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Diffstat (limited to 'synapse/visibility.py')
| -rw-r--r-- | synapse/visibility.py | 210 |
1 files changed, 210 insertions, 0 deletions
diff --git a/synapse/visibility.py b/synapse/visibility.py new file mode 100644 index 0000000000..948ad51772 --- /dev/null +++ b/synapse/visibility.py @@ -0,0 +1,210 @@ +# -*- coding: utf-8 -*- +# Copyright 2014 - 2016 OpenMarket Ltd +# +# Licensed under the Apache License, Version 2.0 (the "License"); +# you may not use this file except in compliance with the License. +# You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +# See the License for the specific language governing permissions and +# limitations under the License. + +from twisted.internet import defer + +from synapse.api.constants import Membership, EventTypes + +from synapse.util.logcontext import preserve_fn + +import logging + + +logger = logging.getLogger(__name__) + + +VISIBILITY_PRIORITY = ( + "world_readable", + "shared", + "invited", + "joined", +) + + +MEMBERSHIP_PRIORITY = ( + Membership.JOIN, + Membership.INVITE, + Membership.KNOCK, + Membership.LEAVE, + Membership.BAN, +) + + +@defer.inlineCallbacks +def filter_events_for_clients(store, user_tuples, events, event_id_to_state): + """ Returns dict of user_id -> list of events that user is allowed to + see. + + Args: + user_tuples (str, bool): (user id, is_peeking) for each user to be + checked. is_peeking should be true if: + * the user is not currently a member of the room, and: + * the user has not been a member of the room since the + given events + events ([synapse.events.EventBase]): list of events to filter + """ + forgotten = yield defer.gatherResults([ + preserve_fn(store.who_forgot_in_room)( + room_id, + ) + for room_id in frozenset(e.room_id for e in events) + ], consumeErrors=True) + + # Set of membership event_ids that have been forgotten + event_id_forgotten = frozenset( + row["event_id"] for rows in forgotten for row in rows + ) + + ignore_dict_content = yield store.get_global_account_data_by_type_for_users( + "m.ignored_user_list", user_ids=[user_id for user_id, _ in user_tuples] + ) + + # FIXME: This will explode if people upload something incorrect. + ignore_dict = { + user_id: frozenset( + content.get("ignored_users", {}).keys() if content else [] + ) + for user_id, content in ignore_dict_content.items() + } + + def allowed(event, user_id, is_peeking, ignore_list): + """ + Args: + event (synapse.events.EventBase): event to check + user_id (str) + is_peeking (bool) + ignore_list (list): list of users to ignore + """ + if not event.is_state() and event.sender in ignore_list: + return False + + state = event_id_to_state[event.event_id] + + # get the room_visibility at the time of the event. + visibility_event = state.get((EventTypes.RoomHistoryVisibility, ""), None) + if visibility_event: + visibility = visibility_event.content.get("history_visibility", "shared") + else: + visibility = "shared" + + if visibility not in VISIBILITY_PRIORITY: + visibility = "shared" + + # if it was world_readable, it's easy: everyone can read it + if visibility == "world_readable": + return True + + # Always allow history visibility events on boundaries. This is done + # by setting the effective visibility to the least restrictive + # of the old vs new. + if event.type == EventTypes.RoomHistoryVisibility: + prev_content = event.unsigned.get("prev_content", {}) + prev_visibility = prev_content.get("history_visibility", None) + + if prev_visibility not in VISIBILITY_PRIORITY: + prev_visibility = "shared" + + new_priority = VISIBILITY_PRIORITY.index(visibility) + old_priority = VISIBILITY_PRIORITY.index(prev_visibility) + if old_priority < new_priority: + visibility = prev_visibility + + # likewise, if the event is the user's own membership event, use + # the 'most joined' membership + membership = None + if event.type == EventTypes.Member and event.state_key == user_id: + membership = event.content.get("membership", None) + if membership not in MEMBERSHIP_PRIORITY: + membership = "leave" + + prev_content = event.unsigned.get("prev_content", {}) + prev_membership = prev_content.get("membership", None) + if prev_membership not in MEMBERSHIP_PRIORITY: + prev_membership = "leave" + + new_priority = MEMBERSHIP_PRIORITY.index(membership) + old_priority = MEMBERSHIP_PRIORITY.index(prev_membership) + if old_priority < new_priority: + membership = prev_membership + + # otherwise, get the user's membership at the time of the event. + if membership is None: + membership_event = state.get((EventTypes.Member, user_id), None) + if membership_event: + if membership_event.event_id not in event_id_forgotten: + membership = membership_event.membership + + # if the user was a member of the room at the time of the event, + # they can see it. + if membership == Membership.JOIN: + return True + + if visibility == "joined": + # we weren't a member at the time of the event, so we can't + # see this event. + return False + + elif visibility == "invited": + # user can also see the event if they were *invited* at the time + # of the event. + return membership == Membership.INVITE + + else: + # visibility is shared: user can also see the event if they have + # become a member since the event + # + # XXX: if the user has subsequently joined and then left again, + # ideally we would share history up to the point they left. But + # we don't know when they left. + return not is_peeking + + defer.returnValue({ + user_id: [ + event + for event in events + if allowed(event, user_id, is_peeking, ignore_dict.get(user_id, [])) + ] + for user_id, is_peeking in user_tuples + }) + + +@defer.inlineCallbacks +def filter_events_for_client(store, user_id, events, is_peeking=False): + """ + Check which events a user is allowed to see + + Args: + user_id(str): user id to be checked + events([synapse.events.EventBase]): list of events to be checked + is_peeking(bool): should be True if: + * the user is not currently a member of the room, and: + * the user has not been a member of the room since the given + events + + Returns: + [synapse.events.EventBase] + """ + types = ( + (EventTypes.RoomHistoryVisibility, ""), + (EventTypes.Member, user_id), + ) + event_id_to_state = yield store.get_state_for_events( + frozenset(e.event_id for e in events), + types=types + ) + res = yield filter_events_for_clients( + store, [(user_id, is_peeking)], events, event_id_to_state + ) + defer.returnValue(res.get(user_id, [])) |