opcua.Client.get_server_node() - Code Metrics - Inspection of "discovery implementation" - FreeOpcUa/python-opcua - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Pull Request — master (#70)

by Olivier

created 2015-12-15 10:32 UTC

opcua.Client.get_server_node() A

↳ Parent: opcua.Client

Complexity

Conditions

Size

Total Lines

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	2
CRAP Score	1

Metric	Value
dl	0
loc	2
ccs	2
cts	2
cp	1
rs	10
cc	1
crap	1

from __future__ import division  # support for python2
import os
from threading import Thread, Condition
import logging
try:
    from urllib.parse import urlparse
except ImportError:  # support for python2
    from urlparse import urlparse

from opcua import uaprotocol as ua
from opcua import BinaryClient, Node, Subscription
from opcua import utils
from opcua import uacrypto


class KeepAlive(Thread):

    """
    Used by Client to keep session opened.
    OPCUA defines timeout both for sessions and secure channel
    """

    def __init__(self, client, timeout):
        Thread.__init__(self)
        self.logger = logging.getLogger(__name__)
        if timeout == 0:  # means no timeout bu we do not trust such servers
            timeout = 360000
        self.timeout = timeout
        self.client = client
        self._dostop = False
        self._cond = Condition()

    def run(self):
        self.logger.debug("starting keepalive thread with period of %s milliseconds", self.timeout)
        server_state = self.client.get_node(ua.FourByteNodeId(ua.ObjectIds.Server_ServerStatus_State))
        while not self._dostop:
            with self._cond:
                self._cond.wait(self.timeout / 1000)
            if self._dostop:
                break
            self.logger.debug("renewing channel")
            self.client.open_secure_channel(renew=True)
            val = server_state.get_value()
            self.logger.debug("server state is: %s ", val)
        self.logger.debug("keepalive thread has stopped")

    def stop(self):
        self.logger.debug("stoping keepalive thread")
        with self._cond:
            self._cond.notify_all()
        self._dostop = True


class Client(object):

    """
    High level client to connect to an OPC-UA server.
    This class makes it easy to connect and browse address space.
    It attemps to expose as much functionality as possible
    but if you want to do to special things you will probably need
    to work with the BinaryClient object, available as self.bclient
    which offers a raw OPC-UA interface.
    """

    def __init__(self, url, timeout=1):
        """
        used url argument to connect to server.
        if you are unsure of url, write at least hostname and port
        and call get_endpoints
        timeout is the timeout to get an answer for requests to server
        public member of this call are available to be set by API users

        """
        self.logger = logging.getLogger(__name__)
        self.server_url = urlparse(url)
        self.name = "Pure Python Client"
        self.description = self.name
        self.application_uri = "urn:freeopcua:client"
        self.product_uri = "urn:freeopcua.github.no:client"
        self.security_policy_uri = "http://opcfoundation.org/UA/SecurityPolicy#None"
        self.security_mode = ua.MessageSecurityMode.None_
        self.secure_channel_id = None
        self.default_timeout = 3600000
        self.secure_channel_timeout = self.default_timeout
        self.session_timeout = self.default_timeout
        self._policy_ids = []
        self.server_certificate = ""
        self.client_certificate = ""
        self.private_key = ""
        self.bclient = BinaryClient(timeout)
        self._nonce = None
        self._session_counter = 1
        self.keepalive = None

    def load_client_certificate(self, path):
        """
        load our certificate from file, either pem or der
        """
        _, ext = os.path.splitext(path)
        with open(path, "br") as f:
            self.client_certificate = f.read()
        if ext == ".pem":
            self.client_certificate = uacrypto.dem_to_der(self.client_certificate)

    def load_private_key(self, path):
        with open(path, "br") as f:
            self.private_key = f.read()

    def connect_and_register_server(self):
        """
        Connect to discovery server, register my server, and disconnect
        """
        self.connect_socket()
        self.send_hello()
        self.open_secure_channel()
        self.register_server()
        self.close_secure_channel()
        self.disconnect_socket()

