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from __future__ import absolute_import

import traceback

from autobahn.websocket import protocol
from autobahn.websocket.types import ConnectionDeny
from autobahn.wamp.interfaces import ITransport
from autobahn.wamp.exception import ProtocolError, SerializationError, TransportLost

__all__ = ('WampWebSocketServerProtocol',
           'WampWebSocketClientProtocol',
           'WampWebSocketServerFactory',
           'WampWebSocketClientFactory')


class WampWebSocketProtocol(object):
    """
    Base class for WAMP-over-WebSocket transport mixins.
    """

    _session = None  # default; self.session is set in onOpen

    def _bailout(self, code, reason=None):
        self.log.debug('Failing WAMP-over-WebSocket transport: code={code}, reason="{reason}"', code=code, reason=reason)
        self._fail_connection(code, reason)

    def onOpen(self):
        """
        Callback from :func:`autobahn.websocket.interfaces.IWebSocketChannel.onOpen`
        """
        # WebSocket connection established. Now let the user WAMP session factory
        # create a new WAMP session and fire off session open callback.
        try:
            self._session = self.factory._factory()
            self._session.onOpen(self)
        except Exception as e:
            self.log.critical("{tb}", tb=traceback.format_exc())
            reason = u'WAMP Internal Error ({0})'.format(e)
            self._bailout(protocol.WebSocketProtocol.CLOSE_STATUS_CODE_INTERNAL_ERROR, reason=reason)

    def onClose(self, wasClean, code, reason):
        """
        Callback from :func:`autobahn.websocket.interfaces.IWebSocketChannel.onClose`
        """
        # WAMP session might never have been established in the first place .. guard this!
        if self._session is not None:
            # WebSocket connection lost - fire off the WAMP
            # session close callback
            # noinspection PyBroadException
            try:
                self.log.debug('WAMP-over-WebSocket transport lost: wasClean={wasClean}, code={code}, reason="{reason}"', wasClean=wasClean, code=code, reason=reason)
                self._session.onClose(wasClean)
            except Exception:
                self.log.critical("{tb}", tb=traceback.format_exc())
            self._session = None

    def onMessage(self, payload, isBinary):
        """
        Callback from :func:`autobahn.websocket.interfaces.IWebSocketChannel.onMessage`
        """
        try:
            for msg in self._serializer.unserialize(payload, isBinary):
                self.log.trace(
                    "WAMP RECV: message={message}, session={session}, authid={authid}",
                    authid=self._session._authid,
                    session=self._session._session_id,
                    message=msg,
                )
                self._session.onMessage(msg)

        except ProtocolError as e:
            self.log.critical("{tb}", tb=traceback.format_exc())
            reason = u'WAMP Protocol Error ({0})'.format(e)
            self._bailout(protocol.WebSocketProtocol.CLOSE_STATUS_CODE_PROTOCOL_ERROR, reason=reason)

        except Exception as e:
            self.log.critical("{tb}", tb=traceback.format_exc())
            reason = u'WAMP Internal Error ({0})'.format(e)
            self._bailout(protocol.WebSocketProtocol.CLOSE_STATUS_CODE_INTERNAL_ERROR, reason=reason)

    def send(self, msg):
        """
        Implements :func:`autobahn.wamp.interfaces.ITransport.send`
        """
        if self.isOpen():
            try:
                self.log.trace(
                    "WAMP SEND: message={message}, session={session}, authid={authid}",
                    authid=self._session._authid,
                    session=self._session._session_id,
                    message=msg,
                )
                payload, isBinary = self._serializer.serialize(msg)
            except Exception as e:
                self.log.error("WAMP message serialization error: {}".format(e))
                # all exceptions raised from above should be serialization errors ..
                raise SerializationError(u"WAMP message serialization error: {0}".format(e))
            else:
                self.sendMessage(payload, isBinary)
        else:
            raise TransportLost()

    def isOpen(self):
        """
        Implements :func:`autobahn.wamp.interfaces.ITransport.isOpen`
        """
        return self._session is not None

    def close(self):
        """
        Implements :func:`autobahn.wamp.interfaces.ITransport.close`
        """
        if self.isOpen():
            self.sendClose(protocol.WebSocketProtocol.CLOSE_STATUS_CODE_NORMAL)
        else:
            raise TransportLost()

    def abort(self):
        """
        Implements :func:`autobahn.wamp.interfaces.ITransport.abort`
        """
        if self.isOpen():
            self._bailout(protocol.WebSocketProtocol.CLOSE_STATUS_CODE_GOING_AWAY)
        else:
            raise TransportLost()


