opcua.client.UASocketClient._write_socket()

Complexity

Conditions

2

Size

Total Lines

12

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	12
CRAP Score	2

1 Method

Rating	Name	Duplication	Size	Complexity
A	opcua.client.UASocketClient.disconnect_socket()	0	4	1

"""
Low level binary client
"""

import logging
import socket
from threading import Thread, Lock
from concurrent.futures import Future
from functools import partial

from opcua import ua
from opcua.common import utils

class UASocketClient(object):
    """
    handle socket connection and send ua messages
    timeout is the timeout used while waiting for an ua answer from server
    """
    def __init__(self, timeout=1, security_policy=ua.SecurityPolicy()):
        self.logger = logging.getLogger(__name__ + "Socket")
        self._thread = None
        self._lock = Lock()
        self.timeout = timeout
        self._socket = None
        self._do_stop = False
        self.authentication_token = ua.NodeId()
        self._request_id = 0
        self._request_handle = 0
        self._callbackmap = {}
        self._connection = ua.SecureConnection(security_policy)

    def start(self):
        """
        Start receiving thread.
        this is called automatically in connect and
        should not be necessary to call directly
        """
        self._thread = Thread(target=self._run)
        self._thread.start()

    def _send_request(self, request, callback=None, timeout=1000, message_type=ua.MessageType.SecureMessage):
        """
        send request to server, lower-level method
        timeout is the timeout written in ua header
        returns future
        """
        with self._lock:
            request.RequestHeader = self._create_request_header(timeout)
            try:
                binreq = request.to_binary()
            except:
                # reset reqeust handle if any error
                # see self._create_request_header
                self._request_handle -= 1
                raise
            self._request_id += 1
            future = Future()
            if callback:
                future.add_done_callback(callback)
            self._callbackmap[self._request_id] = future
            msg = self._connection.message_to_binary(binreq,
                    message_type, self._request_id)
            self._socket.write(msg)
        return future

    def send_request(self, request, callback=None, timeout=1000, message_type=ua.MessageType.SecureMessage):
        """
        send request to server.
        timeout is the timeout written in ua header
        returns response object if no callback is provided
        """
        future = self._send_request(request, callback, timeout, message_type)
        if not callback:
            data = future.result(self.timeout)
            self.check_answer(data, " in response to " + request.__class__.__name__)
            return data

    def check_answer(self, data, context):
        data = data.copy()
        typeid = ua.NodeId.from_binary(data)
        if typeid == ua.FourByteNodeId(ua.ObjectIds.ServiceFault_Encoding_DefaultBinary):
            self.logger.warning("ServiceFault from server received %s", context)
            hdr = ua.ResponseHeader.from_binary(data)
            hdr.ServiceResult.check()
            return False
        return True

    def _run(self):
        self.logger.info("Thread started")
        while not self._do_stop:
            try:
                self._receive()
            except ua.utils.SocketClosedException:
                self.logger.info("Socket has closed connection")
                break
        self.logger.info("Thread ended")

    def _receive(self):
        msg = self._connection.receive_from_socket(self._socket)
        if msg is None:
            return
        elif isinstance(msg, ua.Message):
            self._call_callback(msg.request_id(), msg.body())
        elif isinstance(msg, ua.Acknowledge):
            self._call_callback(0, msg)
        elif isinstance(msg, ua.ErrorMessage):
            self.logger.warning("Received an error: {}".format(msg))
        else:
            raise Exception("Unsupported message type: {}".format(msg))

    def _call_callback(self, request_id, body):
        with self._lock:
            future = self._callbackmap.pop(request_id, None)
            if future is None:
                raise Exception("No future object found for request: {}, callbacks in list are {}".format(request_id, self._callbackmap.keys()))
        future.set_result(body)

    def _create_request_header(self, timeout=1000):
        hdr = ua.RequestHeader()
        hdr.AuthenticationToken = self.authentication_token
        self._request_handle += 1
        hdr.RequestHandle = self._request_handle
        hdr.TimeoutHint = timeout
        return hdr

