Client.import_xml() - Code Metrics - Inspection of "allow to import and export xml client side" - FreeOpcUa/python-opcua - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Push — master ( 4eddf2...83c23e )

by Olivier

created 2016-12-30 10:07 UTC

Client.import_xml() A

↳ Parent: Project

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Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	3
CRAP Score	1

Importance

Changes	1
Bugs	0	Features	0

Metric	Value
cc	1
c	1
b	0
f	0
dl	0
loc	6
ccs	3
cts	3
cp	1
crap	1
rs	9.4285

from __future__ import division  # support for python2
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 ua
from opcua.client.ua_client import UaClient
from opcua.common.xmlimporter import XmlImporter
from opcua.common.xmlexporter import XmlExporter
from opcua.common.node import Node
from opcua.common.manage_nodes import delete_nodes
from opcua.common.subscription import Subscription
from opcua.common import utils
from opcua.crypto import security_policies
from opcua.common.shortcuts import Shortcuts
use_crypto = True
try:
    from opcua.crypto import uacrypto
except ImportError:
    print("cryptography is not installed, use of crypto disabled")
    use_crypto = False


class KeepAlive(Thread):

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

    def __init__(self, client, timeout):
        """
        :param session_timeout: Timeout to re-new the session
            in milliseconds.
        """
        Thread.__init__(self)
        self.logger = logging.getLogger(__name__)

        self.client = client
        self._dostop = False
        self._cond = Condition()
        self.timeout = timeout

        # some server support no timeout, but we do not trust them
        if self.timeout == 0:
            self.timeout = 3600000 # 1 hour

    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")
        self._dostop = True
        with self._cond:
            self._cond.notify_all()


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 more flexibility it is possible and adviced to
    use UaClient object, available as self.uaclient
    which offers the raw OPC-UA services interface.
    """

    def __init__(self, url, timeout=4):
        """

        :param url: url of the server.
            if you are unsure of url, write at least hostname
            and port and call get_endpoints

        :param timeout:
            Each request sent to the server expects an answer within this
            time. The timeout is specified in seconds.
        """
        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 = ua.SecurityPolicy()
        self.secure_channel_id = None
        self.secure_channel_timeout = 3600000 # 1 hour
        self.session_timeout = 3600000 # 1 hour
        self._policy_ids = []
        self.uaclient = UaClient(timeout)
        self.user_certificate = None
        self.user_private_key = None
        self._session_counter = 1
        self.keepalive = None
        self.nodes = Shortcuts(self.uaclient)

    def __enter__(self):
        self.connect()
        return self

    def __exit__(self, exc_type, exc_value, traceback):
        self.disconnect()

    @staticmethod
    def find_endpoint(endpoints, security_mode, policy_uri):
        """
        Find endpoint with required security mode and policy URI
        """
        for ep in endpoints:
            if (ep.EndpointUrl.startswith(ua.OPC_TCP_SCHEME) and
                    ep.SecurityMode == security_mode and
                    ep.SecurityPolicyUri == policy_uri):
                return ep
        raise ua.UaError("No matching endpoints: {0}, {1}".format(
                         security_mode, policy_uri))

    def set_security_string(self, string):
        """
        Set SecureConnection mode. String format:
        Policy,Mode,certificate,private_key[,server_private_key]
        where Policy is Basic128Rsa15 or Basic256,
            Mode is Sign or SignAndEncrypt
            certificate, private_key and server_private_key are
                paths to .pem or .der files
        Call this before connect()
        """
        if not string:
            return
        parts = string.split(',')
        if len(parts) < 4:
            raise ua.UaError('Wrong format: `{0}`, expected at least 4 comma-separated values'.format(string))
        policy_class = getattr(security_policies, 'SecurityPolicy' + parts[0])
        mode = getattr(ua.MessageSecurityMode, parts[1])
        return self.set_security(policy_class, parts[2], parts[3],
                                 parts[4] if len(parts) >= 5 else None, mode)

    def set_security(self, policy, certificate_path, private_key_path,
                     server_certificate_path=None,
                     mode=ua.MessageSecurityMode.SignAndEncrypt):
        """
        Set SecureConnection mode.
        Call this before connect()
        """
        if server_certificate_path is None:
            # load certificate from server's list of endpoints
            endpoints = self.connect_and_get_server_endpoints()
            endpoint = Client.find_endpoint(endpoints, mode, policy.URI)
            server_cert = uacrypto.x509_from_der(endpoint.ServerCertificate)
        else:
            server_cert = uacrypto.load_certificate(server_certificate_path)
        cert = uacrypto.load_certificate(certificate_path)
        pk = uacrypto.load_private_key(private_key_path)
        self.security_policy = policy(server_cert, cert, pk, mode)
        self.uaclient.set_security(self.security_policy)

    def load_client_certificate(self, path):
        """
        load our certificate from file, either pem or der
        """
        self.user_certificate = uacrypto.load_certificate(path)

    def load_private_key(self, path):
        """
        Load user private key. This is used for authenticating using certificate
        """
        self.user_private_key = uacrypto.load_private_key(path)

