Source code for bokeh.client.websocket
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# Copyright (c) 2012 - 2018, Anaconda, Inc. All rights reserved.
#
# Powered by the Bokeh Development Team.
#
# The full license is in the file LICENSE.txt, distributed with this software.
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''' Provide a low-level wrapper for Tornado Websockets that adds locking
and smooths some compatibility issues.
'''
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# Boilerplate
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from __future__ import absolute_import, division, print_function, unicode_literals
import logging
log = logging.getLogger(__name__)
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# Imports
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# Standard library imports
# External imports
from tornado import gen, locks
from tornado.websocket import WebSocketError
# Bokeh imports
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# Globals and constants
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__all__ = (
'WebSocketClientConnectionWrapper',
)
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# General API
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# Dev API
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[docs]class WebSocketClientConnectionWrapper(object):
''' Used for compat across Tornado versions and to add write_lock'''
def __init__(self, socket):
if socket is None:
raise ValueError("socket must not be None")
self._socket = socket
# write_lock allows us to lock the connection to send multiple
# messages atomically.
self.write_lock = locks.Lock()
# Internal methods --------------------------------------------------------
[docs] @gen.coroutine
def write_message(self, message, binary=False, locked=True):
''' Write a message to the websocket after obtaining the appropriate
Bokeh Document lock.
'''
def write_message_unlocked():
if self._socket.protocol is None:
# Tornado is maybe supposed to do this, but in fact it
# tries to do _socket.protocol.write_message when protocol
# is None and throws AttributeError or something. So avoid
# trying to write to the closed socket. There doesn't seem
# to be an obvious public function to check if the socket
# is closed.
raise WebSocketError("Connection to the server has been closed")
future = self._socket.write_message(message, binary)
# don't yield this future or we're blocking on ourselves!
raise gen.Return(future)
if locked:
with (yield self.write_lock.acquire()):
write_message_unlocked()
else:
write_message_unlocked()
[docs] def close(self, code=None, reason=None):
''' Close the websocket. '''
return self._socket.close(code, reason)
[docs] def read_message(self, callback=None):
''' Read a message from websocket and execute a callback.
'''
return self._socket.read_message(callback)
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# Private API
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# Code
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