181 lines
7.4 KiB
Python
181 lines
7.4 KiB
Python
from functools import partial
|
|
import uuid
|
|
|
|
from engineio import json
|
|
import pickle
|
|
|
|
from .base_manager import BaseManager
|
|
|
|
|
|
class PubSubManager(BaseManager):
|
|
"""Manage a client list attached to a pub/sub backend.
|
|
|
|
This is a base class that enables multiple servers to share the list of
|
|
clients, with the servers communicating events through a pub/sub backend.
|
|
The use of a pub/sub backend also allows any client connected to the
|
|
backend to emit events addressed to Socket.IO clients.
|
|
|
|
The actual backends must be implemented by subclasses, this class only
|
|
provides a pub/sub generic framework.
|
|
|
|
:param channel: The channel name on which the server sends and receives
|
|
notifications.
|
|
"""
|
|
name = 'pubsub'
|
|
|
|
def __init__(self, channel='socketio', write_only=False, logger=None):
|
|
super(PubSubManager, self).__init__()
|
|
self.channel = channel
|
|
self.write_only = write_only
|
|
self.host_id = uuid.uuid4().hex
|
|
self.logger = logger
|
|
|
|
def initialize(self):
|
|
super(PubSubManager, self).initialize()
|
|
if not self.write_only:
|
|
self.thread = self.server.start_background_task(self._thread)
|
|
self._get_logger().info(self.name + ' backend initialized.')
|
|
|
|
def emit(self, event, data, namespace=None, room=None, skip_sid=None,
|
|
callback=None, **kwargs):
|
|
"""Emit a message to a single client, a room, or all the clients
|
|
connected to the namespace.
|
|
|
|
This method takes care or propagating the message to all the servers
|
|
that are connected through the message queue.
|
|
|
|
The parameters are the same as in :meth:`.Server.emit`.
|
|
"""
|
|
if kwargs.get('ignore_queue'):
|
|
return super(PubSubManager, self).emit(
|
|
event, data, namespace=namespace, room=room, skip_sid=skip_sid,
|
|
callback=callback)
|
|
namespace = namespace or '/'
|
|
if callback is not None:
|
|
if self.server is None:
|
|
raise RuntimeError('Callbacks can only be issued from the '
|
|
'context of a server.')
|
|
if room is None:
|
|
raise ValueError('Cannot use callback without a room set.')
|
|
id = self._generate_ack_id(room, callback)
|
|
callback = (room, namespace, id)
|
|
else:
|
|
callback = None
|
|
self._publish({'method': 'emit', 'event': event, 'data': data,
|
|
'namespace': namespace, 'room': room,
|
|
'skip_sid': skip_sid, 'callback': callback,
|
|
'host_id': self.host_id})
|
|
|
|
def can_disconnect(self, sid, namespace):
|
|
if self.is_connected(sid, namespace):
|
|
# client is in this server, so we can disconnect directly
|
|
return super().can_disconnect(sid, namespace)
|
|
else:
|
|
# client is in another server, so we post request to the queue
|
|
self._publish({'method': 'disconnect', 'sid': sid,
|
|
'namespace': namespace or '/'})
|
|
|
|
def disconnect(self, sid, namespace=None, **kwargs):
|
|
if kwargs.get('ignore_queue'):
|
|
return super(PubSubManager, self).disconnect(
|
|
sid, namespace=namespace)
|
|
self._publish({'method': 'disconnect', 'sid': sid,
|
|
'namespace': namespace or '/'})
|
|
|
|
def close_room(self, room, namespace=None):
|
|
self._publish({'method': 'close_room', 'room': room,
|
|
'namespace': namespace or '/'})
|
|
|
|
def _publish(self, data):
|
|
"""Publish a message on the Socket.IO channel.
|
|
|
|
This method needs to be implemented by the different subclasses that
|
|
support pub/sub backends.
|
|
"""
|
|
raise NotImplementedError('This method must be implemented in a '
|
|
'subclass.') # pragma: no cover
|
|
|
|
def _listen(self):
|
|
"""Return the next message published on the Socket.IO channel,
|
|
blocking until a message is available.
|
|
|
|
This method needs to be implemented by the different subclasses that
|
|
support pub/sub backends.
|
|
"""
|
|
raise NotImplementedError('This method must be implemented in a '
|
|
'subclass.') # pragma: no cover
|
|
|
|
def _handle_emit(self, message):
|
|
# Events with callbacks are very tricky to handle across hosts
|
|
# Here in the receiving end we set up a local callback that preserves
|
|
# the callback host and id from the sender
|
|
remote_callback = message.get('callback')
|
|
remote_host_id = message.get('host_id')
|
|
if remote_callback is not None and len(remote_callback) == 3:
|
|
callback = partial(self._return_callback, remote_host_id,
|
|
*remote_callback)
|
|
else:
|
|
callback = None
|
|
super(PubSubManager, self).emit(message['event'], message['data'],
|
|
namespace=message.get('namespace'),
|
|
room=message.get('room'),
|
|
skip_sid=message.get('skip_sid'),
|
|
callback=callback)
|
|
|
|
def _handle_callback(self, message):
|
|
if self.host_id == message.get('host_id'):
|
|
try:
|
|
sid = message['sid']
|
|
id = message['id']
|
|
args = message['args']
|
|
except KeyError:
|
|
return
|
|
self.trigger_callback(sid, id, args)
|
|
|
|
def _return_callback(self, host_id, sid, namespace, callback_id, *args):
|
|
# When an event callback is received, the callback is returned back
|
|
# to the sender, which is identified by the host_id
|
|
self._publish({'method': 'callback', 'host_id': host_id,
|
|
'sid': sid, 'namespace': namespace, 'id': callback_id,
|
|
'args': args})
|
|
|
|
def _handle_disconnect(self, message):
|
|
self.server.disconnect(sid=message.get('sid'),
|
|
namespace=message.get('namespace'),
|
|
ignore_queue=True)
|
|
|
|
def _handle_close_room(self, message):
|
|
super(PubSubManager, self).close_room(
|
|
room=message.get('room'), namespace=message.get('namespace'))
|
|
|
|
def _thread(self):
|
|
for message in self._listen():
|
|
data = None
|
|
if isinstance(message, dict):
|
|
data = message
|
|
else:
|
|
if isinstance(message, bytes): # pragma: no cover
|
|
try:
|
|
data = pickle.loads(message)
|
|
except:
|
|
pass
|
|
if data is None:
|
|
try:
|
|
data = json.loads(message)
|
|
except:
|
|
pass
|
|
if data and 'method' in data:
|
|
self._get_logger().info('pubsub message: {}'.format(
|
|
data['method']))
|
|
try:
|
|
if data['method'] == 'emit':
|
|
self._handle_emit(data)
|
|
elif data['method'] == 'callback':
|
|
self._handle_callback(data)
|
|
elif data['method'] == 'disconnect':
|
|
self._handle_disconnect(data)
|
|
elif data['method'] == 'close_room':
|
|
self._handle_close_room(data)
|
|
except:
|
|
self.server.logger.exception(
|
|
'Unknown error in pubsub listening thread')
|