    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.user_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.uaclient.connect_socket(self.server_url.hostname, self.server_url.port)

    def disconnect_socket(self):
        self.uaclient.disconnect_socket()

    def send_hello(self):
        """
        Send OPC-UA hello to server
        """
        ack = self.uaclient.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_policy.Mode
        params.RequestedLifetime = self.secure_channel_timeout
        nonce = utils.create_nonce(self.security_policy.symmetric_key_size)   # length should be equal to the length of key of symmetric encryption
        params.ClientNonce = nonce	# this nonce is used to create a symmetric key
        result = self.uaclient.open_secure_channel(params)
        self.security_policy.make_symmetric_key(nonce, result.ServerNonce)
        self.secure_channel_timeout = result.SecurityToken.RevisedLifetime

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

    def get_endpoints(self):
        params = ua.GetEndpointsParameters()
        params.EndpointUrl = self.server_url.geturl()
        return self.uaclient.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 = discovery_configuration
            return self.uaclient.register_server2(params)
        else:
            return self.uaclient.register_server(serv)

    def find_servers(self, uris=None):
        """
        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
        """
        if uris is None:
            uris = []
        params = ua.FindServersParameters()
        params.EndpointUrl = self.server_url.geturl()
        params.ServerUris = uris
        return self.uaclient.find_servers(params)

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

    def create_session(self):
        """
        send a CreateSessionRequest to server with reasonable parameters.
        If you want o modify settings look at code of this methods
        and make your own
        """
        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()
        nonce = utils.create_nonce(32)  # at least 32 random bytes for server to prove possession of private key (specs part 4, 5.6.2.2)
        params.ClientNonce = nonce
        params.ClientCertificate = self.security_policy.client_certificate
        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
        response = self.uaclient.create_session(params)
        if self.security_policy.client_certificate is None:
            data = nonce
        else:
            data = self.security_policy.client_certificate + nonce
        self.security_policy.asymmetric_cryptography.verify(data, response.ServerSignature.Signature)
        self._server_nonce = response.ServerNonce
        if not self.security_policy.server_certificate:
            self.security_policy.server_certificate = response.ServerCertificate
        elif self.security_policy.server_certificate != response.ServerCertificate:
            raise ua.UaError("Server certificate mismatch")
        # remember PolicyId's: we will use them in activate_session()
        ep = Client.find_endpoint(response.ServerEndpoints, self.security_policy.Mode, self.security_policy.URI)
        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 server_policy_uri(self, token_type):
        """
        Find SecurityPolicyUri of server's UserTokenPolicy by token_type.
        If SecurityPolicyUri is empty, use default SecurityPolicyUri
        of the endpoint
        """
        for policy in self._policy_ids:
            if policy.TokenType == token_type:
                if policy.SecurityPolicyUri:
                    return policy.SecurityPolicyUri
                else:   # empty URI means "use this endpoint's policy URI"
                    return self.security_policy.URI
        return self.security_policy.URI

    def activate_session(self, username=None, password=None, certificate=None):
        """
        Activate session using either username and password or private_key
        """
        params = ua.ActivateSessionParameters()
        challenge = b""
        if self.security_policy.server_certificate is not None:
            challenge += self.security_policy.server_certificate
        if self._server_nonce is not None:
            challenge += self._server_nonce
        params.ClientSignature.Algorithm = b"http://www.w3.org/2000/09/xmldsig#rsa-sha1"
        params.ClientSignature.Signature = self.security_policy.asymmetric_cryptography.signature(challenge)
        params.LocaleIds.append("en")
        if not username and not certificate:
            self._add_anonymous_auth(params)
        elif certificate:
            self._add_certificate_auth(params, certificate, challenge)
        else:
            self._add_user_auth(params, username, password)
        return self.uaclient.activate_session(params)