    def connect_and_get_server_endpoints(self):
        """
        Connect, ask server for endpoints, and disconnect
        """
        self.connect_socket()
        self.send_hello()
        self.open_secure_channel()
        endpoints = self.get_endpoints()
        self.close_secure_channel()
        self.disconnect_socket()
        return endpoints

    def connect_and_find_servers(self):
        """
        Connect, ask server for a list of known servers, and disconnect
        """
        self.connect_socket()
        self.send_hello()
        self.open_secure_channel()  # spec says it should not be necessary to open channel
        servers = self.find_servers()
        self.close_secure_channel()
        self.disconnect_socket()
        return servers

    def connect_and_find_servers_on_network(self):
        """
        Connect, ask server for a list of known servers on network, and disconnect
        """
        self.connect_socket()
        self.send_hello()
        self.open_secure_channel()
        servers = self.find_servers_on_network()
        self.close_secure_channel()
        self.disconnect_socket()
        return servers

    def connect(self):
        """
        High level method
        Connect, create and activate session
        """
        self.connect_socket()
        self.send_hello()
        self.open_secure_channel()
        self.create_session()
        self.activate_session(username=self.server_url.username, password=self.server_url.password, certificate=self.client_certificate)

    def disconnect(self):
        """
        High level method
        Close session, secure channel and socket
        """
        self.close_session()
        self.close_secure_channel()
        self.disconnect_socket()

    def connect_socket(self):
        """
        connect to socket defined in url
        """
        self.bclient.connect_socket(self.server_url.hostname, self.server_url.port)

    def disconnect_socket(self):
        self.bclient.disconnect_socket()

    def send_hello(self):
        """
        Send OPC-UA hello to server
        """
        ack = self.bclient.send_hello(self.server_url.geturl())
        # FIXME check ack

    def open_secure_channel(self, renew=False):
        """
        Open secure channel, if renew is True, renew channel
        """
        params = ua.OpenSecureChannelParameters()
        params.ClientProtocolVersion = 0
        params.RequestType = ua.SecurityTokenRequestType.Issue
        if renew:
            params.RequestType = ua.SecurityTokenRequestType.Renew
        params.SecurityMode = self.security_mode
        params.RequestedLifetime = self.secure_channel_timeout
        params.ClientNonce = '\x00'
        result = self.bclient.open_secure_channel(params)
        self.secure_channel_timeout = result.SecurityToken.RevisedLifetime

    def close_secure_channel(self):
        return self.bclient.close_secure_channel()

    def get_endpoints(self):
        params = ua.GetEndpointsParameters()
        params.EndpointUrl = self.server_url.geturl()
        return self.bclient.get_endpoints(params)

    def register_server(self, server, discovery_configuration=None):
        """
        register a server to discovery server
        if discovery_configuration is provided, the newer register_server2 service call is used
        """
        serv = ua.RegisteredServer()
        serv.ServerUri = server.application_uri
        serv.ProductUri = server.product_uri
        serv.DiscoveryUrls = [server.endpoint.geturl()]
        serv.ServerType = server.application_type
        serv.ServerNames = [ua.LocalizedText(server.name)]
        serv.IsOnline = True
        if discovery_configuration:
            params = ua.registerServer2Parameters()
            params.Server = serv
            params.DiscoveryConfiguration
            return self.bclient.register_server2(params)
        else:
            return self.bclient.register_server(serv)

    def find_servers(self, uris=[]):
        """
        send a FindServer request to the server. The answer should be a list of
        servers the server knows about
        A list of uris can be provided, only server having matching uris will be returned
        """
        params = ua.FindServersParameters()
        params.EndpointUrl = self.server_url.geturl()
        params.ServerUris = uris 
        return self.bclient.find_servers(params)

    def find_servers_on_network(self):
        params = ua.FindServersOnNetworkParameters()
        return self.bclient.find_servers_on_network(params)

