service/ws.py

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# Copyright 2017 Mycroft AI Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
import json
import sys
import traceback

import tornado.websocket
from pyee import EventEmitter

from mycroft.messagebus.message import Message
from mycroft.util.log import LOG


EventBusEmitter = EventEmitter()

client_connections = []


class WebsocketEventHandler(tornado.websocket.WebSocketHandler):
    def __init__(self, application, request, **kwargs):
        tornado.websocket.WebSocketHandler.__init__(
            self, application, request, **kwargs)
        self.emitter = EventBusEmitter

    def on(self, event_name, handler):
        self.emitter.on(event_name, handler)

    def on_message(self, message):
        # LOG.debug(message)
        try:
            deserialized_message = Message.deserialize(message)
        except Exception:
            return

        try:
            self.emitter.emit(deserialized_message.type, deserialized_message)
        except Exception as e:
            LOG.exception(e)
            traceback.print_exc(file=sys.stdout)
            pass

        for client in client_connections:
            client.write_message(message)

    def open(self):
        self.write_message(Message("connected").serialize())
        client_connections.append(self)

    def on_close(self):
        client_connections.remove(self)

    def emit(self, channel_message):
        if (hasattr(channel_message, 'serialize') and
                callable(getattr(channel_message, 'serialize'))):
            self.write_message(channel_message.serialize())
        else:
            self.write_message(json.dumps(channel_message))

    def check_origin(self, origin):
        return True