    def _add_anonymous_auth(self, params):
        params.UserIdentityToken = ua.AnonymousIdentityToken()
        params.UserIdentityToken.PolicyId = self.server_policy_id(ua.UserTokenType.Anonymous, b"anonymous")

    def _add_certificate_auth(self, params, certificate, challenge):
        params.UserIdentityToken = ua.X509IdentityToken()
        params.UserIdentityToken.PolicyId = self.server_policy_id(ua.UserTokenType.Certificate, b"certificate_basic256")
        params.UserIdentityToken.CertificateData = uacrypto.der_from_x509(certificate)
        # specs part 4, 5.6.3.1: the data to sign is created by appending
        # the last serverNonce to the serverCertificate
        sig = uacrypto.sign_sha1(self.user_private_key, challenge)
        params.UserTokenSignature = ua.SignatureData()
        params.UserTokenSignature.Algorithm = b"http://www.w3.org/2000/09/xmldsig#rsa-sha1"
        params.UserTokenSignature.Signature = sig

    def _add_user_auth(self, params, username, password):
        params.UserIdentityToken = ua.UserNameIdentityToken()
        params.UserIdentityToken.UserName = username
        policy_uri = self.server_policy_uri(ua.UserTokenType.UserName)
        if not policy_uri or policy_uri == security_policies.POLICY_NONE_URI:
            # see specs part 4, 7.36.3: if the token is NOT encrypted,
            # then the password only contains UTF-8 encoded password
            # and EncryptionAlgorithm is null
            if self.server_url.password:
                self.logger.warning("Sending plain-text password")
                params.UserIdentityToken.Password = password
            params.UserIdentityToken.EncryptionAlgorithm = ''
        elif self.server_url.password:
            data, uri = self._encrypt_password(password, policy_uri)
            params.UserIdentityToken.Password = data 
            params.UserIdentityToken.EncryptionAlgorithm = uri
        params.UserIdentityToken.PolicyId = self.server_policy_id(ua.UserTokenType.UserName, b"username_basic256")

    def _encrypt_password(self, password, policy_uri):
        pubkey = uacrypto.x509_from_der(self.security_policy.server_certificate).public_key()
        # see specs part 4, 7.36.3: if the token is encrypted, password
        # shall be converted to UTF-8 and serialized with server nonce
        passwd = password.encode("utf8")
        if self._server_nonce is not None:
            passwd += self._server_nonce
        etoken = ua.ua_binary.Primitives.Bytes.pack(passwd)
        data, uri = security_policies.encrypt_asymmetric(pubkey, etoken, policy_uri)
        return data, uri

    def close_session(self):
        """
        Close session
        """
        if self.keepalive:
            self.keepalive.stop()
        return self.uaclient.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.FourByteNodeId(ua.ObjectIds.Server))

    def get_node(self, nodeid):
        """
        Get node using NodeId object or a string representing a NodeId
        """
        return Node(self.uaclient, 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.
        period argument is either a publishing interval in seconds or a 
        CreateSubscriptionParameters instance. The second option should be used,
        if the opcua-server has problems with the default options.
        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.  
        """
        
        if isinstance(period, ua.CreateSubscriptionParameters):
             return Subscription(self.uaclient, period, handler)
        params = ua.CreateSubscriptionParameters()
        params.RequestedPublishingInterval = period
        params.RequestedLifetimeCount = 10000
        params.RequestedMaxKeepAliveCount = 3000
        params.MaxNotificationsPerPublish = 10000
        params.PublishingEnabled = True
        params.Priority = 0
        return Subscription(self.uaclient, 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)

    def delete_nodes(self, nodes, recursive=False):
        return delete_nodes(self.uaclient, nodes, recursive)

    def import_xml(self, path):
        """
        Import nodes defined in xml
        """
        importer = XmlImporter(self)
        return importer.import_xml(path)

    def export_xml(self, nodes, path):
        """
        Export defined nodes to xml
        """
        exp = XmlExporter(self)
        exp.build_etree(nodes)
        return exp.write_xml(path)

    def register_namespace(self, uri):
        """
        Register a new namespace. Nodes should in custom namespace, not 0.
        This method is mainly implemented for symetry with server
        """
        ns_node = self.get_node(ua.NodeId(ua.ObjectIds.Server_NamespaceArray))
        uries = ns_node.get_value()
        if uri in uries:
            return uries.index(uri)
        uries.append(uri)
        ns_node.set_value(uries)
        return len(uries) - 1




