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from __future__ import division # support for python2 |
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import os |
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from threading import Thread, Condition |
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import logging |
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try: |
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from urllib.parse import urlparse |
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except ImportError: # support for python2 |
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from urlparse import urlparse |
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from opcua import uaprotocol as ua |
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from opcua import BinaryClient, Node, Subscription |
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from opcua import utils |
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from opcua import uacrypto |
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class KeepAlive(Thread): |
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""" |
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Used by Client to keep session opened. |
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OPCUA defines timeout both for sessions and secure channel |
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""" |
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def __init__(self, client, timeout): |
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Thread.__init__(self) |
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self.logger = logging.getLogger(__name__) |
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if timeout == 0: # means no timeout bu we do not trust such servers |
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timeout = 360000 |
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self.timeout = timeout |
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self.client = client |
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self._dostop = False |
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self._cond = Condition() |
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1 |
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def run(self): |
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self.logger.debug("starting keepalive thread with period of %s milliseconds", self.timeout) |
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server_state = self.client.get_node(ua.FourByteNodeId(ua.ObjectIds.Server_ServerStatus_State)) |
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36
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1 |
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while not self._dostop: |
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with self._cond: |
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self._cond.wait(self.timeout / 1000) |
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if self._dostop: |
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break |
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self.logger.debug("renewing channel") |
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self.client.open_secure_channel(renew=True) |
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val = server_state.get_value() |
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self.logger.debug("server state is: %s ", val) |
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self.logger.debug("keepalive thread has stopped") |
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def stop(self): |
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self.logger.debug("stoping keepalive thread") |
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with self._cond: |
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self._cond.notify_all() |
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self._dostop = True |
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class Client(object): |
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""" |
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High level client to connect to an OPC-UA server. |
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This class makes it easy to connect and browse address space. |
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It attemps to expose as much functionality as possible |
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but if you want to do to special things you will probably need |
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to work with the BinaryClient object, available as self.bclient |
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which offers a raw OPC-UA interface. |
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""" |
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def __init__(self, url, timeout=1): |
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""" |
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used url argument to connect to server. |
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if you are unsure of url, write at least hostname and port |
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and call get_endpoints |
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timeout is the timeout to get an answer for requests to server |
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public member of this call are available to be set by API users |
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73
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""" |
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self.logger = logging.getLogger(__name__) |
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self.server_url = urlparse(url) |
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self.name = "Pure Python Client" |
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self.description = self.name |
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78
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self.application_uri = "urn:freeopcua:client" |
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self.product_uri = "urn:freeopcua.github.no:client" |
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80
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self.security_policy_uri = "http://opcfoundation.org/UA/SecurityPolicy#None" |
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self.security_mode = ua.MessageSecurityMode.None_ |
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self.secure_channel_id = None |
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self.default_timeout = 3600000 |
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84
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self.secure_channel_timeout = self.default_timeout |
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85
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self.session_timeout = self.default_timeout |
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86
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self._policy_ids = [] |
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87
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self.server_certificate = "" |
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self.client_certificate = "" |
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self.private_key = "" |
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self.bclient = BinaryClient(timeout) |
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self._nonce = None |
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self._session_counter = 1 |
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self.keepalive = None |
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def load_client_certificate(self, path): |
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""" |
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load our certificate from file, either pem or der |
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""" |
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_, ext = os.path.splitext(path) |
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100
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with open(path, "br") as f: |
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self.client_certificate = f.read() |
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if ext == ".pem": |
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self.client_certificate = uacrypto.dem_to_der(self.client_certificate) |
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104
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105
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def load_private_key(self, path): |
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with open(path, "br") as f: |
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self.private_key = f.read() |
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def get_server_endpoints(self): |
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""" |
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Connect, ask server for endpoints, and disconnect |
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""" |
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self.connect_socket() |
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self.send_hello() |
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115
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self.open_secure_channel() |
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endpoints = self.get_endpoints() |
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self.close_secure_channel() |
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self.disconnect_socket() |
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return endpoints |
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120
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121
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1 |
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def find_all_servers(self): |
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122
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""" |
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123
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Connect, ask server for a list of known servers, and disconnect |
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""" |
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self.connect_socket() |
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self.send_hello() |
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self.open_secure_channel() |
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servers = self.find_servers() |
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self.close_secure_channel() |
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self.disconnect_socket() |
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return servers |
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def connect(self): |
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""" |
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High level method |
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Connect, create and activate session |
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""" |
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138
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self.connect_socket() |
