331 lines
9.9 KiB
Python
331 lines
9.9 KiB
Python
import asyncio
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import secrets
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import logging
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import websockets
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log = logging.getLogger(__name__)
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import syndicate.mini.protocol as protocol
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from syndicate.mini.protocol import Capture, Discard, Observe
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CAPTURE = Capture(Discard())
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from preserves import *
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def _encode(event):
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e = protocol.Encoder()
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e.append(event)
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return e.contents()
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_instance_id = secrets.token_urlsafe(8)
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_uuid_counter = 0
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def uuid(prefix='__@syndicate'):
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global _uuid_counter
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c = _uuid_counter
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_uuid_counter = c + 1
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return prefix + '_' + _instance_id + '_' + str(c)
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def _ignore(*args, **kwargs):
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pass
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class Turn(object):
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def __init__(self, conn):
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self.conn = conn
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self.items = []
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def _extend(self, item):
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self.items.append(item)
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def _reset(self):
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self.items.clear()
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def _commit(self):
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if self.items:
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self.conn._send(protocol.Turn(self.items))
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self._reset()
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def send(self, message):
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self._extend(protocol.Message(message))
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def __enter__(self):
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if self.items:
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raise Exception('Cannot reenter with statement for Turn')
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return self
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def __exit__(self, t, v, tb):
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if t is None:
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self._commit()
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def _fresh_id(assertion):
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return uuid('sub' if Observe.isClassOf(assertion) else 'pub')
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class Endpoint(object):
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def __init__(self, turn, assertion,
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on_add=None, on_del=None, on_msg=None):
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self.assertion = None
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self.id = None
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self.on_add = on_add or _ignore
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self.on_del = on_del or _ignore
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self.on_msg = on_msg or _ignore
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self.cache = set()
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self.set(turn, assertion)
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def set(self, turn, new_assertion, on_transition=None):
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if self.id is not None:
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turn.conn._unmap_endpoint(turn, self, on_end=on_transition)
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self.id = None
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self.assertion = new_assertion
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if self.assertion is not None:
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self.id = _fresh_id(self.assertion)
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turn.conn._map_endpoint(turn, self)
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def clear(self, turn, on_cleared=None):
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self.set(turn, None, on_transition=on_cleared)
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def _reset(self, turn):
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for captures in set(self.cache):
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self._del(turn, captures)
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def _add(self, turn, captures):
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if captures in self.cache:
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log.error('Server error: duplicate captures %r added for endpoint %r %r' % (
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captures,
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self.id,
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self.assertion))
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else:
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self.cache.add(captures)
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self.on_add(turn, *captures)
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def _del(self, turn, captures):
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if captures in self.cache:
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self.cache.discard(captures)
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self.on_del(turn, *captures)
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else:
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log.error('Server error: nonexistent captures %r removed from endpoint %r %r' % (
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captures,
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self.id,
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self.assertion))
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def _msg(self, turn, captures):
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self.on_msg(turn, *captures)
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class DummyEndpoint(object):
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def _add(self, turn, captures): pass
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def _del(self, turn, captures): pass
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def _msg(self, turn, captures): pass
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_dummy_endpoint = DummyEndpoint()
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class Connection(object):
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def __init__(self, scope):
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self.scope = scope
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self.endpoints = {}
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self.end_callbacks = {}
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def _each_endpoint(self):
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return list(self.endpoints.values())
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def turn(self):
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return Turn(self)
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def destroy(self):
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with self.turn() as t:
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for ep in self._each_endpoint():
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ep.clear(t)
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t._reset() ## don't actually Clear the endpoints, we are about to disconnect
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self._disconnect()
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def _unmap_endpoint(self, turn, ep, on_end=None):
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del self.endpoints[ep.id]
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if on_end:
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self.end_callbacks[ep.id] = on_end
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turn._extend(protocol.Clear(ep.id))
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def _on_end(self, turn, id):
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if id in self.end_callbacks:
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self.end_callbacks[id](turn)
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del self.end_callbacks[id]
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def _map_endpoint(self, turn, ep):
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self.endpoints[ep.id] = ep
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turn._extend(protocol.Assert(ep.id, ep.assertion))
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def _on_disconnected(self):
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with self.turn() as t:
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for ep in self._each_endpoint():
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ep._reset(t)
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t._reset() ## we have been disconnected, no point in keeping the actions
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self._disconnect()
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def _on_connected(self):
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self._send(protocol.Connect(self.scope))
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with self.turn() as t:
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for ep in self._each_endpoint():
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self._map_endpoint(t, ep)
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def _lookup(self, endpointId):
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return self.endpoints.get(endpointId, _dummy_endpoint)
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def _on_event(self, v):
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with self.turn() as t:
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self._handle_event(t, v)