    def create_session(self):
        desc = ua.ApplicationDescription()
        desc.ApplicationUri = self.application_uri
        desc.ProductUri = self.product_uri
        desc.ApplicationName = ua.LocalizedText(self.name)
        desc.ApplicationType = ua.ApplicationType.Client

        params = ua.CreateSessionParameters()
        params.ClientNonce = utils.create_nonce()
        params.ClientCertificate = b''
        params.ClientDescription = desc
        params.EndpointUrl = self.server_url.geturl()
        params.SessionName = self.description + " Session" + str(self._session_counter)
        params.RequestedSessionTimeout = 3600000
        params.MaxResponseMessageSize = 0  # means no max size
        params.ClientCertificate = self.client_certificate
        response = self.bclient.create_session(params)
        self.server_certificate = response.ServerCertificate
        for ep in response.ServerEndpoints:
            if urlparse(ep.EndpointUrl).scheme == self.server_url.scheme and ep.SecurityMode == self.security_mode:
                # remember PolicyId's: we will use them in activate_session()
                self._policy_ids = ep.UserIdentityTokens
        self.session_timeout = response.RevisedSessionTimeout
        self.keepalive = KeepAlive(self, min(self.session_timeout, self.secure_channel_timeout) * 0.7)  # 0.7 is from spec
        self.keepalive.start()
        return response

    def server_policy_id(self, token_type, default):
        """
        Find PolicyId of server's UserTokenPolicy by token_type.
        Return default if there's no matching UserTokenPolicy.
        """
        for policy in self._policy_ids:
            if policy.TokenType == token_type:
                return policy.PolicyId
        return default

    def activate_session(self, username=None, password=None, certificate=None):
        """
        Activate session using either username and password or private_key
        """
        params = ua.ActivateSessionParameters()
        params.LocaleIds.append("en")
        if not username and not certificate:
            params.UserIdentityToken = ua.AnonymousIdentityToken()
            params.UserIdentityToken.PolicyId = self.server_policy_id(ua.UserTokenType.Anonymous, b"anonymous")
        elif certificate:
            params.UserIdentityToken = ua.X509IdentityToken()
            params.UserIdentityToken.PolicyId = self.server_policy_id(ua.UserTokenType.Certificate, b"certificate_basic256")
            params.UserIdentityToken.CertificateData = certificate
            sig = uacrypto.sign_sha1(self.private_key, certificate)
            params.UserTokenSignature = ua.SignatureData()
            params.UserTokenSignature.Algorithm = b"http://www.w3.org/2000/09/xmldsig#rsa-sha1"
            params.UserTokenSignature.Signature = sig
        else:
            params.UserIdentityToken = ua.UserNameIdentityToken()
            params.UserIdentityToken.UserName = username 
            if self.server_url.password:
                pubkey = uacrypto.pubkey_from_dercert(self.server_certificate)
                data = uacrypto.encrypt_rsa_oaep(pubkey, bytes(password, "utf8"))
                params.UserIdentityToken.Password = data
            params.UserIdentityToken.PolicyId = self.server_policy_id(ua.UserTokenType.UserName, b"username_basic256")
            params.UserIdentityToken.EncryptionAlgorithm = 'http://www.w3.org/2001/04/xmlenc#rsa-oaep'
        return self.bclient.activate_session(params)

    def close_session(self):
        """
        Close session
        """
        if self.keepalive:
            self.keepalive.stop()
        return self.bclient.close_session(True)

    def get_root_node(self):
        return self.get_node(ua.TwoByteNodeId(ua.ObjectIds.RootFolder))

    def get_objects_node(self):
        return self.get_node(ua.TwoByteNodeId(ua.ObjectIds.ObjectsFolder))

    def get_server_node(self):
        return self.get_node(ua.TwoByteNodeId(ua.ObjectIds.Server))