1	1	from __future__ import division # support for python2
2	1	from threading import Thread, Condition
3	1	import logging
4	1	try:
5	1	from urllib.parse import urlparse
6		except ImportError: # support for python2
7		from urlparse import urlparse
8
9	1	from opcua import ua
10	1	from opcua.client.ua_client import UaClient
11	1	from opcua.common.xmlimporter import XmlImporter
12	1	from opcua.common.xmlexporter import XmlExporter
13	1	from opcua.common.node import Node
14	1	from opcua.common.manage_nodes import delete_nodes
15	1	from opcua.common.subscription import Subscription
16	1	from opcua.common import utils
17	1	from opcua.crypto import security_policies
18	1	from opcua.common.shortcuts import Shortcuts
19	1	use_crypto = True
20	1	try:
21	1	from opcua.crypto import uacrypto
22		except ImportError:
23		print("cryptography is not installed, use of crypto disabled")
24		use_crypto = False
25
26
27	1	class KeepAlive(Thread):
28
29		"""
30		Used by Client to keep the session open.
31		OPCUA defines timeout both for sessions and secure channel
32		"""
33
34	1	def __init__(self, client, timeout):
35		"""
36		:param session_timeout: Timeout to re-new the session
37		in milliseconds.
38		"""
39	1	Thread.__init__(self)
40	1	self.logger = logging.getLogger(__name__)
41
42	1	self.client = client
43	1	self._dostop = False
44	1	self._cond = Condition()
45	1	self.timeout = timeout
46
47		# some server support no timeout, but we do not trust them
48	1	if self.timeout == 0:
49		self.timeout = 3600000 # 1 hour
50
51	1	def run(self):
52	1	self.logger.debug("starting keepalive thread with period of %s milliseconds", self.timeout)
53	1	server_state = self.client.get_node(ua.FourByteNodeId(ua.ObjectIds.Server_ServerStatus_State))
54	1	while not self._dostop:
55	1	with self._cond:
56	1	self._cond.wait(self.timeout / 1000)
57	1	if self._dostop:
58	1	break
59		self.logger.debug("renewing channel")
60		self.client.open_secure_channel(renew=True)
61		val = server_state.get_value()
62		self.logger.debug("server state is: %s ", val)
63	1	self.logger.debug("keepalive thread has stopped")
64
65	1	def stop(self):
66	1	self.logger.debug("stoping keepalive thread")
67	1	self._dostop = True
68	1	with self._cond:
69	1	self._cond.notify_all()
70
71
72	1	class Client(object):
73
74		"""
75		High level client to connect to an OPC-UA server.
76
77		This class makes it easy to connect and browse address space.
78		It attemps to expose as much functionality as possible
79		but if you want more flexibility it is possible and adviced to
80		use UaClient object, available as self.uaclient
81		which offers the raw OPC-UA services interface.
82		"""
83
84	1	def __init__(self, url, timeout=4):
85		"""
86
87		:param url: url of the server.
88		if you are unsure of url, write at least hostname
89		and port and call get_endpoints
90
91		:param timeout:
92		Each request sent to the server expects an answer within this
93		time. The timeout is specified in seconds.
94		"""
95	1	self.logger = logging.getLogger(__name__)
96	1	self.server_url = urlparse(url)
97	1	self.name = "Pure Python Client"
98	1	self.description = self.name
99	1	self.application_uri = "urn:freeopcua:client"
100	1	self.product_uri = "urn:freeopcua.github.no:client"
101	1	self.security_policy = ua.SecurityPolicy()
102	1	self.secure_channel_id = None
103	1	self.secure_channel_timeout = 3600000 # 1 hour
104	1	self.session_timeout = 3600000 # 1 hour
105	1	self._policy_ids = []
106	1	self.uaclient = UaClient(timeout)
107	1	self.user_certificate = None
108	1	self.user_private_key = None
109	1	self._session_counter = 1
110	1	self.keepalive = None
111	1	self.nodes = Shortcuts(self.uaclient)
112
113	1	def __enter__(self):
114	1	self.connect()
115	1	return self
116
117	1	def __exit__(self, exc_type, exc_value, traceback):
118	1	self.disconnect()
119
120	1	@staticmethod
121		def find_endpoint(endpoints, security_mode, policy_uri):
122		"""
123		Find endpoint with required security mode and policy URI
124		"""
125	1	for ep in endpoints:
126	1	if (ep.EndpointUrl.startswith(ua.OPC_TCP_SCHEME) and
127		ep.SecurityMode == security_mode and
