Source code for bokeh.server.protocol_handler

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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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