    def get_node(self, nodeid):
        """
        Get node using NodeId object or a string representing a NodeId
        """
        return Node(self.bclient, nodeid)

    def create_subscription(self, period, handler):
        """
        Create a subscription.
        returns a Subscription object which allow
        to subscribe to events or data on server
        handler argument is a class with data_change and/or event methods.
        These methods will be called when notfication from server are received.
        See example-client.py.
        Do not do expensive/slow or network operation from these methods 
        since they are called directly from receiving thread. This is a design choice,
        start another thread if you need to do such a thing.
        """
        params = ua.CreateSubscriptionParameters()
        params.RequestedPublishingInterval = period
        params.RequestedLifetimeCount = 3000
        params.RequestedMaxKeepAliveCount = 10000
        params.MaxNotificationsPerPublish = 4294967295
        params.PublishingEnabled = True
        params.Priority = 0
        return Subscription(self.bclient, params, handler)

    def get_namespace_array(self):
        ns_node = self.get_node(ua.NodeId(ua.ObjectIds.Server_NamespaceArray))
        return ns_node.get_value()

    def get_namespace_index(self, uri):
        uries = self.get_namespace_array()
        return uries.index(uri)


1	1	from __future__ import division # support for python2
2	1	import os
3	1	from threading import Thread, Condition
4	1	import logging
5	1	try:
6	1	from urllib.parse import urlparse
7		except ImportError: # support for python2
8		from urlparse import urlparse
9
10	1	from opcua import uaprotocol as ua
11	1	from opcua import BinaryClient, Node, Subscription
12	1	from opcua import utils
13	1	from opcua import uacrypto
14
15
16	1	class KeepAlive(Thread):
17
18		"""
19		Used by Client to keep session opened.
20		OPCUA defines timeout both for sessions and secure channel
21		"""
22
23	1	def __init__(self, client, timeout):
24	1	Thread.__init__(self)
25	1	self.logger = logging.getLogger(__name__)
26	1	if timeout == 0: # means no timeout bu we do not trust such servers
27		timeout = 360000
28	1	self.timeout = timeout
29	1	self.client = client
30	1	self._dostop = False
31	1	self._cond = Condition()
32
33	1	def run(self):
34	1	self.logger.debug("starting keepalive thread with period of %s milliseconds", self.timeout)
35	1	server_state = self.client.get_node(ua.FourByteNodeId(ua.ObjectIds.Server_ServerStatus_State))
36	1	while not self._dostop:
37	1	with self._cond:
38	1	self._cond.wait(self.timeout / 1000)
39	1	if self._dostop:
40	1	break
41		self.logger.debug("renewing channel")
42		self.client.open_secure_channel(renew=True)
43		val = server_state.get_value()
44		self.logger.debug("server state is: %s ", val)
45	1	self.logger.debug("keepalive thread has stopped")
46
47	1	def stop(self):
48	1	self.logger.debug("stoping keepalive thread")
49	1	with self._cond:
50	1	self._cond.notify_all()
51	1	self._dostop = True
52
53
54	1	class Client(object):
55
56		"""
57		High level client to connect to an OPC-UA server.
58		This class makes it easy to connect and browse address space.
59		It attemps to expose as much functionality as possible
60		but if you want to do to special things you will probably need
61		to work with the BinaryClient object, available as self.bclient
62		which offers a raw OPC-UA interface.
63		"""
64
65	1	def __init__(self, url, timeout=1):
66		"""
67		used url argument to connect to server.
68		if you are unsure of url, write at least hostname and port
69		and call get_endpoints
70		timeout is the timeout to get an answer for requests to server