128		ep.SecurityPolicyUri == policy_uri):
129	1	return ep
130	1	raise ua.UaError("No matching endpoints: {0}, {1}".format(
131		security_mode, policy_uri))
132
133	1	def set_security_string(self, string):
134		"""
135		Set SecureConnection mode. String format:
136		Policy,Mode,certificate,private_key[,server_private_key]
137		where Policy is Basic128Rsa15 or Basic256,
138		Mode is Sign or SignAndEncrypt
139		certificate, private_key and server_private_key are
140		paths to .pem or .der files
141		Call this before connect()
142		"""
143	1	if not string:
144		return
145	1	parts = string.split(',')
146	1	if len(parts) < 4:
147		raise ua.UaError('Wrong format: `{0}`, expected at least 4 comma-separated values'.format(string))
148	1	policy_class = getattr(security_policies, 'SecurityPolicy' + parts[0])
149	1	mode = getattr(ua.MessageSecurityMode, parts[1])
150	1	return self.set_security(policy_class, parts[2], parts[3],
151		parts[4] if len(parts) >= 5 else None, mode)
152
153	1	def set_security(self, policy, certificate_path, private_key_path,
154		server_certificate_path=None,
155		mode=ua.MessageSecurityMode.SignAndEncrypt):
156		"""
157		Set SecureConnection mode.
158		Call this before connect()
159		"""
160	1	if server_certificate_path is None:
161		# load certificate from server's list of endpoints
162	1	endpoints = self.connect_and_get_server_endpoints()
163	1	endpoint = Client.find_endpoint(endpoints, mode, policy.URI)
164	1	server_cert = uacrypto.x509_from_der(endpoint.ServerCertificate)
165		else:
166		server_cert = uacrypto.load_certificate(server_certificate_path)
167	1	cert = uacrypto.load_certificate(certificate_path)
168	1	pk = uacrypto.load_private_key(private_key_path)
169	1	self.security_policy = policy(server_cert, cert, pk, mode)
170	1	self.uaclient.set_security(self.security_policy)
171
172	1	def load_client_certificate(self, path):
173		"""
174		load our certificate from file, either pem or der
175		"""
176		self.user_certificate = uacrypto.load_certificate(path)
177
178	1	def load_private_key(self, path):
179		"""
180		Load user private key. This is used for authenticating using certificate
181		"""
182		self.user_private_key = uacrypto.load_private_key(path)
183
184	1	def connect_and_get_server_endpoints(self):
185		"""
186		Connect, ask server for endpoints, and disconnect
187		"""
188	1	self.connect_socket()
189	1	self.send_hello()
190	1	self.open_secure_channel()
191	1	endpoints = self.get_endpoints()
192	1	self.close_secure_channel()
193	1	self.disconnect_socket()
194	1	return endpoints
195
196	1	def connect_and_find_servers(self):
197		"""
198		Connect, ask server for a list of known servers, and disconnect
199		"""
200		self.connect_socket()
201		self.send_hello()
202		self.open_secure_channel() # spec says it should not be necessary to open channel
203		servers = self.find_servers()
204		self.close_secure_channel()
205		self.disconnect_socket()
206		return servers
207
208	1	def connect_and_find_servers_on_network(self):
209		"""
210		Connect, ask server for a list of known servers on network, and disconnect
211		"""
212		self.connect_socket()
213		self.send_hello()
214		self.open_secure_channel()
215		servers = self.find_servers_on_network()
216		self.close_secure_channel()
217		self.disconnect_socket()
218		return servers
219
220	1	def connect(self):
221		"""
222		High level method
223		Connect, create and activate session
224		"""
225	1	self.connect_socket()
226	1	self.send_hello()
227	1	self.open_secure_channel()
228	1	self.create_session()
229	1	self.activate_session(username=self.server_url.username, password=self.server_url.password, certificate=self.user_certificate)
230
231	1	def disconnect(self):
232		"""
233		High level method
234		Close session, secure channel and socket
235		"""
236	1	self.close_session()
237	1	self.close_secure_channel()
238	1	self.disconnect_socket()
239
240	1	def connect_socket(self):
241		"""
242		connect to socket defined in url
243		"""
244	1	self.uaclient.connect_socket(self.server_url.hostname, self.server_url.port)
245
246	1	def disconnect_socket(self):
247	1	self.uaclient.disconnect_socket()
