
219			appdesc.ProductUri = server.ProductUri
220			# FIXME: select name from client locale
221			appdesc.ApplicationName = server.ServerNames[0]
222			appdesc.ApplicationType = server.ServerType
223			appdesc.DiscoveryUrls = server.DiscoveryUrls
224			# FIXME: select discovery uri using reachability from client network
225			appdesc.GatewayServerUri = server.GatewayServerUri
226			self._known_servers[server.ServerUri] = ServerDesc(appdesc, conf)
227
228			def register_server2(self, params):
229			return self.register_server(params.Server, params.DiscoveryConfiguration)
230
231			def create_session(self, name, user=User.Anonymous, external=False):
232			return InternalSession(self, self.aspace, self.subscription_service, name, user=user, external=external)
233
234			async def enable_history_data_change(self, node, period=timedelta(days=7), count=0):
235			"""
236			Set attribute Historizing of node to True and start storing data for history
237			"""
238			await node.write_attribute(ua.AttributeIds.Historizing, ua.DataValue(True))
239			await node.set_attr_bit(ua.AttributeIds.AccessLevel, ua.AccessLevel.HistoryRead)
240			await node.set_attr_bit(ua.AttributeIds.UserAccessLevel, ua.AccessLevel.HistoryRead)
241			await self.history_manager.historize_data_change(node, period, count)
242
243			async def disable_history_data_change(self, node):
244			"""
245			Set attribute Historizing of node to False and stop storing data for history
246			"""
247			await node.write_attribute(ua.AttributeIds.Historizing, ua.DataValue(False))
248			await node.unset_attr_bit(ua.AttributeIds.AccessLevel, ua.AccessLevel.HistoryRead)
249			await node.unset_attr_bit(ua.AttributeIds.UserAccessLevel, ua.AccessLevel.HistoryRead)
250			await self.history_manager.dehistorize(node)
251
252			async def enable_history_event(self, source, period=timedelta(days=7), count=0):
253			"""
254			Set attribute History Read of object events to True and start storing data for history
255			"""
256			event_notifier = await source.read_event_notifier()
257			if ua.EventNotifier.SubscribeToEvents not in event_notifier:
258			raise ua.UaError('Node does not generate events', event_notifier)
259			if ua.EventNotifier.HistoryRead not in event_notifier:
260			event_notifier.add(ua.EventNotifier.HistoryRead)
261			await source.set_event_notifier(event_notifier)
262			await self.history_manager.historize_event(source, period, count)
263
264			async def disable_history_event(self, source):
265			"""
266			Set attribute History Read of node to False and stop storing data for history
267			"""
268			await source.unset_attr_bit(ua.AttributeIds.EventNotifier, ua.EventNotifier.HistoryRead)
269			await self.history_manager.dehistorize(source)
270
271			def subscribe_server_callback(self, event, handle):
272			"""
273			Create a subscription from event to handle
274			"""
275			self.server_callback_dispatcher.addListener(event, handle)
276
277			def unsubscribe_server_callback(self, event, handle):
278			"""
279			Remove a subscription from event to handle
280			"""
281			self.server_callback_dispatcher.removeListener(event, handle)
282
283			def write_attribute_value(self, nodeid, datavalue, attr=ua.AttributeIds.Value):
284			"""
285			directly write datavalue to the Attribute, bypassing some checks and structure creation
286			so it is a little faster
287			"""
288			self.aspace.write_attribute_value(nodeid, attr, datavalue)
289
290			def set_user_manager(self, user_manager):
291			"""
292			set up a function which that will check for authorize users. Input function takes username
293			and password as parameters and returns True of user is allowed access, False otherwise.
294			"""
295			self.user_manager = user_manager
296
297			def check_user_token(self, isession, token):
298			"""
299			unpack the username and password for the benefit of the user defined user manager
300			"""
301			user_name = token.UserName
302			password = token.Password
303			# decrypt password if we can
304			if str(token.EncryptionAlgorithm) != "None":
305			if not uacrypto:
306			return False
307			try:
308			if token.EncryptionAlgorithm == "http://www.w3.org/2001/04/xmlenc#rsa-1_5":
309			raw_pw = uacrypto.decrypt_rsa15(self.private_key, password)
310			elif token.EncryptionAlgorithm == "http://www.w3.org/2001/04/xmlenc#rsa-oaep":
311			raw_pw = uacrypto.decrypt_rsa_oaep(self.private_key, password)
312			else:
313			self.logger.warning("Unknown password encoding %s", token.EncryptionAlgorithm)
314			return False
315			length = unpack_from('<I', raw_pw)[0] - len(isession.nonce)
316			password = raw_pw[4:4 + length]
317			password = password.decode('utf-8')
318			except Exception:
319			self.logger.exception("Unable to decrypt password")
320			return False
321			# call user_manager
322			return self.user_manager(self, isession, user_name, password)
323

FreeOpcUa / opcua-asyncio

Pull Request — master (#184)

InternalServer.write_attribute_value() A

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