71		public member of this call are available to be set by API users
72
73		"""
74	1	self.logger = logging.getLogger(__name__)
75	1	self.server_url = urlparse(url)
76	1	self.name = "Pure Python Client"
77	1	self.description = self.name
78	1	self.application_uri = "urn:freeopcua:client"
79	1	self.product_uri = "urn:freeopcua.github.no:client"
80	1	self.security_policy_uri = "http://opcfoundation.org/UA/SecurityPolicy#None"
81	1	self.security_mode = ua.MessageSecurityMode.None_
82	1	self.secure_channel_id = None
83	1	self.default_timeout = 3600000
84	1	self.secure_channel_timeout = self.default_timeout
85	1	self.session_timeout = self.default_timeout
86	1	self._policy_ids = []
87	1	self.server_certificate = ""
88	1	self.client_certificate = ""
89	1	self.private_key = ""
90	1	self.bclient = BinaryClient(timeout)
91	1	self._nonce = None
92	1	self._session_counter = 1
93	1	self.keepalive = None
94
95	1	def load_client_certificate(self, path):
96		"""
97		load our certificate from file, either pem or der
98		"""
99		_, ext = os.path.splitext(path)
100		with open(path, "br") as f:
101		self.client_certificate = f.read()
102		if ext == ".pem":
103		self.client_certificate = uacrypto.dem_to_der(self.client_certificate)
104
105	1	def load_private_key(self, path):
106		with open(path, "br") as f:
107		self.private_key = f.read()
108
109	1	def connect_and_register_server(self):
110		"""
111		Connect to discovery server, register my server, and disconnect
112		"""
113		self.connect_socket()
114		self.send_hello()
115		self.open_secure_channel()
116		self.register_server()
117		self.close_secure_channel()
118		self.disconnect_socket()
119
120	1	def connect_and_get_server_endpoints(self):
121		"""
122		Connect, ask server for endpoints, and disconnect
123		"""
124		self.connect_socket()
125		self.send_hello()
126		self.open_secure_channel()
127		endpoints = self.get_endpoints()
128		self.close_secure_channel()
129		self.disconnect_socket()
130		return endpoints
131
132	1	def connect_and_find_servers(self):
133		"""
134		Connect, ask server for a list of known servers, and disconnect
135		"""
136		self.connect_socket()
137		self.send_hello()
138		self.open_secure_channel() # spec says it should not be necessary to open channel
139		servers = self.find_servers()
140		self.close_secure_channel()
141		self.disconnect_socket()
142		return servers
143
144	1	def connect_and_find_servers_on_network(self):
145		"""
146		Connect, ask server for a list of known servers on network, and disconnect
147		"""
148		self.connect_socket()
149		self.send_hello()
150		self.open_secure_channel()
151		servers = self.find_servers_on_network()
152		self.close_secure_channel()
153		self.disconnect_socket()
154		return servers
155
156	1	def connect(self):
157		"""
158		High level method
159		Connect, create and activate session
160		"""
161	1	self.connect_socket()
162	1	self.send_hello()
163	1	self.open_secure_channel()
164	1	self.create_session()
165	1	self.activate_session(username=self.server_url.username, password=self.server_url.password, certificate=self.client_certificate)
166
167	1	def disconnect(self):
168		"""
169		High level method
170		Close session, secure channel and socket
171		"""
172	1	self.close_session()
173	1	self.close_secure_channel()
174	1	self.disconnect_socket()
175
176	1	def connect_socket(self):
177		"""
178		connect to socket defined in url
179		"""
180	1	self.bclient.connect_socket(self.server_url.hostname, self.server_url.port)
181
182	1	def disconnect_socket(self):
183	1	self.bclient.disconnect_socket()
184
185	1	def send_hello(self):
186		"""
187		Send OPC-UA hello to server
188		"""
189	1	ack = self.bclient.send_hello(self.server_url.geturl())
190		# FIXME check ack
191
192	1	def open_secure_channel(self, renew=False):