248
249	1	def send_hello(self):
250		"""
251		Send OPC-UA hello to server
252		"""
253	1	ack = self.uaclient.send_hello(self.server_url.geturl())
254		# FIXME check ack
255
256	1	def open_secure_channel(self, renew=False):
257		"""
258		Open secure channel, if renew is True, renew channel
259		"""
260	1	params = ua.OpenSecureChannelParameters()
261	1	params.ClientProtocolVersion = 0
262	1	params.RequestType = ua.SecurityTokenRequestType.Issue
263	1	if renew:
264		params.RequestType = ua.SecurityTokenRequestType.Renew
265	1	params.SecurityMode = self.security_policy.Mode
266	1	params.RequestedLifetime = self.secure_channel_timeout
267	1	nonce = utils.create_nonce(self.security_policy.symmetric_key_size) # length should be equal to the length of key of symmetric encryption
268	1	params.ClientNonce = nonce # this nonce is used to create a symmetric key
269	1	result = self.uaclient.open_secure_channel(params)
270	1	self.security_policy.make_symmetric_key(nonce, result.ServerNonce)
271	1	self.secure_channel_timeout = result.SecurityToken.RevisedLifetime
272
273	1	def close_secure_channel(self):
274	1	return self.uaclient.close_secure_channel()
275
276	1	def get_endpoints(self):
277	1	params = ua.GetEndpointsParameters()
278	1	params.EndpointUrl = self.server_url.geturl()
279	1	return self.uaclient.get_endpoints(params)
280
281	1	def register_server(self, server, discovery_configuration=None):
282		"""
283		register a server to discovery server
284		if discovery_configuration is provided, the newer register_server2 service call is used
285		"""
286	1	serv = ua.RegisteredServer()
287	1	serv.ServerUri = server.application_uri
288	1	serv.ProductUri = server.product_uri
289	1	serv.DiscoveryUrls = [server.endpoint.geturl()]
290	1	serv.ServerType = server.application_type
291	1	serv.ServerNames = [ua.LocalizedText(server.name)]
292	1	serv.IsOnline = True
293	1	if discovery_configuration:
294		params = ua.RegisterServer2Parameters()
295		params.Server = serv
296		params.DiscoveryConfiguration = discovery_configuration
297		return self.uaclient.register_server2(params)
298		else:
299	1	return self.uaclient.register_server(serv)
300
301	1	def find_servers(self, uris=None):
302		"""
303		send a FindServer request to the server. The answer should be a list of
304		servers the server knows about
305		A list of uris can be provided, only server having matching uris will be returned
306		"""
307	1	if uris is None:
308	1	uris = []
309	1	params = ua.FindServersParameters()
310	1	params.EndpointUrl = self.server_url.geturl()
311	1	params.ServerUris = uris
312	1	return self.uaclient.find_servers(params)
313
314	1	def find_servers_on_network(self):
315		params = ua.FindServersOnNetworkParameters()
316		return self.uaclient.find_servers_on_network(params)
317
318	1	def create_session(self):
319		"""
320		send a CreateSessionRequest to server with reasonable parameters.
321		If you want o modify settings look at code of this methods
322		and make your own
323		"""
324	1	desc = ua.ApplicationDescription()
325	1	desc.ApplicationUri = self.application_uri
326	1	desc.ProductUri = self.product_uri
327	1	desc.ApplicationName = ua.LocalizedText(self.name)
328	1	desc.ApplicationType = ua.ApplicationType.Client
329
330	1	params = ua.CreateSessionParameters()
331	1	nonce = utils.create_nonce(32) # at least 32 random bytes for server to prove possession of private key (specs part 4, 5.6.2.2)
332	1	params.ClientNonce = nonce
333	1	params.ClientCertificate = self.security_policy.client_certificate
334	1	params.ClientDescription = desc
335	1	params.EndpointUrl = self.server_url.geturl()
336	1	params.SessionName = self.description + " Session" + str(self._session_counter)
337	1	params.RequestedSessionTimeout = 3600000
338	1	params.MaxResponseMessageSize = 0 # means no max size
339	1	response = self.uaclient.create_session(params)
340	1	if self.security_policy.client_certificate is None:
341	1	data = nonce
342		else:
343	1	data = self.security_policy.client_certificate + nonce
344	1	self.security_policy.asymmetric_cryptography.verify(data, response.ServerSignature.Signature)
