class UaClient(object):
"""
OPC-Ua client specialized for the need of GUI client
return exactly what GUI needs, no customization possible
"""
def __init__(self):
self.settings = QSettings()
self.client = None
self._connected = False
self._datachange_sub = None
self._event_sub = None
self._subs_dc = {}
self._subs_ev = {}
self.security_mode = None
self.security_policy = None
self.certificate_path = None
self.private_key_path = None
def _reset(self):
self.client = None
self._connected = False
self._datachange_sub = None
self._event_sub = None
self._subs_dc = {}
self._subs_ev = {}
@staticmethod
def get_endpoints(uri):
client = Client(uri, timeout=2)
edps = client.connect_and_get_server_endpoints()
for i, ep in enumerate(edps, start=1):
logger.info('Endpoint %s:', i)
for (n, v) in endpoint_to_strings(ep):
logger.info(' %s: %s', n, v)
logger.info('')
return edps
def load_security_settings(self, uri):
self.security_mode = None
self.security_policy = None
self.certificate_path = None
self.private_key_path = None
mysettings = self.settings.value("security_settings", None)
if mysettings is None:
return
if uri in mysettings:
mode, policy, cert, key = mysettings[uri]
self.security_mode = mode
self.security_policy = policy
self.certificate_path = cert
self.private_key_path = key
def save_security_settings(self, uri):
mysettings = self.settings.value("security_settings", None)
if mysettings is None:
mysettings = {}
mysettings[uri] = [
self.security_mode, self.security_policy, self.certificate_path,
self.private_key_path
]
self.settings.setValue("security_settings", mysettings)
def get_node(self, nodeid):
return self.client.get_node(nodeid)
def connect(self, uri):
self.disconnect()
logger.info("Connecting to %s with parameters %s, %s, %s, %s", uri,
self.security_mode, self.security_policy,
self.certificate_path, self.private_key_path)
self.client = Client(uri)
if self.security_mode is not None and self.security_policy is not None:
self.client.set_security(getattr(
crypto.security_policies,
'SecurityPolicy' + self.security_policy),
self.certificate_path,
self.private_key_path,
mode=getattr(ua.MessageSecurityMode,
self.security_mode))
self.client.connect()
self._connected = True
self.client.load_enums()
self.client.load_type_definitions()
self.save_security_settings(uri)
def disconnect(self):
if self._connected:
print("Disconnecting from server")
self._connected = False
try:
self.client.disconnect()
finally:
self._reset()
def subscribe_datachange(self, node, handler):
if not self._datachange_sub:
self._datachange_sub = self.client.create_subscription(
500, handler)
handle = self._datachange_sub.subscribe_data_change(node)
self._subs_dc[node.nodeid] = handle
return handle
def unsubscribe_datachange(self, node):
self._datachange_sub.unsubscribe(self._subs_dc[node.nodeid])
def subscribe_events(self, node, handler):
if not self._event_sub:
print("subscirbing with handler: ", handler, dir(handler))
self._event_sub = self.client.create_subscription(500, handler)
handle = self._event_sub.subscribe_events(node)
self._subs_ev[node.nodeid] = handle
return handle
def unsubscribe_events(self, node):
self._event_sub.unsubscribe(self._subs_ev[node.nodeid])
def get_node_attrs(self, node):
if not isinstance(node, Node):
node = self.client.get_node(node)
attrs = node.get_attributes([
ua.AttributeIds.DisplayName, ua.AttributeIds.BrowseName,
ua.AttributeIds.NodeId
])
return node, [attr.Value.Value.to_string() for attr in attrs]
@staticmethod
def get_children(node):
descs = node.get_children_descriptions()
descs.sort(key=lambda x: x.BrowseName)
return descs