193		"""
194		Open secure channel, if renew is True, renew channel
195		"""
196	1	params = ua.OpenSecureChannelParameters()
197	1	params.ClientProtocolVersion = 0
198	1	params.RequestType = ua.SecurityTokenRequestType.Issue
199	1	if renew:
200		params.RequestType = ua.SecurityTokenRequestType.Renew
201	1	params.SecurityMode = self.security_mode
202	1	params.RequestedLifetime = self.secure_channel_timeout
203	1	params.ClientNonce = '\x00'
204	1	result = self.bclient.open_secure_channel(params)
205	1	self.secure_channel_timeout = result.SecurityToken.RevisedLifetime
206
207	1	def close_secure_channel(self):
208	1	return self.bclient.close_secure_channel()
209
210	1	def get_endpoints(self):
211	1	params = ua.GetEndpointsParameters()
212	1	params.EndpointUrl = self.server_url.geturl()
213	1	return self.bclient.get_endpoints(params)
214
215	1	def register_server(self, server, discovery_configuration=None):
216		"""
217		register a server to discovery server
218		if discovery_configuration is provided, the newer register_server2 service call is used
219		"""
220	1	serv = ua.RegisteredServer()
221	1	serv.ServerUri = server.application_uri
222	1	serv.ProductUri = server.product_uri
223	1	serv.DiscoveryUrls = [server.endpoint.geturl()]
224	1	serv.ServerType = server.application_type
225	1	serv.ServerNames = [ua.LocalizedText(server.name)]
226	1	serv.IsOnline = True
227	1	if discovery_configuration:
228		params = ua.registerServer2Parameters()
229		params.Server = serv
230		params.DiscoveryConfiguration
231		return self.bclient.register_server2(params)
232		else:
233	1	return self.bclient.register_server(serv)
234
235	1	def find_servers(self, uris=[]):
236		"""
237		send a FindServer request to the server. The answer should be a list of
238		servers the server knows about
239		A list of uris can be provided, only server having matching uris will be returned
240		"""
241	1	params = ua.FindServersParameters()
242	1	params.EndpointUrl = self.server_url.geturl()
243	1	params.ServerUris = uris
244	1	return self.bclient.find_servers(params)
245
246	1	def find_servers_on_network(self):
247		params = ua.FindServersOnNetworkParameters()
248		return self.bclient.find_servers_on_network(params)
249
250	1	def create_session(self):
251	1	desc = ua.ApplicationDescription()
252	1	desc.ApplicationUri = self.application_uri
253	1	desc.ProductUri = self.product_uri
254	1	desc.ApplicationName = ua.LocalizedText(self.name)
255	1	desc.ApplicationType = ua.ApplicationType.Client
256
257	1	params = ua.CreateSessionParameters()
258	1	params.ClientNonce = utils.create_nonce()
259	1	params.ClientCertificate = b''
260	1	params.ClientDescription = desc
261	1	params.EndpointUrl = self.server_url.geturl()
262	1	params.SessionName = self.description + " Session" + str(self._session_counter)
263	1	params.RequestedSessionTimeout = 3600000
264	1	params.MaxResponseMessageSize = 0 # means no max size
265	1	params.ClientCertificate = self.client_certificate
266	1	response = self.bclient.create_session(params)
267	1	self.server_certificate = response.ServerCertificate
268	1	for ep in response.ServerEndpoints:
269	1	if urlparse(ep.EndpointUrl).scheme == self.server_url.scheme and ep.SecurityMode == self.security_mode:
270		# remember PolicyId's: we will use them in activate_session()
271	1	self._policy_ids = ep.UserIdentityTokens
272	1	self.session_timeout = response.RevisedSessionTimeout
273	1	self.keepalive = KeepAlive(self, min(self.session_timeout, self.secure_channel_timeout) * 0.7) # 0.7 is from spec
274	1	self.keepalive.start()
275	1	return response
276
277	1	def server_policy_id(self, token_type, default):
278		"""
279		Find PolicyId of server's UserTokenPolicy by token_type.
280		Return default if there's no matching UserTokenPolicy.