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def _handle_event(self, turn, v):
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if protocol.Turn.isClassOf(v):
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for item in protocol.Turn._items(v):
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if protocol.Add.isClassOf(item): self._lookup(item[0])._add(turn, item[1])
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elif protocol.Del.isClassOf(item): self._lookup(item[0])._del(turn, item[1])
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elif protocol.Msg.isClassOf(item): self._lookup(item[0])._msg(turn, item[1])
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elif protocol.End.isClassOf(item): self._on_end(turn, item[0])
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else: log.error('Unhandled server Turn item: %r' % (item,))
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return
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elif protocol.Err.isClassOf(v):
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self._on_error(v[0], v[1])
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return
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elif protocol.Ping.isClassOf(v):
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self._send_bytes(_encode(protocol.Pong()))
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return
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else:
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log.error('Unhandled server message: %r' % (v,))
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def _on_error(self, detail, context):
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log.error('%s: error from server: %r (context: %r)' % (
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self.__class__.__qualname__, detail, context))
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self._disconnect()
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def _send(self, m):
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return self._send_bytes(_encode(m))
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def _send_bytes(self, bs, commitNeeded = False):
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raise Exception('subclassresponsibility')
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def _disconnect(self):
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raise Exception('subclassresponsibility')
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class _StreamConnection(Connection, asyncio.Protocol):
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def __init__(self, scope):
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super().__init__(scope)
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self.decoder = None
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self.stop_signal = None
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self.transport = None
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def connection_lost(self, exc):
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self._on_disconnected()
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def connection_made(self, transport):
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self.transport = transport
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self._on_connected()
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def data_received(self, chunk):
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self.decoder.extend(chunk)
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while True:
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v = self.decoder.try_next()
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if v is None: break
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self._on_event(v)
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def _send_bytes(self, bs, commitNeeded = False):
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if self.transport:
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self.transport.write(bs)
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if commitNeeded:
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self.commitNeeded = True
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def _disconnect(self):
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if self.stop_signal:
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self.stop_signal.get_loop().call_soon_threadsafe(
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lambda: self.stop_signal.set_result(True))
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async def _create_connection(self, loop):
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raise Exception('subclassresponsibility')
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async def main(self, loop, on_connected=None):
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if self.transport is not None:
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raise Exception('Cannot run connection twice!')
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self.decoder = protocol.Decoder()
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self.stop_signal = loop.create_future()
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try:
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_transport, _protocol = await self._create_connection(loop)
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except OSError as e:
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log.error('%s: Could not connect to server: %s' % (self.__class__.__qualname__, e))
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return False
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try:
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if on_connected: on_connected()
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await self.stop_signal
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return True
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finally:
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self.transport.close()
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self.transport = None
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self.stop_signal = None
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self.decoder = None
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class TcpConnection(_StreamConnection):
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def __init__(self, host, port, scope):
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super().__init__(scope)
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self.host = host
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self.port = port
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async def _create_connection(self, loop):
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return await loop.create_connection(lambda: self, self.host, self.port)
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class UnixSocketConnection(_StreamConnection):
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def __init__(self, path, scope):
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super().__init__(scope)
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self.path = path
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async def _create_connection(self, loop):
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return await loop.create_unix_connection(lambda: self, self.path)
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class WebsocketConnection(Connection):
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def __init__(self, url, scope):
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super().__init__(scope)
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self.url = url
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self.loop = None
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self.ws = None
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def _send_bytes(self, bs, commitNeeded = False):
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if self.loop:
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def _do_send():
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if self.ws:
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self.loop.create_task(self.ws.send(bs))
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self.loop.call_soon_threadsafe(_do_send)
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if commitNeeded:
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self.commitNeeded = True
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def _disconnect(self):
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if self.loop:
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def _do_disconnect():
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if self.ws:
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self.loop.create_task(self.ws.close())
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self.loop.call_soon_threadsafe(_do_disconnect)
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async def main(self, loop, on_connected=None):
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if self.ws is not None:
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raise Exception('Cannot run connection twice!')
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self.loop = loop
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try:
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async with websockets.connect(self.url) as ws:
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if on_connected: on_connected()
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self.ws = ws
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self._on_connected()
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try:
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while True:
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chunk = await ws.recv()
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self._on_event(protocol.Decoder(chunk).next())
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except websockets.exceptions.ConnectionClosed:
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pass
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except OSError as e:
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log.error('%s: Could not connect to server: %s' % (self.__class__.__qualname__, e))
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return False
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finally:
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self._on_disconnected()
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if self.ws:
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await self.ws.close()
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self.loop = None
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self.ws = None
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return True
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