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# Copyright (c) 2012 - 2021, Anaconda, Inc., and Bokeh Contributors.
# All rights reserved.
#
# The full license is in the file LICENSE.txt, distributed with this software.
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''' Encapsulate handling of all Bokeh Protocol messages a Bokeh server may
receive.
'''
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# Boilerplate
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from __future__ import annotations
import logging # isort:skip
log = logging.getLogger(__name__)
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# Imports
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# Standard library imports
from typing import Any, Callable, Dict
# Bokeh imports
from ..protocol.exceptions import ProtocolError
from .session import ServerSession
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# Globals and constants
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__all__ = (
'ProtocolHandler',
)
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# General API
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[docs]class ProtocolHandler:
''' A Bokeh server may be expected to receive any of the following protocol
messages:
* ``PATCH-DOC``
* ``PULL-DOC-REQ``
* ``PUSH-DOC``
* ``SERVER-INFO-REQ``
The job of ``ProtocolHandler`` is to direct incoming messages to the right
specialized handler for each message type. When the server receives a new
message on a connection it will call ``handler`` with the message and the
connection that the message arrived on. Most messages are ultimately
handled by the ``ServerSession`` class, but some simpler messages types
such as ``SERVER-INFO-REQ`` may be handled directly by ``ProtocolHandler``.
Any unexpected messages will result in a ``ProtocolError``.
'''
_handlers: Dict[str, Callable[..., Any]]
def __init__(self) -> None:
self._handlers = {}
self._handlers['PULL-DOC-REQ'] = ServerSession.pull
self._handlers['PUSH-DOC'] = ServerSession.push
self._handlers['PATCH-DOC'] = ServerSession.patch
self._handlers['SERVER-INFO-REQ'] = self._server_info_req
[docs] async def handle(self, message, connection):
''' Delegate a received message to the appropriate handler.
Args:
message (Message) :
The message that was receive that needs to be handled
connection (ServerConnection) :
The connection that received this message
Raises:
ProtocolError
'''
handler = self._handlers.get(message.msgtype)
if handler is None:
handler = self._handlers.get(message.msgtype)
if handler is None:
raise ProtocolError("%s not expected on server" % message)
try:
work = await handler(message, connection)
except Exception as e:
log.error("error handling message\n message: %r \n error: %r",
message, e, exc_info=True)
work = connection.error(message, repr(e))
return work
async def _server_info_req(self, message, connection):
return connection.protocol.create('SERVER-INFO-REPLY', message.header['msgid'])
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# Dev API
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# Private API
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# Code
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