opcua.UASocketClient

Complexity

Total Complexity

33

Size/Duplication

Total Lines	187
Duplicated Lines	0 %

Test Coverage

Coverage

91.91%

15 Methods

Rating	Name	Duplication	Size	Complexity
A	send_request()	0	11	2
A	check_answer()	0	9	2
A	__init__()	0	15	1
A	open_secure_channel()	0	10	1
A	_create_request_header()	0	7	1
A	_write_socket()	0	12	2
A	connect_socket()	0	9	1
A	send_hello()	0	11	2
A	start()	0	8	1
B	_send_request()	0	29	5
B	_receive()	0	15	6
A	close_secure_channel()	0	13	2
A	disconnect_socket()	0	4	1
A	_run()	0	9	3
A	_call_callback()	0	6	3

"""
Low level binary client
"""

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

import opcua.uaprotocol as ua
import opcua.utils as 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._security_token = ua.ChannelSecurityToken()
        self.authentication_token = ua.NodeId()
        self._sequence_number = 0
        self._request_id = 0
        self._request_handle = 0
        self._callbackmap = {}
        self._security_policy = security_policy
        self._max_chunk_size = 65536

    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
            for chunk in ua.MessageChunk.message_to_chunks(self._security_policy, binreq, self._max_chunk_size,
                    message_type=message_type,
                    channel_id=self._security_token.ChannelId,
                    request_id=self._request_id,
                    token_id=self._security_token.TokenId):
                self._sequence_number += 1
                chunk.SequenceHeader.SequenceNumber = self._sequence_number
                self._socket.write(chunk.to_binary())
        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(50)  # FIXME check max length nodeid + responseheader
        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 = ua.tcp_message_from_socket(self._security_policy, self._socket)
        if isinstance(msg, ua.MessageChunk):
            chunks = [msg]
            # TODO: check everything
            while chunks[-1].MessageHeader.ChunkType == ua.ChunkType.Intermediate:
                chunks.append(ua.tcp_message_from_socket(self._security_policy, self._socket))
            body = b"".join([c.Body for c in chunks])
            self._call_callback(msg.SequenceHeader.RequestId, utils.Buffer(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 _write_socket(self, hdr, *args):
        alle = []
        for arg in args:
            data = arg.to_binary()
            hdr.add_size(len(data))
            self.logger.debug("writting to socket: %s with length %s ", type(arg), len(data))
            self.logger.debug("struct: %s", arg)
            self.logger.debug("data: %s", data)
            alle.append(data)
        alle.insert(0, hdr.to_binary())
        alle = b"".join(alle)
        self._socket.write(alle)

    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
        header = ua.Header(ua.MessageType.Hello, ua.ChunkType.Single)
        future = Future()
        with self._lock:
            self._callbackmap[0] = future
        self._write_socket(header, hello)
        ack = future.result(self.timeout)
        self._max_chunk_size = ack.SendBufferSize	# client shouldn't send chunks larger than this
        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._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, security_policy=ua.SecurityPolicy()):
        self.logger = logging.getLogger(__name__)
        self._publishcallbacks = {}
        self._lock = Lock()
        self._timeout = timeout
        self._uasocket = None
        self._security_policy = security_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()
        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
        data = self._uasocket.send_request(request)
        response = ua.CreateSubscriptionResponse.from_binary(data)
        response.ResponseHeader.ServiceResult.check()
        with self._lock:
            self._publishcallbacks[response.Parameters.SubscriptionId] = callback
        return response.Parameters

    def delete_subscriptions(self, subscriptionids):
        self.logger.info("delete_subscription")
        request = ua.DeleteSubscriptionsRequest()
        request.Parameters.SubscriptionIds = subscriptionids
        data = self._uasocket.send_request(request)
        response = ua.DeleteSubscriptionsResponse.from_binary(data)
        response.ResponseHeader.ServiceResult.check()
        for sid in subscriptionids:
            with self._lock:
                self._publishcallbacks.pop(sid)
        return 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)
        with self._lock:
            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