#----------------------------------------------------------------------------- # 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. #----------------------------------------------------------------------------- ''' Provides the Application, Server, and Session context classes. ''' #----------------------------------------------------------------------------- # Boilerplate #----------------------------------------------------------------------------- import logging # isort:skip log = logging.getLogger(__name__) #----------------------------------------------------------------------------- # Imports #----------------------------------------------------------------------------- # External imports from tornado import gen # Bokeh imports from ..application.application import ServerContext, SessionContext from ..document import Document from ..protocol.exceptions import ProtocolError from ..util.token import get_token_payload from ..util.tornado import _CallbackGroup from .session import ServerSession #----------------------------------------------------------------------------- # Globals and constants #----------------------------------------------------------------------------- __all__ = ( 'ApplicationContext', 'BokehServerContext', 'BokehSessionContext', ) #----------------------------------------------------------------------------- # Setup #----------------------------------------------------------------------------- #----------------------------------------------------------------------------- # General API #----------------------------------------------------------------------------- #----------------------------------------------------------------------------- # Dev API #----------------------------------------------------------------------------- [docs]class BokehServerContext(ServerContext): def __init__(self, application_context): self.application_context = application_context self._callbacks = _CallbackGroup(self.application_context.io_loop) def _remove_all_callbacks(self): self._callbacks.remove_all_callbacks() @property def sessions(self): result = [] for session in self.application_context.sessions: result.append(session) return result [docs] def add_next_tick_callback(self, callback): return self._callbacks.add_next_tick_callback(callback) [docs] def remove_next_tick_callback(self, callback_id): self._callbacks.remove_next_tick_callback(callback_id) [docs] def add_timeout_callback(self, callback, timeout_milliseconds): return self._callbacks.add_timeout_callback(callback, timeout_milliseconds) [docs] def remove_timeout_callback(self, callback_id): self._callbacks.remove_timeout_callback(callback_id) [docs] def add_periodic_callback(self, callback, period_milliseconds): return self._callbacks.add_periodic_callback(callback, period_milliseconds) [docs] def remove_periodic_callback(self, callback_id): self._callbacks.remove_periodic_callback(callback_id) [docs]class BokehSessionContext(SessionContext): def __init__(self, session_id, server_context, document, logout_url=None): self._document = document self._session = None self._logout_url = logout_url super().__init__(server_context, session_id) # request arguments used to instantiate this session self._request = None self._token = None def _set_session(self, session): self._session = session [docs] async def with_locked_document(self, func): if self._session is None: # this means we are in on_session_created, so no locking yet, # we have exclusive access await func(self._document) else: await self._session.with_document_locked(func, self._document) @property def destroyed(self): if self._session is None: # this means we are in on_session_created return False else: return self._session.destroyed @property def logout_url(self): return self._logout_url @property def request(self): return self._request @property def token_payload(self): return get_token_payload(self._token) @property def session(self): return self._session [docs]class ApplicationContext: ''' Server-side holder for ``bokeh.application.Application`` plus any associated data. This holds data that's global to all sessions, while ``ServerSession`` holds data specific to an "instance" of the application. ''' def __init__(self, application, io_loop=None, url=None, logout_url=None): self._application = application self._loop = io_loop self._sessions = dict() self._pending_sessions = dict() self._session_contexts = dict() self._server_context = None self._url = url self._logout_url = logout_url @property def io_loop(self): return self._loop @property def application(self): return self._application @property def url(self): return self._url @property def server_context(self): if self._server_context is None: self._server_context = BokehServerContext(self) return self._server_context @property def sessions(self): return self._sessions.values() def run_load_hook(self): try: self._application.on_server_loaded(self.server_context) except Exception as e: log.error("Error in server loaded hook %r", e, exc_info=True) def run_unload_hook(self): try: self._application.on_server_unloaded(self.server_context) except Exception as e: log.error("Error in server unloaded hook %r", e, exc_info=True) self.server_context._remove_all_callbacks() async def create_session_if_needed(self, session_id, request=None, token=None): # this is because empty session_ids