165 lines
6.1 KiB
Python
165 lines
6.1 KiB
Python
from platypush.backend import Backend
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try:
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from websockets.exceptions import ConnectionClosed
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from websockets import serve as websocket_serve
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except ImportError:
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from websockets import ConnectionClosed, serve as websocket_serve
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from platypush.context import get_plugin, get_or_create_event_loop
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from platypush.message import Message
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from platypush.message.request import Request
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from platypush.message.response import Response
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from platypush.utils import get_ssl_server_context
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class WebsocketBackend(Backend):
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"""
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Backend to communicate messages over a websocket medium.
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"""
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# Websocket client message recv timeout in seconds
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_websocket_client_timeout = 0
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# Default websocket service port
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_default_websocket_port = 8765
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def __init__(self, port=_default_websocket_port, bind_address='0.0.0.0',
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ssl_cafile=None, ssl_capath=None, ssl_cert=None, ssl_key=None,
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client_timeout=_websocket_client_timeout, **kwargs):
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"""
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:param port: Listen port for the websocket server (default: 8765)
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:type port: int
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:param bind_address: Bind address for the websocket server (default: 0.0.0.0, listen for any IP connection)
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:type websocket_port: str
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:param ssl_cert: Path to the certificate file if you want to enable SSL (default: None)
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:type ssl_cert: str
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:param ssl_key: Path to the key file if you want to enable SSL (default: None)
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:type ssl_key: str
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:param ssl_cafile: Path to the certificate authority file if required by the SSL configuration (default: None)
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:type ssl_cafile: str
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:param ssl_capath: Path to the certificate authority directory if required by the SSL configuration
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(default: None)
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:type ssl_capath: str
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:param client_timeout: Timeout without any messages being received before closing a client connection.
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A zero timeout keeps the websocket open until an error occurs (default: 0, no timeout)
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:type ping_timeout: int
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"""
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super().__init__(**kwargs)
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self.port = port
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self.bind_address = bind_address
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self.client_timeout = client_timeout
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self.active_websockets = set()
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self._loop = None
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self.ssl_context = get_ssl_server_context(ssl_cert=ssl_cert,
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ssl_key=ssl_key,
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ssl_cafile=ssl_cafile,
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ssl_capath=ssl_capath) \
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if ssl_cert else None
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def send_message(self, msg, **kwargs):
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websocket = get_plugin('websocket')
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websocket_args = {}
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if self.ssl_context:
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url = 'wss://localhost:{}'.format(self.port)
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websocket_args['ssl'] = self.ssl_context
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else:
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url = 'ws://localhost:{}'.format(self.port)
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websocket.send(url=url, msg=msg, **websocket_args)
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def notify_web_clients(self, event):
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""" Notify all the connected web clients (over websocket) of a new event """
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async def send_event(websocket):
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try:
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await websocket.send(str(event))
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except Exception as e:
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self.logger.warning('Error on websocket send_event: {}'.format(e))
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loop = get_or_create_event_loop()
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active_websockets = self.active_websockets.copy()
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for ws in active_websockets:
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try:
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loop.run_until_complete(send_event(ws))
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except ConnectionClosed:
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self.logger.info('Client connection lost')
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self.active_websockets.remove(ws)
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def run(self):
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import asyncio
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super().run()
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self.register_service(port=self.port, name='ws')
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# noinspection PyUnusedLocal
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async def serve_client(websocket, path):
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self.active_websockets.add(websocket)
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self.logger.debug('New websocket connection from {}'.
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format(websocket.remote_address[0]))
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try:
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while not self.should_stop():
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if self.client_timeout:
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msg = await asyncio.wait_for(websocket.recv(),
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timeout=self.client_timeout)
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else:
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msg = await websocket.recv()
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msg = Message.build(msg)
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self.logger.info('Received message from {}: {}'.
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format(websocket.remote_address[0], msg))
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self.on_message(msg)
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if isinstance(msg, Request):
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response = self.get_message_response(msg) or Response()
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self.logger.info('Processing response on the websocket backend: {}'.
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format(response))
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await websocket.send(str(response))
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except ConnectionClosed as e:
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self.active_websockets.remove(websocket)
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self.logger.debug('Websocket client {} closed connection'.
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format(websocket.remote_address[0]))
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except asyncio.TimeoutError as e:
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self.active_websockets.remove(websocket)
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self.logger.debug('Websocket connection to {} timed out'.
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format(websocket.remote_address[0]))
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except Exception as e:
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self.logger.exception(e)
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self.logger.info('Initialized websocket backend on port {}, bind address: {}'.
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format(self.port, self.bind_address))
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websocket_args = {}
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if self.ssl_context:
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websocket_args['ssl'] = self.ssl_context
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self._loop = get_or_create_event_loop()
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server = websocket_serve(serve_client, self.bind_address, self.port, **websocket_args)
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self._loop.run_until_complete(server)
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self._loop.run_forever()
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def on_stop(self):
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self.logger.info('Received STOP event on the websocket backend')
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if self._loop:
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self._loop.stop()
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self.logger.info('Websocket backend terminated')
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# vim:sw=4:ts=4:et:
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