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self.send_hello() |
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self.open_secure_channel() |
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141
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self.create_session() |
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142
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self.activate_session(username=self.server_url.username, password=self.server_url.password, certificate=self.client_certificate) |
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144
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def disconnect(self): |
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145
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""" |
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146
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High level method |
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147
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Close session, secure channel and socket |
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148
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""" |
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149
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self.close_session() |
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150
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self.close_secure_channel() |
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151
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self.disconnect_socket() |
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153
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1 |
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def connect_socket(self): |
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154
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""" |
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155
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connect to socket defined in url |
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""" |
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157
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1 |
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self.bclient.connect_socket(self.server_url.hostname, self.server_url.port) |
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159
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1 |
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def disconnect_socket(self): |
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160
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self.bclient.disconnect_socket() |
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161
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162
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1 |
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def send_hello(self): |
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163
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""" |
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164
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Send OPC-UA hello to server |
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165
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""" |
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166
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1 |
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ack = self.bclient.send_hello(self.server_url.geturl()) |
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167
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# FIXME check ack |
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168
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169
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1 |
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def open_secure_channel(self, renew=False): |
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170
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""" |
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171
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Open secure channel, if renew is True, renew channel |
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172
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""" |
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173
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params = ua.OpenSecureChannelParameters() |
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174
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1 |
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params.ClientProtocolVersion = 0 |
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175
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1 |
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params.RequestType = ua.SecurityTokenRequestType.Issue |
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176
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if renew: |
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177
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params.RequestType = ua.SecurityTokenRequestType.Renew |
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178
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1 |
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params.SecurityMode = self.security_mode |
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params.RequestedLifetime = self.secure_channel_timeout |
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180
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1 |
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params.ClientNonce = '\x00' |
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181
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1 |
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result = self.bclient.open_secure_channel(params) |
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182
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1 |
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self.secure_channel_timeout = result.SecurityToken.RevisedLifetime |
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183
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184
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1 |
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def close_secure_channel(self): |
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185
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1 |
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return self.bclient.close_secure_channel() |
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186
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187
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1 |
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def get_endpoints(self): |
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188
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1 |
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params = ua.GetEndpointsParameters() |
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189
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1 |
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params.EndpointUrl = self.server_url.geturl() |
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190
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1 |
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return self.bclient.get_endpoints(params) |
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191
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192
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1 |
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def find_servers(self): |
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193
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params = ua.FindServersParameters() |
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194
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return self.bclient.find_servers(params) |
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195
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196
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1 |
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def create_session(self): |
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197
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1 |
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desc = ua.ApplicationDescription() |
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198
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1 |
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desc.ApplicationUri = self.application_uri |
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199
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1 |
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desc.ProductUri = self.product_uri |
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200
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1 |
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desc.ApplicationName = ua.LocalizedText(self.name) |
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201
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1 |
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desc.ApplicationType = ua.ApplicationType.Client |
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202
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203
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1 |
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params = ua.CreateSessionParameters() |
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204
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1 |
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params.ClientNonce = utils.create_nonce() |
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205
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1 |
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params.ClientCertificate = b'' |
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206
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1 |
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params.ClientDescription = desc |
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207
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1 |
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params.EndpointUrl = self.server_url.geturl() |
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208
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1 |
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params.SessionName = self.description + " Session" + str(self._session_counter) |
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209
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1 |
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params.RequestedSessionTimeout = 3600000 |
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210
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1 |
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params.MaxResponseMessageSize = 0 # means no max size |
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211
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1 |
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params.ClientCertificate = self.client_certificate |
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212
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1 |
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response = self.bclient.create_session(params) |