would be "falsey" and # potentially open up a way for clients to confuse us if len(session_id) == 0: raise ProtocolError("Session ID must not be empty") if session_id not in self._sessions and \ session_id not in self._pending_sessions: future = self._pending_sessions[session_id] = gen.Future() doc = Document() session_context = BokehSessionContext(session_id, self.server_context, doc, logout_url=self._logout_url) if request is not None: payload = get_token_payload(token) if token else {} # using private attr so users only have access to a read-only property session_context._request = _RequestProxy(request, cookies=payload.get('cookies'), headers=payload.get('headers')) session_context._token = token # expose the session context to the document # use the _attribute to set the public property .session_context doc._session_context = session_context try: await self._application.on_session_created(session_context) except Exception as e: log.error("Failed to run session creation hooks %r", e, exc_info=True) self._application.initialize_document(doc) session = ServerSession(session_id, doc, io_loop=self._loop, token=token) del self._pending_sessions[session_id] self._sessions[session_id] = session session_context._set_session(session) self._session_contexts[session_id] = session_context # notify anyone waiting on the pending session future.set_result(session) if session_id in self._pending_sessions: # another create_session_if_needed is working on # creating this session session = await self._pending_sessions[session_id] else: session = self._sessions[session_id] return session def get_session(self, session_id): if session_id in self._sessions: session = self._sessions[session_id] return session else: raise ProtocolError("No such session " + session_id) async def _discard_session(self, session, should_discard): if session.connection_count > 0: raise RuntimeError("Should not be discarding a session with open connections") log.debug("Discarding session %r last in use %r milliseconds ago", session.id, session.milliseconds_since_last_unsubscribe) session_context = self._session_contexts[session.id] # session.destroy() wants the document lock so it can shut down the document # callbacks. def do_discard(): # while we awaited for the document lock, the discard-worthiness of the # session may have changed. # However, since we have the document lock, our own lock will cause the # block count to be 1. If there's any other block count besides our own, # we want to skip session destruction though. if should_discard(session) and session.expiration_blocked_count == 1: session.destroy() del self._sessions[session.id] del self._session_contexts[session.id] log.trace("Session %r was successfully discarded", session.id) else: log.warning("Session %r was scheduled to discard but came back to life", session.id) await session.with_document_locked(do_discard) # session lifecycle hooks are supposed to be called outside the document lock, # we only run these if we actually ended up destroying the session. if session_context.destroyed: try: await self._application.on_session_destroyed(session_context) except Exception as e: log.error("Failed to run session destroy hooks %r", e, exc_info=True) return None async def _cleanup_sessions(self, unused_session_linger_milliseconds): def should_discard_ignoring_block(session): return session.connection_count == 0 and \ (session.milliseconds_since_last_unsubscribe > unused_session_linger_milliseconds or \ session.expiration_requested) # build a temp list to avoid trouble from self._sessions changes to_discard = [] for session in self._sessions.values(): if should_discard_ignoring_block(session) and not session.expiration_blocked: to_discard.append(session) if len(to_discard) > 0: log.debug("Scheduling %s sessions to discard" % len(to_discard)) # asynchronously reconsider each session for session in to_discard: if should_discard_ignoring_block(session) and not session.expiration_blocked: await self._discard_session(session, should_discard_ignoring_block) return None #----------------------------------------------------------------------------- # Private API #----------------------------------------------------------------------------- class _RequestProxy: def __init__(self, request, cookies=None, headers=None): self._request = request arguments = dict(request.arguments) if 'bokeh-session-id' in arguments: del arguments['bokeh-session-id'] self._arguments = arguments if cookies is not None: self._cookies = cookies elif hasattr(request, 'cookies'): # Django cookies are plain strings, tornado cookies are objects with a value self._cookies = {k: v if isinstance(v, str) else v.value for k, v in request.cookies.items()} else: self._cookies = {} if headers is not None: self._headers = headers elif hasattr(request, 'headers'): self._headers = dict(request.headers) else: self._headers = {} @property def arguments(self): return self._arguments @property def cookies(self): return self._cookies @property def headers(self): return self._headers def __getattr__(self, name): if not name.startswith("_"): val = getattr(self._request, name, None) if val is not None: return val return super().__getattr__(name) #----------------------------------------------------------------------------- # Code #-----------------------------------------------------------------------------