Source code for bokeh.server.protocol_handler
''' Encapsulate handling of all Bokeh Protocol messages a Bokeh server may
receive.
'''
from __future__ import absolute_import
import logging
log = logging.getLogger(__name__)
from tornado import gen
from .session import ServerSession
from ..protocol.exceptions import ProtocolError
[docs]class ProtocolHandler(object):
''' A Bokeh server may be expected to receive any of the following protocol
messages:
* ``EVENT``
* ``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``.
'''
def __init__(self):
self._handlers = dict()
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
self._handlers['EVENT'] = ServerSession.event
[docs] @gen.coroutine
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, message.revision))
if handler is None:
handler = self._handlers.get(message.msgtype)
if handler is None:
raise ProtocolError("%s not expected on server" % message)
try:
work = yield handler(message, connection)
except Exception as e:
log.error("error handling message %r: %r", message, e)
log.debug(" message header %r content %r", message.header, message.content, exc_info=1)
work = connection.error(message, repr(e))
raise gen.Return(work)
@gen.coroutine
def _server_info_req(self, message, connection):
raise gen.Return(connection.protocol.create('SERVER-INFO-REPLY', message.header['msgid']))