Added websocket backend and plugin

This commit is contained in:
Fabio Manganiello 2018-10-26 21:55:49 +02:00
parent 8635ed8268
commit 92a3759721
4 changed files with 181 additions and 4 deletions

View file

@ -15,7 +15,7 @@ from flask import Flask, Response, abort, jsonify, request as http_request, \
from redis import Redis
from platypush.config import Config
from platypush.context import get_backend
from platypush.context import get_backend, get_or_create_event_loop
from platypush.message import Message
from platypush.message.event import Event, StopEvent
from platypush.message.event.web.widget import WidgetUpdateEvent
@ -146,7 +146,7 @@ class HttpBackend(Backend):
except Exception as e:
self.logger.warning('Error on websocket send_event: {}'.format(e))
loop = asyncio.new_event_loop()
loop = get_or_create_event_loop()
for websocket in self.active_websockets:
try:
@ -370,8 +370,7 @@ class HttpBackend(Backend):
self.logger.info('Websocket client {} closed connection'.format(websocket.remote_address[0]))
self.active_websockets.remove(websocket)
loop = asyncio.new_event_loop()
asyncio.set_event_loop(loop)
loop = get_or_create_event_loop()
loop.run_until_complete(
websockets.serve(register_websocket, '0.0.0.0', self.websocket_port))
loop.run_forever()

View file

@ -0,0 +1,105 @@
import asyncio
import os
import ssl
import threading
import websockets
from platypush.backend import Backend
from platypush.context import get_plugin, get_or_create_event_loop
from platypush.message import Message
from platypush.message.request import Request
class WebsocketBackend(Backend):
"""
Backend to communicate messages over a websocket medium.
Requires:
* **websockets** (``pip install websockets``)
"""
def __init__(self, port=8765, bind_address='0.0.0.0', ssl_cert=None, **kwargs):
"""
:param port: Listen port for the websocket server (default: 8765)
:type port: int
:param bind_address: Bind address for the websocket server (default: 0.0.0.0, listen for any IP connection)
:type websocket_port: str
:param ssl_cert: Path to the PEM certificate file if you want to enable SSL (default: None)
:type ssl_cert: str
"""
super().__init__(**kwargs)
self.port = port
self.bind_address = bind_address
self.ssl_context = None
if ssl_cert:
self.ssl_context = ssl.SSLContext(ssl.PROTOCOL_TLS_SERVER)
self.ssl_context.load_cert_chain(os.path.abspath(
os.path.expanduser(ssl_cert)))
def send_message(self, msg):
websocket = get_plugin('websocket')
websocket_args = {}
if self.ssl_context:
url = 'wss://localhost:{}'.format(self.port)
websocket_args['ssl'] = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)
websocket_args['ssl'].load_cert_chain(os.path.abspath(
os.path.expanduser(ssl_cert)))
else:
url = 'ws://localhost:{}'.format(self.port)
websocket.send(url=url, msg=msg, **websocket_args)
def run(self):
super().run()
async def serve_client(websocket, path):
self.logger.info('New websocket connection from {}'.
format(websocket.remote_address[0]))
try:
msg = await websocket.recv()
msg = Message.build(msg)
self.logger.info('Received message from {}: {}'.
format(websocket.remote_address[0], msg))
self.on_message(msg)
if isinstance(msg, Request):
response = self.get_message_response(msg)
if response:
self.logger.info('Processing response on the websocket backend: {}'.
format(response))
await websocket.send(str(response))
except Exception as e:
if isinstance(e, websockets.exceptions.ConnectionClosed):
self.logger.info('Websocket client {} closed connection'.
format(websocket.remote_address[0]))
else:
self.logger.exception(e)
self.logger.info('Initialized websocket backend on port {}, bind address: {}'.
format(self.port, self.bind_address))
websocket_args = {}
if self.ssl_context:
websocket_args['ssl'] = self.ssl_context
loop = get_or_create_event_loop()
server = websockets.serve(serve_client, self.bind_address, self.port, **websocket_args)
loop.run_until_complete(server)
loop.run_forever()
# vim:sw=4:ts=4:et:

View file

@ -1,3 +1,4 @@
import asyncio
import importlib
import logging
@ -113,5 +114,15 @@ def register_plugin(name, plugin, **kwargs):
""" Registers a plugin instance by name """
global plugins
def get_or_create_event_loop():
try:
loop = asyncio.get_event_loop()
except RuntimeError:
loop = asyncio.new_event_loop()
asyncio.set_event_loop(loop)
return loop
# vim:sw=4:ts=4:et:

View file

@ -0,0 +1,62 @@
import asyncio
import json
import os
import websockets
from platypush.context import get_or_create_event_loop
from platypush.message import Message
from platypush.plugins import Plugin, action
class WebsocketPlugin(Plugin):
"""
Plugin to send messages over a websocket connection
Requires:
* **websockets** (``pip install websockets``)
"""
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
@action
def send(self, url, msg, ssl_cert=None, *args, **kwargs):
"""
Sends a message to a websocket.
:param url: Websocket URL, e.g. ws://localhost:8765 or wss://localhost:8765
:type topic: str
:param msg: Message to be sent. It can be a list, a dict, or a Message object
:param ssl_cert: Path to the SSL certificate to be used, if the SSL connection requires client authentication as well (default: None)
:type ssl_cert: str
"""
async def send():
websocket_args = {}
if ssl_cert:
ssl_context = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)
ssl_context.load_cert_chain(os.path.abspath(
os.path.expanduser(ssl_cert)))
async with websockets.connect(url, **websocket_args) as websocket:
try:
await websocket.send(str(msg))
except websockets.exceptions.ConnectionClosed:
self.logger.warning('Error on websocket {}: {}'.
format(url, e))
try: msg = json.dumps(msg)
except: pass
try: msg = Message.build(json.loads(msg))
except: pass
loop = get_or_create_event_loop()
loop.run_until_complete(send())
# vim:sw=4:ts=4:et: