client/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 time
from threading import Event
import traceback

from .threaded_event_emitter import ThreadedEventEmitter
from websocket import (WebSocketApp, WebSocketConnectionClosedException,
                       WebSocketException)

from mycroft.configuration import Configuration
from mycroft.messagebus.message import Message
from mycroft.util import validate_param, create_echo_function
from mycroft.util.log import LOG


class WebsocketClient:
    def __init__(self, host=None, port=None, route=None, ssl=None):

        config = Configuration.get().get("websocket")
        host = host or config.get("host")
        port = port or config.get("port")
        route = route or config.get("route")
        ssl = ssl or config.get("ssl")
        validate_param(host, "websocket.host")
        validate_param(port, "websocket.port")
        validate_param(route, "websocket.route")

        self.url = WebsocketClient.build_url(host, port, route, ssl)
        self.emitter = ThreadedEventEmitter()
        self.client = self.create_client()
        self.retry = 5
        self.connected_event = Event()
        self.started_running = False

    @staticmethod
    def build_url(host, port, route, ssl):
        scheme = "wss" if ssl else "ws"
        return scheme + "://" + host + ":" + str(port) + route

    def create_client(self):
        return WebSocketApp(self.url,
                            on_open=self.on_open, on_close=self.on_close,
                            on_error=self.on_error, on_message=self.on_message)

    def on_open(self):
        LOG.info("Connected")
        self.connected_event.set()
        self.emitter.emit("open")
        # Restore reconnect timer to 5 seconds on sucessful connect
        self.retry = 5

    def on_close(self):
        self.emitter.emit("close")

    def on_error(self, error):
        """ On error start trying to reconnect to the websocket. """
        if isinstance(error, WebSocketConnectionClosedException):
            LOG.warning('Could not send message because connection has closed')
        else:
            LOG.exception('=== ' + repr(error) + ' ===')

        try:
            self.emitter.emit('error', error)
            if self.client.keep_running:
                self.client.close()
        except Exception as e:
            LOG.error('Exception closing websocket: ' + repr(e))

        LOG.warning("WS Client will reconnect in %d seconds." % self.retry)
        time.sleep(self.retry)
        self.retry = min(self.retry * 2, 60)
        try:
            self.emitter.emit('reconnecting')
            self.client = self.create_client()
            self.run_forever()
        except WebSocketException:
            pass

    def on_message(self, message):
        parsed_message = Message.deserialize(message)
        self.emitter.emit('message', message)
        self.emitter.emit(parsed_message.type, parsed_message)

    def emit(self, message):
        if not self.connected_event.wait(10):
            if not self.started_running:
                raise ValueError('You must execute run_forever() '
                                 'before emitting messages')
            self.connected_event.wait()

        try:
            if hasattr(message, 'serialize'):
                self.client.send(message.serialize())
            else:
                self.client.send(json.dumps(message.__dict__))
        except WebSocketConnectionClosedException:
            LOG.warning('Could not send {} message because connection '
                        'has been closed'.format(message.type))

    def wait_for_response(self, message, reply_type=None, timeout=None):
        """Send a message and wait for a response.

        Args:
            message (Message): message to send
            reply_type (str): the message type of the expected reply.
                              Defaults to "<message.type>.response".
            timeout: seconds to wait before timeout, defaults to 3
        Returns:
            The received message or None if the response timed out
        """
        response = []

        def handler(message):
            """Receive response data."""
            response.append(message)

        # Setup response handler
        self.once(reply_type or message.type + '.response', handler)
        # Send request
        self.emit(message)
        # Wait for response
        start_time = time.monotonic()
        while len(response) == 0:
            time.sleep(0.2)
            if time.monotonic() - start_time > (timeout or 3.0):
                try:
                    self.remove(reply_type, handler)
                except (ValueError, KeyError):
                    # ValueError occurs on pyee 1.0.1 removing handlers
                    # registered with once.
                    # KeyError may theoretically occur if the event occurs as
                    # the handler is removed
                    pass
                return None
        return response[0]

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

    def once(self, event_name, func):
        self.emitter.once(event_name, func)

    def remove(self, event_name, func):
        try:
            if event_name in self.emitter._events:
                LOG.debug("Removing found '"+str(event_name)+"'")
            else:
                LOG.debug("Not able to find '"+str(event_name)+"'")
            self.emitter.remove_listener(event_name, func)
        except ValueError:
            LOG.warning('Failed to remove event {}: {}'.format(event_name,
                                                               str(func)))
            for line in traceback.format_stack():
                LOG.warning(line.strip())

            if event_name in self.emitter._events:
                LOG.debug("Removing found '"+str(event_name)+"'")
            else:
                LOG.debug("Not able to find '"+str(event_name)+"'")
            LOG.warning("Existing events: " + str(self.emitter._events))
            for evt in self.emitter._events:
                LOG.warning("   "+str(evt))
                LOG.warning("       "+str(self.emitter._events[evt]))
            if event_name in self.emitter._events:
                LOG.debug("Removing found '"+str(event_name)+"'")
            else:
                LOG.debug("Not able to find '"+str(event_name)+"'")
            LOG.warning('----- End dump -----')

    def remove_all_listeners(self, event_name):
        '''
            Remove all listeners connected to event_name.

            Args:
                event_name: event from which to remove listeners
        '''
        if event_name is None:
            raise ValueError
        self.emitter.remove_all_listeners(event_name)

    def run_forever(self):
        self.started_running = True
        self.client.run_forever()

    def close(self):
        self.client.close()
        self.connected_event.clear()


def echo():
    ws = WebsocketClient()

    def repeat_utterance(message):
        message.type = 'speak'
        ws.emit(message)

    ws.on('message', create_echo_function(None))
    ws.on('recognizer_loop:utterance', repeat_utterance)
    ws.run_forever()


if __name__ == "__main__":
    echo()