    def connect_socket(self, host, port):
        """
        connect to server socket and start receiving thread
        """
        self.logger.info("opening connection")
        sock = socket.create_connection((host, port))
        sock.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)  # nodelay ncessary to avoid packing in one frame, some servers do not like it
        self._socket = utils.SocketWrapper(sock)
        self.start()

    def disconnect_socket(self):
        self.logger.info("stop request")
        self._do_stop = True
        self._socket.socket.shutdown(socket.SHUT_WR)

    def send_hello(self, url):
        hello = ua.Hello()
        hello.EndpointUrl = url
        future = Future()
        with self._lock:
            self._callbackmap[0] = future
        binmsg = self._connection.tcp_to_binary(ua.MessageType.Hello, hello)
        self._socket.write(binmsg)
        ack = future.result(self.timeout)
        return ack

    def open_secure_channel(self, params):
        self.logger.info("open_secure_channel")
        request = ua.OpenSecureChannelRequest()
        request.Parameters = params
        future = self._send_request(request, message_type=ua.MessageType.SecureOpen)

        response = ua.OpenSecureChannelResponse.from_binary(future.result(self.timeout))
        response.ResponseHeader.ServiceResult.check()
        self._connection.set_security_token(response.Parameters.SecurityToken)
        return response.Parameters

    def close_secure_channel(self):
        """
        close secure channel. It seems to trigger a shutdown of socket
        in most servers, so be prepare to reconnect.
        OPC UA specs Part 6, 7.1.4 say that Server does not send a CloseSecureChannel response and should just close socket
        """
        self.logger.info("close_secure_channel")
        request = ua.CloseSecureChannelRequest()
        future = self._send_request(request, message_type=ua.MessageType.SecureClose)
        with self._lock:
            # don't expect any more answers
            future.cancel()
            self._callbackmap.clear()

        # some servers send a response here, most do not ... so we ignore



class BinaryClient(object):

    """
    low level OPC-UA client.
    implement all(well..one day) methods defined in opcua spec
    taking in argument the structures defined in opcua spec
    in python most of the structures are defined in
    uaprotocol_auto.py and uaprotocol_hand.py
    """

    def __init__(self, timeout=1):
        self.logger = logging.getLogger(__name__)
        # _publishcallbacks should be accessed in recv thread only
        self._publishcallbacks = {}
        self._timeout = timeout
        self._uasocket = None
        self._security_policy = ua.SecurityPolicy()

    def set_security(self, policy):
        self._security_policy = policy

    def connect_socket(self, host, port):
        """
        connect to server socket and start receiving thread
        """
        self._uasocket = UASocketClient(self._timeout, security_policy=self._security_policy)
        return self._uasocket.connect_socket(host, port)

    def disconnect_socket(self):
        return self._uasocket.disconnect_socket()

    def send_hello(self, url):
        return self._uasocket.send_hello(url)

    def open_secure_channel(self, params):
        return self._uasocket.open_secure_channel(params)

    def close_secure_channel(self):
        """
        close secure channel. It seems to trigger a shutdown of socket
        in most servers, so be prepare to reconnect
        """
        return self._uasocket.close_secure_channel()

    def create_session(self, parameters):
        self.logger.info("create_session")
        request = ua.CreateSessionRequest()
        request.Parameters = parameters
        data = self._uasocket.send_request(request)
        response = ua.CreateSessionResponse.from_binary(data)
        response.ResponseHeader.ServiceResult.check()
        self._uasocket.authentication_token = response.Parameters.AuthenticationToken
        return response.Parameters

    def activate_session(self, parameters):
        self.logger.info("activate_session")
        request = ua.ActivateSessionRequest()
        request.Parameters = parameters
        data = self._uasocket.send_request(request)
        response = ua.ActivateSessionResponse.from_binary(data)
        response.ResponseHeader.ServiceResult.check()
        return response.Parameters

    def close_session(self, deletesubscriptions):
        self.logger.info("close_session")
        request = ua.CloseSessionRequest()
        request.DeleteSubscriptions = deletesubscriptions
        data = self._uasocket.send_request(request)
        ua.CloseSessionResponse.from_binary(data)
        # response.ResponseHeader.ServiceResult.check() #disabled, it seems we sent wrong session Id, but where is the sessionId supposed to be sent???