281		"""
282	1	for policy in self._policy_ids:
283	1	if policy.TokenType == token_type:
284	1	return policy.PolicyId
285	1	return default
286
287	1	def activate_session(self, username=None, password=None, certificate=None):
288		"""
289		Activate session using either username and password or private_key
290		"""
291	1	params = ua.ActivateSessionParameters()
292	1	params.LocaleIds.append("en")
293	1	if not username and not certificate:
294	1	params.UserIdentityToken = ua.AnonymousIdentityToken()
295	1	params.UserIdentityToken.PolicyId = self.server_policy_id(ua.UserTokenType.Anonymous, b"anonymous")
296	1	elif certificate:
297		params.UserIdentityToken = ua.X509IdentityToken()
298		params.UserIdentityToken.PolicyId = self.server_policy_id(ua.UserTokenType.Certificate, b"certificate_basic256")
299		params.UserIdentityToken.CertificateData = certificate
300		sig = uacrypto.sign_sha1(self.private_key, certificate)
301		params.UserTokenSignature = ua.SignatureData()
302		params.UserTokenSignature.Algorithm = b"http://www.w3.org/2000/09/xmldsig#rsa-sha1"
303		params.UserTokenSignature.Signature = sig
304		else:
305	1	params.UserIdentityToken = ua.UserNameIdentityToken()
306	1	params.UserIdentityToken.UserName = username
307	1	if self.server_url.password:
308		pubkey = uacrypto.pubkey_from_dercert(self.server_certificate)
309		data = uacrypto.encrypt_rsa_oaep(pubkey, bytes(password, "utf8"))
310		params.UserIdentityToken.Password = data
311	1	params.UserIdentityToken.PolicyId = self.server_policy_id(ua.UserTokenType.UserName, b"username_basic256")
312	1	params.UserIdentityToken.EncryptionAlgorithm = 'http://www.w3.org/2001/04/xmlenc#rsa-oaep'
313	1	return self.bclient.activate_session(params)
314
315	1	def close_session(self):
316		"""
317		Close session
318		"""
319	1	if self.keepalive:
320	1	self.keepalive.stop()
321	1	return self.bclient.close_session(True)
322
323	1	def get_root_node(self):
324	1	return self.get_node(ua.TwoByteNodeId(ua.ObjectIds.RootFolder))
325
326	1	def get_objects_node(self):
327	1	return self.get_node(ua.TwoByteNodeId(ua.ObjectIds.ObjectsFolder))
328
329	1	def get_server_node(self):
330	1	return self.get_node(ua.TwoByteNodeId(ua.ObjectIds.Server))
331
332	1	def get_node(self, nodeid):
333		"""
334		Get node using NodeId object or a string representing a NodeId
335		"""
336	1	return Node(self.bclient, nodeid)
337
338	1	def create_subscription(self, period, handler):
339		"""
340		Create a subscription.
341		returns a Subscription object which allow
342		to subscribe to events or data on server
343		handler argument is a class with data_change and/or event methods.
344		These methods will be called when notfication from server are received.
345		See example-client.py.
346		Do not do expensive/slow or network operation from these methods
347		since they are called directly from receiving thread. This is a design choice,
348		start another thread if you need to do such a thing.
349		"""
350	1	params = ua.CreateSubscriptionParameters()
351	1	params.RequestedPublishingInterval = period
352	1	params.RequestedLifetimeCount = 3000
353	1	params.RequestedMaxKeepAliveCount = 10000
354	1	params.MaxNotificationsPerPublish = 4294967295
355	1	params.PublishingEnabled = True
356	1	params.Priority = 0
357	1	return Subscription(self.bclient, params, handler)
358
359	1	def get_namespace_array(self):
360	1	ns_node = self.get_node(ua.NodeId(ua.ObjectIds.Server_NamespaceArray))
361	1	return ns_node.get_value()
362
363	1	def get_namespace_index(self, uri):
364	1	uries = self.get_namespace_array()
365		return uries.index(uri)
366

FreeOpcUa / python-opcua

Pull Request — master (#70)

opcua.Client.get_server_node() A

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