The websocket plugin now extends AsyncRunnablePlugin too

platypush/plugins/websocket/__init__.py

@@ -2,18 +2,20 @@ import asyncio
 import json
 import time
 
-from websockets import connect as websocket_connect
+from typing import Optional, Collection
+
+from websockets import connect as websocket_connect  # type: ignore
 from websockets.exceptions import ConnectionClosed
 
-from platypush.context import get_or_create_event_loop, get_bus
+from platypush.context import get_bus
 from platypush.message.event.websocket import WebsocketMessageEvent
-from platypush.plugins import Plugin, action
+from platypush.plugins import AsyncRunnablePlugin, action
 from platypush.utils import get_ssl_client_context
 
 
-class WebsocketPlugin(Plugin):
+class WebsocketPlugin(AsyncRunnablePlugin):
     """
-    Plugin to send messages over a websocket connection.
+    Plugin to send and receive messages over websocket connections.
 
     Triggers:
 
@@ -22,6 +24,22 @@ class WebsocketPlugin(Plugin):
 
     """
 
+    def __init__(self, subscriptions: Optional[Collection[str]] = None, **kwargs):
+        """
+        :param subscriptions: List of websocket URLs that should be subscribed
+            at startup, prefixed by ``ws://`` or ``wss://``.
+        """
+        super().__init__(**kwargs)
+        self._subscriptions = subscriptions or []
+
+    @property
+    def loop(self):
+        if not self._loop:
+            self._loop = asyncio.new_event_loop()
+            asyncio.set_event_loop(self._loop)
+
+        return self._loop
+
     @action
     def send(
         self,
@@ -52,6 +70,8 @@ class WebsocketPlugin(Plugin):
             otherwise nothing.
         """
 
+        msg = self._parse_msg(msg)
+
         async def send():
             websocket_args = {
                 'ssl': self._get_ssl_context(
@@ -70,13 +90,11 @@ class WebsocketPlugin(Plugin):
                     self.logger.warning('Error on websocket %s: %s', url, err)
 
                 if wait_response:
-                    messages = await self._ws_recv(ws, num_messages=1)
+                    messages = await self._recv(ws, num_messages=1)
                     if messages:
                         return self._parse_msg(messages[0])
 
-        msg = self._parse_msg(msg)
-        loop = get_or_create_event_loop()
-        return loop.run_until_complete(send())
+        return asyncio.run_coroutine_threadsafe(send(), self.loop).result()
 
     @action
     def recv(
@@ -123,14 +141,11 @@ class WebsocketPlugin(Plugin):
             }
 
             async with websocket_connect(url, **websocket_args) as ws:
-                return await self._ws_recv(
-                    ws, timeout=timeout, num_messages=num_messages
-                )
+                return await self._recv(ws, timeout=timeout, num_messages=num_messages)
 
-        loop = get_or_create_event_loop()
-        return loop.run_until_complete(recv())
+        return self.loop.call_soon_threadsafe(recv)
 
-    async def _ws_recv(self, ws, timeout=0, num_messages=0):
+    async def _recv(self, ws, timeout=0, num_messages=0):
         messages = []
         time_start = time.time()
         time_end = time_start + timeout if timeout else 0
@@ -166,6 +181,10 @@ class WebsocketPlugin(Plugin):
 
         return messages
 
+    @property
+    def _should_start_runner(self):
+        return bool(self._subscriptions)
+
     @staticmethod
     def _parse_msg(msg):
         try:
@@ -175,11 +194,18 @@ class WebsocketPlugin(Plugin):
 
         return msg
 
+    async def listen(self):
+        async def _recv(url):
+            async with websocket_connect(url) as ws:
+                return await self._recv(ws)
+
+        await asyncio.wait([_recv(url) for url in set(self._subscriptions)])
+
     @staticmethod
     def _get_ssl_context(
         url: str, ssl_cert=None, ssl_key=None, ssl_cafile=None, ssl_capath=None
     ):
-        if url.startswith('wss://'):
+        if url.startswith('wss://') or url.startswith('https://'):
             return get_ssl_client_context(
                 ssl_cert=ssl_cert,
                 ssl_key=ssl_key,