    def browse(self, parameters):
        self.logger.info("browse")
        request = ua.BrowseRequest()
        request.Parameters = parameters
        data = self._uasocket.send_request(request)
        response = ua.BrowseResponse.from_binary(data)
        response.ResponseHeader.ServiceResult.check()
        return response.Results

    def read(self, parameters):
        self.logger.info("read")
        request = ua.ReadRequest()
        request.Parameters = parameters
        data = self._uasocket.send_request(request)
        response = ua.ReadResponse.from_binary(data)
        response.ResponseHeader.ServiceResult.check()
        # cast to Enum attributes that need to
        for idx, rv in enumerate(parameters.NodesToRead):
            if rv.AttributeId == ua.AttributeIds.NodeClass:
                dv = response.Results[idx]
                if dv.StatusCode.is_good():
                    dv.Value.Value = ua.NodeClass(dv.Value.Value)
            elif rv.AttributeId == ua.AttributeIds.ValueRank:
                dv = response.Results[idx]
                if dv.StatusCode.is_good() and dv.Value.Value in (-3, -2, -1, 0, 1, 2, 3, 4):
                    dv.Value.Value = ua.ValueRank(dv.Value.Value)
        return response.Results

    def write(self, params):
        self.logger.info("read")
        request = ua.WriteRequest()
        request.Parameters = params
        data = self._uasocket.send_request(request)
        response = ua.WriteResponse.from_binary(data)
        response.ResponseHeader.ServiceResult.check()
        return response.Results

    def get_endpoints(self, params):
        self.logger.info("get_endpoint")
        request = ua.GetEndpointsRequest()
        request.Parameters = params
        data = self._uasocket.send_request(request)
        response = ua.GetEndpointsResponse.from_binary(data)
        response.ResponseHeader.ServiceResult.check()
        return response.Endpoints

    def find_servers(self, params):
        self.logger.info("find_servers")
        request = ua.FindServersRequest()
        request.Parameters = params
        data = self._uasocket.send_request(request)
        response = ua.FindServersResponse.from_binary(data)
        response.ResponseHeader.ServiceResult.check()
        return response.Servers

    def find_servers_on_network(self, params):
        self.logger.info("find_servers_on_network")
        request = ua.FindServersOnNetworkRequest()
        request.Parameters = params
        data = self._uasocket.send_request(request)
        response = ua.FindServersOnNetworkResponse.from_binary(data)
        response.ResponseHeader.ServiceResult.check()
        return response.Parameters

    def register_server(self, registered_server):
        self.logger.info("register_server")
        request = ua.RegisterServerRequest()
        request.Server = registered_server
        data = self._uasocket.send_request(request)
        response = ua.RegisterServerResponse.from_binary(data)
        response.ResponseHeader.ServiceResult.check()
        # nothing to return for this service

    def register_server2(self, params):
        self.logger.info("register_server2")
        request = ua.RegisterServer2Request()
        request.Parameters = params
        data = self._uasocket.send_request(request)
        response = ua.RegisterServer2Response.from_binary(data)
        response.ResponseHeader.ServiceResult.check()
        return response.ConfigurationResults

    def translate_browsepaths_to_nodeids(self, browsepaths):
        self.logger.info("translate_browsepath_to_nodeid")
        request = ua.TranslateBrowsePathsToNodeIdsRequest()
        request.Parameters.BrowsePaths = browsepaths
        data = self._uasocket.send_request(request)
        response = ua.TranslateBrowsePathsToNodeIdsResponse.from_binary(data)
        response.ResponseHeader.ServiceResult.check()
        return response.Results

    def create_subscription(self, params, callback):
        self.logger.info("create_subscription")
        request = ua.CreateSubscriptionRequest()
        request.Parameters = params
        resp_fut = Future()
        mycallbak = partial(self._create_subscription_callback, callback, resp_fut)
        self._uasocket.send_request(request, mycallbak)
        return resp_fut.result(self._timeout)

