# -*- coding: utf-8 -*- # Copyright 2015 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 synapse.api.errors import SynapseError from synapse.types import UserID, RoomID class Filtering(object): def __init__(self, hs): super(Filtering, self).__init__() self.store = hs.get_datastore() def get_user_filter(self, user_localpart, filter_id): result = self.store.get_user_filter(user_localpart, filter_id) result.addCallback(Filter) return result def add_user_filter(self, user_localpart, user_filter): self._check_valid_filter(user_filter) return self.store.add_user_filter(user_localpart, user_filter) # TODO(paul): surely we should probably add a delete_user_filter or # replace_user_filter at some point? There's no REST API specified for # them however def _check_valid_filter(self, user_filter_json): """Check if the provided filter is valid. This inspects all definitions contained within the filter. Args: user_filter_json(dict): The filter Raises: SynapseError: If the filter is not valid. """ # NB: Filters are the complete json blobs. "Definitions" are an # individual top-level key e.g. public_user_data. Filters are made of # many definitions. top_level_definitions = [ "public_user_data", "private_user_data", "server_data" ] room_level_definitions = [ "state", "timeline", "ephemeral" ] for key in top_level_definitions: if key in user_filter_json: self._check_definition(user_filter_json[key]) if "room" in user_filter_json: for key in room_level_definitions: if key in user_filter_json["room"]: self._check_definition(user_filter_json["room"][key]) def _check_definition(self, definition): """Check if the provided definition is valid. This inspects not only the types but also the values to make sure they make sense. Args: definition(dict): The filter definition Raises: SynapseError: If there was a problem with this definition. """ # NB: Filters are the complete json blobs. "Definitions" are an # individual top-level key e.g. public_user_data. Filters are made of # many definitions. if type(definition) != dict: raise SynapseError( 400, "Expected JSON object, not %s" % (definition,) ) # check rooms are valid room IDs room_id_keys = ["rooms", "not_rooms"] for key in room_id_keys: if key in definition: if type(definition[key]) != list: raise SynapseError(400, "Expected %s to be a list." % key) for room_id in definition[key]: RoomID.from_string(room_id) # check senders are valid user IDs user_id_keys = ["senders", "not_senders"] for key in user_id_keys: if key in definition: if type(definition[key]) != list: raise SynapseError(400, "Expected %s to be a list." % key) for user_id in definition[key]: UserID.from_string(user_id) # TODO: We don't limit event type values but we probably should... # check types are valid event types event_keys = ["types", "not_types"] for key in event_keys: if key in definition: if type(definition[key]) != list: raise SynapseError(400, "Expected %s to be a list." % key) for event_type in definition[key]: if not isinstance(event_type, basestring): raise SynapseError(400, "Event type should be a string") if "format" in definition: event_format = definition["format"] if event_format not in ["federation", "events"]: raise SynapseError(400, "Invalid format: %s" % (event_format,)) if "select" in definition: event_select_list = definition["select"] for select_key in event_select_list: if select_key not in ["event_id", "origin_server_ts", "thread_id", "content", "content.body"]: raise SynapseError(400, "Bad select: %s" % (select_key,)) if ("bundle_updates" in definition and type(definition["bundle_updates"]) != bool): raise SynapseError(400, "Bad bundle_updates: expected bool.") class Filter(object): def __init__(self, filter_json): self.filter_json = filter_json def timeline_limit(self): return self.filter_json.get("room", {}).get("timeline", {}).get("limit", 10) def presence_limit(self): return self.filter_json.get("presence", {}).get("limit", 10) def ephemeral_limit(self): return self.filter_json.get("room", {}).get("ephemeral", {}).get("limit", 10) def filter_presence(self, events): return self._filter_on_key(events, ["presence"]) def filter_room_state(self, events): return self._filter_on_key(events, ["room", "state"]) def filter_room_timeline(self, events): return self._filter_on_key(events, ["room", "timeline"]) def filter_room_ephemeral(self, events): return self._filter_on_key(events, ["room", "ephemeral"]) def _filter_on_key(self, events, keys): filter_json = self.filter_json if not filter_json: return events try: # extract the right definition from the filter definition = filter_json for key in keys: definition = definition[key] return self._filter_with_definition(events, definition) except KeyError: # return all events if definition isn't specified. return events def _filter_with_definition(self, events, definition): return [e for e in events if self._passes_definition(definition, e)] def _passes_definition(self, definition, event): """Check if the event passes the filter definition Args: definition(dict): The filter definition to check against event(dict or Event): The event to check Returns: True if the event passes the filter in the definition """ if type(event) is dict: room_id = event.get("room_id") sender = event.get("sender") event_type = event["type"] else: room_id = getattr(event, "room_id", None) sender = getattr(event, "sender", None) event_type = event.type return self._event_passes_definition( definition, room_id, sender, event_type ) def _event_passes_definition(self, definition, room_id, sender, event_type): """Check if the event passes through the given definition. Args: definition(dict): The definition to check against. room_id(str): The id of the room this event is in or None. sender(str): The sender of the event event_type(str): The type of the event. Returns: True if the event passes through the filter. """ # Algorithm notes: # For each key in the definition, check the event meets the criteria: # * For types: Literal match or prefix match (if ends with wildcard) # * For senders/rooms: Literal match only # * "not_" checks take presedence (e.g. if "m.*" is in both 'types' # and 'not_types' then it is treated as only being in 'not_types') # room checks if room_id is not None: allow_rooms = definition.get("rooms", None) reject_rooms = definition.get("not_rooms", None) if reject_rooms and room_id in reject_rooms: return False if allow_rooms and room_id not in allow_rooms: return False # sender checks if sender is not None: allow_senders = definition.get("senders", None) reject_senders = definition.get("not_senders", None) if reject_senders and sender in reject_senders: return False if allow_senders and sender not in allow_senders: return False # type checks if "not_types" in definition: for def_type in definition["not_types"]: if self._event_matches_type(event_type, def_type): return False if "types" in definition: included = False for def_type in definition["types"]: if self._event_matches_type(event_type, def_type): included = True break if not included: return False return True def _event_matches_type(self, event_type, def_type): if def_type.endswith("*"): type_prefix = def_type[:-1] return event_type.startswith(type_prefix) else: return event_type == def_type