345	1	self._server_nonce = response.ServerNonce
346	1	if not self.security_policy.server_certificate:
347	1	self.security_policy.server_certificate = response.ServerCertificate
348	1	elif self.security_policy.server_certificate != response.ServerCertificate:
349		raise ua.UaError("Server certificate mismatch")
350		# remember PolicyId's: we will use them in activate_session()
351	1	ep = Client.find_endpoint(response.ServerEndpoints, self.security_policy.Mode, self.security_policy.URI)
352	1	self._policy_ids = ep.UserIdentityTokens
353	1	self.session_timeout = response.RevisedSessionTimeout
354	1	self.keepalive = KeepAlive(self, min(self.session_timeout, self.secure_channel_timeout) * 0.7) # 0.7 is from spec
355	1	self.keepalive.start()
356	1	return response
357
358	1	def server_policy_id(self, token_type, default):
359		"""
360		Find PolicyId of server's UserTokenPolicy by token_type.
361		Return default if there's no matching UserTokenPolicy.
362		"""
363	1	for policy in self._policy_ids:
364	1	if policy.TokenType == token_type:
365	1	return policy.PolicyId
366		return default
367
368	1	def server_policy_uri(self, token_type):
369		"""
370		Find SecurityPolicyUri of server's UserTokenPolicy by token_type.
371		If SecurityPolicyUri is empty, use default SecurityPolicyUri
372		of the endpoint
373		"""
374	1	for policy in self._policy_ids:
375	1	if policy.TokenType == token_type:
376	1	if policy.SecurityPolicyUri:
377		return policy.SecurityPolicyUri
378		else: # empty URI means "use this endpoint's policy URI"
379	1	return self.security_policy.URI
380		return self.security_policy.URI
381
382	1	def activate_session(self, username=None, password=None, certificate=None):
383		"""
384		Activate session using either username and password or private_key
385		"""
386	1	params = ua.ActivateSessionParameters()
387	1	challenge = b""
388	1	if self.security_policy.server_certificate is not None:
389	1	challenge += self.security_policy.server_certificate
390	1	if self._server_nonce is not None:
391	1	challenge += self._server_nonce
392	1	params.ClientSignature.Algorithm = b"http://www.w3.org/2000/09/xmldsig#rsa-sha1"
393	1	params.ClientSignature.Signature = self.security_policy.asymmetric_cryptography.signature(challenge)
394	1	params.LocaleIds.append("en")
395	1	if not username and not certificate:
396	1	self._add_anonymous_auth(params)
397	1	elif certificate:
398		self._add_certificate_auth(params, certificate, challenge)
399		else:
400	1	self._add_user_auth(params, username, password)
401	1	return self.uaclient.activate_session(params)
402
403	1	def _add_anonymous_auth(self, params):
404	1	params.UserIdentityToken = ua.AnonymousIdentityToken()
405	1	params.UserIdentityToken.PolicyId = self.server_policy_id(ua.UserTokenType.Anonymous, b"anonymous")
406
407	1	def _add_certificate_auth(self, params, certificate, challenge):
408		params.UserIdentityToken = ua.X509IdentityToken()
409		params.UserIdentityToken.PolicyId = self.server_policy_id(ua.UserTokenType.Certificate, b"certificate_basic256")
410		params.UserIdentityToken.CertificateData = uacrypto.der_from_x509(certificate)
411		# specs part 4, 5.6.3.1: the data to sign is created by appending
412		# the last serverNonce to the serverCertificate
413		sig = uacrypto.sign_sha1(self.user_private_key, challenge)
414		params.UserTokenSignature = ua.SignatureData()
415		params.UserTokenSignature.Algorithm = b"http://www.w3.org/2000/09/xmldsig#rsa-sha1"
416		params.UserTokenSignature.Signature = sig
417
418	1	def _add_user_auth(self, params, username, password):
419	1	params.UserIdentityToken = ua.UserNameIdentityToken()
420	1	params.UserIdentityToken.UserName = username
421	1	policy_uri = self.server_policy_uri(ua.UserTokenType.UserName)
422	1	if not policy_uri or policy_uri == security_policies.POLICY_NONE_URI:
423		# see specs part 4, 7.36.3: if the token is NOT encrypted,
424		# then the password only contains UTF-8 encoded password
425		# and EncryptionAlgorithm is null
426	1	if self.server_url.password:
427		self.logger.warning("Sending plain-text password")
428		params.UserIdentityToken.Password = password
