Added recv action on websocket plugin

platypush/message/event/websocket.py

@@ -0,0 +1,16 @@
+from typing import Any
+
+from platypush.message.event import Event
+
+
+class WebsocketMessageEvent(Event):
+    """
+    Event triggered when a message is receive on a subscribed websocket URL.
+    """
+
+    def __init__(self, *args, url: str, message: Any, **kwargs):
+        """
+        :param url: Websocket URL.
+        :param message: The received message.
+        """
+        super().__init__(*args, url=url, message=message, **kwargs)

platypush/plugins/websocket/__init__.py

@@ -1,13 +1,12 @@
+import asyncio
 import json
+import time
 
-try:
-    from websockets.exceptions import ConnectionClosed
 from websockets import connect as websocket_connect
-except ImportError:
+from websockets.exceptions import ConnectionClosed
-    from websockets import ConnectionClosed, connect as websocket_connect
 
-from platypush.context import get_or_create_event_loop
+from platypush.context import get_or_create_event_loop, get_bus
-from platypush.message import Message
+from platypush.message.event.websocket import WebsocketMessageEvent
 from platypush.plugins import Plugin, action
 from platypush.utils import get_ssl_client_context
 
@@ -15,61 +14,180 @@ from platypush.utils import get_ssl_client_context
 class WebsocketPlugin(Plugin):
     """
     Plugin to send messages over a websocket connection.
+
+    Triggers:
+
+        * :class:`platypush.message.event.websocket.WebsocketMessageEvent` when
+            a message is received on a subscribed websocket.
+
     """
 
-    def __init__(self, **kwargs):
-        super().__init__(**kwargs)
-
     @action
-    def send(self, url, msg, ssl_cert=None, ssl_key=None, ssl_cafile=None, ssl_capath=None):
+    def send(
+        self,
+        url: str,
+        msg,
+        ssl_cert=None,
+        ssl_key=None,
+        ssl_cafile=None,
+        ssl_capath=None,
+        wait_response=False,
+    ):
         """
         Sends a message to a websocket.
 
         :param url: Websocket URL, e.g. ws://localhost:8765 or wss://localhost:8765
-        :type url: 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
-        :param ssl_cert: Path to the SSL certificate to be used, if the SSL connection requires client authentication
+            connection requires client authentication as well (default: None)
-            as well (default: None) :type ssl_cert: str
+        :param ssl_key: Path to the SSL key to be used, if the SSL connection
-
+            requires client authentication as well (default: None)
-        :param ssl_key: Path to the SSL key to be used, if the SSL connection requires client authentication as well
+        :param ssl_cafile: Path to the certificate authority file if required
-            (default: None) :type ssl_key: str
+            by the SSL configuration (default: None)
-
+        :param ssl_capath: Path to the certificate authority directory if
-        :param ssl_cafile: Path to the certificate authority file if required by the SSL configuration (default: None)
+            required by the SSL configuration (default: None)
-        :type ssl_cafile: str
+        :param wait_response: Set to True if you expect a response to the
-
+            delivered message.
-        :param ssl_capath: Path to the certificate authority directory if required by the SSL configuration
+        :return: The received response if ``wait_response`` is set to True,
-            (default: None)
+            otherwise nothing.
-        :type ssl_capath: str
         """
 
         async def send():
-            websocket_args = {}
+            websocket_args = {
-            if ssl_cert:
+                'ssl': self._get_ssl_context(
-                websocket_args['ssl'] = get_ssl_client_context(ssl_cert=ssl_cert,
+                    url,
+                    ssl_cert=ssl_cert,
                     ssl_key=ssl_key,
                     ssl_cafile=ssl_cafile,
-                                                               ssl_capath=ssl_capath)
+                    ssl_capath=ssl_capath,
+                )
+            }
 
-            async with websocket_connect(url, **websocket_args) as websocket:
+            async with websocket_connect(url, **websocket_args) as ws:
                 try:
-                    await websocket.send(str(msg))
+                    await ws.send(str(msg))
                 except ConnectionClosed as err:
-                    self.logger.warning('Error on websocket {}: {}'.
+                    self.logger.warning('Error on websocket %s: %s', url, err)
-                                        format(url, err))
 
-        try:
+                if wait_response:
-            msg = json.dumps(msg)
+                    messages = await self._ws_recv(ws, num_messages=1)
-        except Exception as e:
+                    if messages:
-            self.logger.debug(e)
+                        return self._parse_msg(messages[0])
 