    def _create_subscription_callback(self, pub_callback, resp_fut, data_fut):
        self.logger.info("_create_subscription_callback")
        data = data_fut.result()
        response = ua.CreateSubscriptionResponse.from_binary(data)
        response.ResponseHeader.ServiceResult.check()
        self._publishcallbacks[response.Parameters.SubscriptionId] = pub_callback
        resp_fut.set_result(response.Parameters)

    def delete_subscriptions(self, subscriptionids):
        self.logger.info("delete_subscription")
        request = ua.DeleteSubscriptionsRequest()
        request.Parameters.SubscriptionIds = subscriptionids
        resp_fut = Future()
        mycallbak = partial(self._delete_subscriptions_callback, subscriptionids, resp_fut)
        self._uasocket.send_request(request, mycallbak)
        return resp_fut.result(self._timeout)

    def _delete_subscriptions_callback(self, subscriptionids, resp_fut, data_fut):
        self.logger.info("_delete_subscriptions_callback")
        data = data_fut.result()
        response = ua.DeleteSubscriptionsResponse.from_binary(data)
        response.ResponseHeader.ServiceResult.check()
        for sid in subscriptionids:
            self._publishcallbacks.pop(sid)
        resp_fut.set_result(response.Results)

    def publish(self, acks=None):
        self.logger.info("publish")
        if acks is None:
            acks = []
        request = ua.PublishRequest()
        request.Parameters.SubscriptionAcknowledgements = acks
        self._uasocket.send_request(request, self._call_publish_callback, timeout=int(9e8))  # timeout could be set to 0 but some servers to not support it

    def _call_publish_callback(self, future):
        self.logger.info("call_publish_callback")
        data = future.result()
        self._uasocket.check_answer(data, "ServiceFault received from server while waiting for publish response")
        response = ua.PublishResponse.from_binary(data)
        if response.Parameters.SubscriptionId not in self._publishcallbacks:
            self.logger.warning("Received data for unknown subscription: %s ", response.Parameters.SubscriptionId)
            return
        callback = self._publishcallbacks[response.Parameters.SubscriptionId]
        try:
            callback(response.Parameters)
        except Exception:  # we call client code, catch everything!
            self.logger.exception("Exception while calling user callback: %s")

    def create_monitored_items(self, params):
        self.logger.info("create_monitored_items")
        request = ua.CreateMonitoredItemsRequest()
        request.Parameters = params
        data = self._uasocket.send_request(request)
        response = ua.CreateMonitoredItemsResponse.from_binary(data)
        response.ResponseHeader.ServiceResult.check()
        return response.Results

    def delete_monitored_items(self, params):
        self.logger.info("delete_monitored_items")
        request = ua.DeleteMonitoredItemsRequest()
        request.Parameters = params
        data = self._uasocket.send_request(request)
        response = ua.DeleteMonitoredItemsResponse.from_binary(data)
        response.ResponseHeader.ServiceResult.check()
        return response.Results

    def add_nodes(self, nodestoadd):
        self.logger.info("add_nodes")
        request = ua.AddNodesRequest()
        request.Parameters.NodesToAdd = nodestoadd
        data = self._uasocket.send_request(request)
        response = ua.AddNodesResponse.from_binary(data)
        response.ResponseHeader.ServiceResult.check()
        return response.Results

    def call(self, methodstocall):
        request = ua.CallRequest()
        request.Parameters.MethodsToCall = methodstocall
        data = self._uasocket.send_request(request)
        response = ua.CallResponse.from_binary(data)
        response.ResponseHeader.ServiceResult.check()
        return response.Results

    def history_read(self, params):
        self.logger.info("history_read")
        request = ua.HistoryReadRequest()
        request.Parameters = params
        data = self._uasocket.send_request(request)
        response = ua.HistoryReadResponse.from_binary(data)
        response.ResponseHeader.ServiceResult.check()
        return response.Results