#----------------------------------------------------------------------------- # Copyright (c) 2012 - 2019, Anaconda, Inc., and Bokeh Contributors. # All rights reserved. # # The full license is in the file LICENSE.txt, distributed with this software. #----------------------------------------------------------------------------- ''' Implement and provide message protocols for communication between Bokeh Servers and clients. ''' #----------------------------------------------------------------------------- # Boilerplate #----------------------------------------------------------------------------- from __future__ import absolute_import, division, print_function, unicode_literals import logging log = logging.getLogger(__name__) #----------------------------------------------------------------------------- # Imports #----------------------------------------------------------------------------- # Standard library imports # External imports from tornado.escape import json_decode # Bokeh imports from . import messages from . import versions from .exceptions import ProtocolError #----------------------------------------------------------------------------- # Globals and constants #----------------------------------------------------------------------------- __all__ = ( 'Protocol', ) #----------------------------------------------------------------------------- # General API #----------------------------------------------------------------------------- #----------------------------------------------------------------------------- # Dev API #----------------------------------------------------------------------------- [docs]class Protocol(object): ''' Provide a message factory for a given version of the Bokeh Server message protocol. Args: version (str) : a string identifying a protocol version, e.g. "1.0" ''' def __init__(self, version): if version not in versions.spec: raise ProtocolError("Unknown protocol version %r" % version) self._version = version self._messages = dict() for msgtype, revision in versions.spec[version]: self._messages[msgtype] = messages.index[(msgtype, revision)] def __repr__(self): return "Protocol(%r)" % self.version [docs] def create(self, msgtype, *args, **kwargs): ''' Create a new Message instance for the given type. Args: msgtype (str) : ''' if msgtype not in self._messages: raise ProtocolError("Unknown message type %r for protocol version %s" % (msgtype, self._version)) return self._messages[msgtype].create(*args, **kwargs) [docs] def assemble(self, header_json, metadata_json, content_json): ''' Create a Message instance assembled from json fragments. Args: header_json (``JSON``) : metadata_json (``JSON``) : content_json (``JSON``) : Returns: message ''' header = json_decode(header_json) if 'msgtype' not in header: log.error("Bad header with no msgtype was: %r", header) raise ProtocolError("No 'msgtype' in header") return self._messages[header['msgtype']].assemble( header_json, metadata_json, content_json ) @property def version(self): return self._version #----------------------------------------------------------------------------- # Private API #----------------------------------------------------------------------------- #----------------------------------------------------------------------------- # Code #-----------------------------------------------------------------------------