429	1	params.UserIdentityToken.EncryptionAlgorithm = ''
430		elif self.server_url.password:
431		data, uri = self._encrypt_password(password, policy_uri)
432		params.UserIdentityToken.Password = data
433		params.UserIdentityToken.EncryptionAlgorithm = uri
434	1	params.UserIdentityToken.PolicyId = self.server_policy_id(ua.UserTokenType.UserName, b"username_basic256")
435
436	1	def _encrypt_password(self, password, policy_uri):
437		pubkey = uacrypto.x509_from_der(self.security_policy.server_certificate).public_key()
438		# see specs part 4, 7.36.3: if the token is encrypted, password
439		# shall be converted to UTF-8 and serialized with server nonce
440		passwd = password.encode("utf8")
441		if self._server_nonce is not None:
442		passwd += self._server_nonce
443		etoken = ua.ua_binary.Primitives.Bytes.pack(passwd)
444		data, uri = security_policies.encrypt_asymmetric(pubkey, etoken, policy_uri)
445		return data, uri
446
447	1	def close_session(self):
448		"""
449		Close session
450		"""
451	1	if self.keepalive:
452	1	self.keepalive.stop()
453	1	return self.uaclient.close_session(True)
454
455	1	def get_root_node(self):
456	1	return self.get_node(ua.TwoByteNodeId(ua.ObjectIds.RootFolder))
457
458	1	def get_objects_node(self):
459	1	return self.get_node(ua.TwoByteNodeId(ua.ObjectIds.ObjectsFolder))
460
461	1	def get_server_node(self):
462	1	return self.get_node(ua.FourByteNodeId(ua.ObjectIds.Server))
463
464	1	def get_node(self, nodeid):
465		"""
466		Get node using NodeId object or a string representing a NodeId
467		"""
468	1	return Node(self.uaclient, nodeid)
469
470	1	def create_subscription(self, period, handler):
471		"""
472		Create a subscription.
473		returns a Subscription object which allow
474		to subscribe to events or data on server
475		handler argument is a class with data_change and/or event methods.
476		period argument is either a publishing interval in seconds or a
477		CreateSubscriptionParameters instance. The second option should be used,
478		if the opcua-server has problems with the default options.
479		These methods will be called when notfication from server are received.
480		See example-client.py.
481		Do not do expensive/slow or network operation from these methods
482		since they are called directly from receiving thread. This is a design choice,
483		start another thread if you need to do such a thing.
484		"""
485
486	1	if isinstance(period, ua.CreateSubscriptionParameters):
487		return Subscription(self.uaclient, period, handler)
488	1	params = ua.CreateSubscriptionParameters()
489	1	params.RequestedPublishingInterval = period
490	1	params.RequestedLifetimeCount = 10000
491	1	params.RequestedMaxKeepAliveCount = 3000
492	1	params.MaxNotificationsPerPublish = 10000
493	1	params.PublishingEnabled = True
494	1	params.Priority = 0
495	1	return Subscription(self.uaclient, params, handler)
496
497	1	def get_namespace_array(self):
498	1	ns_node = self.get_node(ua.NodeId(ua.ObjectIds.Server_NamespaceArray))
499	1	return ns_node.get_value()
500
501	1	def get_namespace_index(self, uri):
502	1	uries = self.get_namespace_array()
503	1	return uries.index(uri)
504
505	1	def delete_nodes(self, nodes, recursive=False):
506	1	return delete_nodes(self.uaclient, nodes, recursive)
507
508	1	def import_xml(self, path):
509		"""
510		Import nodes defined in xml
511		"""
512	1	importer = XmlImporter(self)
513	1	return importer.import_xml(path)
514
515	1	def export_xml(self, nodes, path):
516		"""
517		Export defined nodes to xml
518		"""
519	1	exp = XmlExporter(self)
520	1	exp.build_etree(nodes)
521	1	return exp.write_xml(path)
522
523	1	def register_namespace(self, uri):
524		"""
525		Register a new namespace. Nodes should in custom namespace, not 0.
526		This method is mainly implemented for symetry with server
527		"""
528	1	ns_node = self.get_node(ua.NodeId(ua.ObjectIds.Server_NamespaceArray))
529	1	uries = ns_node.get_value()
530	1	if uri in uries:
531	1	return uries.index(uri)
532	1	uries.append(uri)
533	1	ns_node.set_value(uries)
534	1	return len(uries) - 1
535
536
537

FreeOpcUa / python-opcua

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