ITransport.register(WampWebSocketProtocol)


def parseSubprotocolIdentifier(subprotocol):
    try:
        s = subprotocol.split(u'.')
        if s[0] != u'wamp':
            raise Exception(u'WAMP WebSocket subprotocol identifier must start with "wamp", not "{}"'.format(s[0]))
        version = int(s[1])
        serializerId = u'.'.join(s[2:])
        return version, serializerId
    except:
        return None, None


class WampWebSocketServerProtocol(WampWebSocketProtocol):
    """
    Mixin for WAMP-over-WebSocket server transports.
    """

    STRICT_PROTOCOL_NEGOTIATION = True

    def onConnect(self, request):
        """
        Callback from :func:`autobahn.websocket.interfaces.IWebSocketChannel.onConnect`
        """
        headers = {}
        for subprotocol in request.protocols:
            version, serializerId = parseSubprotocolIdentifier(subprotocol)
            if version == 2 and serializerId in self.factory._serializers.keys():
                self._serializer = self.factory._serializers[serializerId]
                return subprotocol, headers

        if self.STRICT_PROTOCOL_NEGOTIATION:
            raise ConnectionDeny(ConnectionDeny.BAD_REQUEST, u'This server only speaks WebSocket subprotocols {}'.format(u', '.join(self.factory.protocols)))
        else:
            # assume wamp.2.json
            self._serializer = self.factory._serializers[u'json']
            return None, headers


class WampWebSocketClientProtocol(WampWebSocketProtocol):
    """
    Mixin for WAMP-over-WebSocket client transports.
    """

    STRICT_PROTOCOL_NEGOTIATION = True

    def onConnect(self, response):
        """
        Callback from :func:`autobahn.websocket.interfaces.IWebSocketChannel.onConnect`
        """
        if response.protocol not in self.factory.protocols:
            if self.STRICT_PROTOCOL_NEGOTIATION:
                raise Exception(u'The server does not speak any of the WebSocket subprotocols {} we requested.'.format(u', '.join(self.factory.protocols)))
            else:
                # assume wamp.2.json
                serializerId = u'json'
        else:
            version, serializerId = parseSubprotocolIdentifier(response.protocol)

        self._serializer = self.factory._serializers[serializerId]


class WampWebSocketFactory(object):
    """
    Base class for WAMP-over-WebSocket transport factory mixins.
    """

    def __init__(self, factory, serializers=None):
        """
        Ctor.

        :param factory: A callable that produces instances that implement
           :class:`autobahn.wamp.interfaces.ITransportHandler`
        :type factory: callable
        :param serializers: A list of WAMP serializers to use (or None for default
           serializers). Serializers must implement
           :class:`autobahn.wamp.interfaces.ISerializer`.
        :type serializers: list
        """
        if callable(factory):
            self._factory = factory
        else:
            self._factory = lambda: factory

        if serializers is None:
            serializers = []

            # try CBOR WAMP serializer
            try:
                from autobahn.wamp.serializer import CBORSerializer
                serializers.append(CBORSerializer(batched=True))
                serializers.append(CBORSerializer())
            except ImportError:
                pass

            # try MsgPack WAMP serializer
            try:
                from autobahn.wamp.serializer import MsgPackSerializer
                serializers.append(MsgPackSerializer(batched=True))
                serializers.append(MsgPackSerializer())
            except ImportError:
                pass

            # try UBJSON WAMP serializer
            try:
                from autobahn.wamp.serializer import UBJSONSerializer
                serializers.append(UBJSONSerializer(batched=True))
                serializers.append(UBJSONSerializer())
            except ImportError:
                pass

            # try JSON WAMP serializer
            try:
                from autobahn.wamp.serializer import JsonSerializer
                serializers.append(JsonSerializer(batched=True))
                serializers.append(JsonSerializer())
            except ImportError:
                pass

            if not serializers:
                raise Exception(u'Could not import any WAMP serializer')

        self._serializers = {}
        for ser in serializers:
            self._serializers[ser.SERIALIZER_ID] = ser

        self._protocols = [u'wamp.2.{}'.format(ser.SERIALIZER_ID) for ser in serializers]


class WampWebSocketServerFactory(WampWebSocketFactory):
    """
    Mixin for WAMP-over-WebSocket server transport factories.
    """


class WampWebSocketClientFactory(WampWebSocketFactory):
    """
    Mixin for WAMP-over-WebSocket client transport factories.
    """