-        try:
+        msg = self._parse_msg(msg)
-            msg = Message.build(json.loads(msg))
+        loop = get_or_create_event_loop()
-        except Exception as e:
+        return loop.run_until_complete(send())
-            self.logger.debug(e)
+
+    @action
+    def recv(
+        self,
+        url: str,
+        ssl_cert=None,
+        ssl_key=None,
+        ssl_cafile=None,
+        ssl_capath=None,
+        num_messages=0,
+        timeout=0,
+    ):
+        """
+        Receive one or more messages from a websocket.
+
+        A :class:`platypush.message.event.websocket.WebsocketMessageEvent`
+        event will be triggered whenever a new message is received.
+
+        :param url: Websocket URL, e.g. ws://localhost:8765 or wss://localhost:8765
+        :param ssl_cert: Path to the SSL certificate to be used, if the SSL
+            connection requires client authentication as well (default: None)
+        :param ssl_key: Path to the SSL key to be used, if the SSL connection
+            requires client authentication as well (default: None)
+        :param ssl_cafile: Path to the certificate authority file if required
+            by the SSL configuration (default: None)
+        :param ssl_capath: Path to the certificate authority directory if
+            required by the SSL configuration (default: None)
+        :param num_messages: Exit after receiving this number of messages.
+            Default: 0, receive forever.
+        :param timeout: Message receive timeout in seconds. Default: 0 - no timeout.
+        :return: A list with the messages that have been received, unless
+            ``num_messages`` is set to 0 or ``None``.
+        """
+
+        async def recv():
+            websocket_args = {
+                'ssl': self._get_ssl_context(
+                    url,
+                    ssl_cert=ssl_cert,
+                    ssl_key=ssl_key,
+                    ssl_cafile=ssl_cafile,
+                    ssl_capath=ssl_capath,
+                )
+            }
+
+            async with websocket_connect(url, **websocket_args) as ws:
+                return await self._ws_recv(
+                    ws, timeout=timeout, num_messages=num_messages
+                )
 
         loop = get_or_create_event_loop()
-        loop.run_until_complete(send())
+        return loop.run_until_complete(recv())
+
+    async def _ws_recv(self, ws, timeout=0, num_messages=0):
+        messages = []
+        time_start = time.time()
+        time_end = time_start + timeout if timeout else 0
+        url = 'ws{secure}://{host}:{port}{path}'.format(
+            secure='s' if ws.secure else '',
+            host=ws.host,
+            port=ws.port,
+            path=ws.path,
+        )
+
+        while (not num_messages) or (len(messages) < num_messages):
+            msg = None
+            err = None
+            remaining_timeout = time_end - time.time() if time_end else None
+
+            try:
+                msg = await asyncio.wait_for(ws.recv(), remaining_timeout)
+            except (ConnectionClosed, asyncio.exceptions.TimeoutError) as e:
+                err = e
+                self.logger.warning('Error on websocket %s: %s', url, e)
+
+            if isinstance(err, ConnectionClosed) or (
+                time_end and time.time() > time_end
+            ):
+                break
+
+            if msg is None:
+                continue
+
+            msg = self._parse_msg(msg)
+            messages.append(msg)
+            get_bus().post(WebsocketMessageEvent(url=url, message=msg))
+
+        return messages
+
+    @staticmethod
+    def _parse_msg(msg):
+        try:
+            msg = json.dumps(msg)
+        except Exception:
+            pass
+
+        return msg
+
+    @staticmethod
+    def _get_ssl_context(
+        url: str, ssl_cert=None, ssl_key=None, ssl_cafile=None, ssl_capath=None
+    ):
+        if url.startswith('wss://'):
+            return get_ssl_client_context(
+                ssl_cert=ssl_cert,
+                ssl_key=ssl_key,
+                ssl_cafile=ssl_cafile,
+                ssl_capath=ssl_capath,
+            )
+
+        return None
+
 
 # vim:sw=4:ts=4:et:

platypush/plugins/websocket/manifest.yaml

@@ -1,5 +1,7 @@
 manifest:
-  events: {}
+  events:
+    platypush.message.event.websocket.WebsocketMessageEvent: when a message is
+      received on a subscribed websocket.
   install:
     pip: []
   package: platypush.plugins.websocket