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213
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1 |
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self.server_certificate = response.ServerCertificate |
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214
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1 |
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for ep in response.ServerEndpoints: |
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215
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1 |
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if ep.SecurityMode == self.security_mode: |
|
216
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# remember PolicyId's: we will use them in activate_session() |
|
217
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1 |
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self._policy_ids = ep.UserIdentityTokens |
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218
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1 |
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self.session_timeout = response.RevisedSessionTimeout |
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219
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1 |
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self.keepalive = KeepAlive(self, min(self.session_timeout, self.secure_channel_timeout) * 0.7) # 0.7 is from spec |
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220
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1 |
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self.keepalive.start() |
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221
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1 |
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return response |
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222
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223
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1 |
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def activate_session(self, username=None, password=None, certificate=None): |
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224
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""" |
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225
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Activate session using either username and password or private_key |
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226
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""" |
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227
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1 |
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params = ua.ActivateSessionParameters() |
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228
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1 |
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params.LocaleIds.append("en") |
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229
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1 |
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if not username and not certificate: |
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230
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1 |
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params.UserIdentityToken = ua.AnonymousIdentityToken() |
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231
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1 |
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params.UserIdentityToken.PolicyId = b"anonymous" |
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232
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1 |
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elif certificate: |
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233
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params.UserIdentityToken = ua.X509IdentityToken() |
|
234
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params.UserIdentityToken.PolicyId = b"certificate_basic256" |
|
235
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params.UserIdentityToken.CertificateData = certificate |
|
236
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sig = uacrypto.sign_sha1(self.private_key, certificate) |
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237
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params.UserTokenSignature = ua.SignatureData() |
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238
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params.UserTokenSignature.Algorithm = b"http://www.w3.org/2000/09/xmldsig#rsa-sha1" |
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239
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params.UserTokenSignature.Signature = sig |
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240
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else: |
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241
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1 |
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params.UserIdentityToken = ua.UserNameIdentityToken() |
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242
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1 |
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params.UserIdentityToken.UserName = username |
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243
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1 |
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if self.server_url.password: |
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244
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pubkey = uacrypto.pubkey_from_dercert(self.server_certificate) |
|
245
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data = uacrypto.encrypt_rsa_oaep(pubkey, bytes(password, "utf8")) |
|
246
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params.UserIdentityToken.Password = data |
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247
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1 |
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params.UserIdentityToken.PolicyId = b"username_basic256" |
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248
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1 |
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params.UserIdentityToken.EncryptionAlgorithm = 'http://www.w3.org/2001/04/xmlenc#rsa-oaep' |
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249
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1 |
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return self.bclient.activate_session(params) |
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250
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251
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1 |
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def close_session(self): |
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252
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""" |
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253
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Close session |
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254
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""" |
|
255
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1 |
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if self.keepalive: |
|
256
|
1 |
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self.keepalive.stop() |
|
257
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1 |
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return self.bclient.close_session(True) |
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258
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259
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1 |
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def get_root_node(self): |
|
260
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1 |
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return self.get_node(ua.TwoByteNodeId(ua.ObjectIds.RootFolder)) |
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261
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|
262
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1 |
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def get_objects_node(self): |
|
263
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1 |
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return self.get_node(ua.TwoByteNodeId(ua.ObjectIds.ObjectsFolder)) |
|
264
|
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|
|
265
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1 |
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def get_server_node(self): |
|
266
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1 |
|
return self.get_node(ua.TwoByteNodeId(ua.ObjectIds.Server)) |
|
267
|
|
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|
|
268
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1 |
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def get_node(self, nodeid): |
|
269
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|
""" |
|
270
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|
|
Get node using NodeId object or a string representing a NodeId |
|
271
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|
|
""" |
|
272
|
1 |
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return Node(self.bclient, nodeid) |
|
273
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|
274
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1 |
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def create_subscription(self, period, handler): |
|
275
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""" |
|
276
|
|
|
Create a subscription. |
|
277
|
|
|
returns a Subscription object which allow |
|
278
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|
|
to subscribe to events or data on server |
|
279
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|
|
handler argument is a class with data_change and/or event methods. |
|
280
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|
|
These methods will be called when notfication from server are received. |
|
281
|
|
|
See example-client.py. |
|
282
|
|
|
Do not do expensive/slow or network operation from these methods |
|
283
|
|
|
since they are called directly from receiving thread. This is a design choice, |
|
284
|
|
|
start another thread if you need to do such a thing. |
|
285
|
|
|
""" |
|
286
|
1 |
|
params = ua.CreateSubscriptionParameters() |
|
287
|
1 |
|
params.RequestedPublishingInterval = period |
|
288
|
1 |
|
params.RequestedLifetimeCount = 3000 |
|
289
|
1 |
|
params.RequestedMaxKeepAliveCount = 10000 |
|
290
|
1 |
|
params.MaxNotificationsPerPublish = 4294967295 |
|
291
|
1 |
|
params.PublishingEnabled = True |
|
292
|
1 |
|
params.Priority = 0 |
|
293
|
1 |
|
return Subscription(self.bclient, params, handler) |
|
294
|
|
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|
|
295
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1 |
|
def get_namespace_array(self): |
|
296
|
1 |
|
ns_node = self.get_node(ua.NodeId(ua.ObjectIds.Server_NamespaceArray)) |
|
297
|
1 |
|
return ns_node.get_value() |
|
298
|
|
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|
299
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1 |
|
def get_namespace_index(self, uri): |
|
300
|
1 |
|
uries = self.get_namespace_array() |
|
301
|
|
|
return uries.index(uri) |
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302
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FreeOpcUa /
python-opcua
