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- # -*- 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.
- import attr
- from twisted.internet import defer
- from synapse.api.constants import MAX_DEPTH
- from synapse.api.errors import UnsupportedRoomVersionError
- from synapse.api.room_versions import (
- KNOWN_EVENT_FORMAT_VERSIONS,
- KNOWN_ROOM_VERSIONS,
- EventFormatVersions,
- )
- from synapse.crypto.event_signing import add_hashes_and_signatures
- from synapse.types import EventID
- from synapse.util.stringutils import random_string
- from . import _EventInternalMetadata, event_type_from_format_version
- @attr.s(slots=True, cmp=False, frozen=True)
- class EventBuilder(object):
- """A format independent event builder used to build up the event content
- before signing the event.
- (Note that while objects of this class are frozen, the
- content/unsigned/internal_metadata fields are still mutable)
- Attributes:
- format_version (int): Event format version
- room_id (str)
- type (str)
- sender (str)
- content (dict)
- unsigned (dict)
- internal_metadata (_EventInternalMetadata)
- _state (StateHandler)
- _auth (synapse.api.Auth)
- _store (DataStore)
- _clock (Clock)
- _hostname (str): The hostname of the server creating the event
- _signing_key: The signing key to use to sign the event as the server
- """
- _state = attr.ib()
- _auth = attr.ib()
- _store = attr.ib()
- _clock = attr.ib()
- _hostname = attr.ib()
- _signing_key = attr.ib()
- format_version = attr.ib()
- room_id = attr.ib()
- type = attr.ib()
- sender = attr.ib()
- content = attr.ib(default=attr.Factory(dict))
- unsigned = attr.ib(default=attr.Factory(dict))
- # These only exist on a subset of events, so they raise AttributeError if
- # someone tries to get them when they don't exist.
- _state_key = attr.ib(default=None)
- _redacts = attr.ib(default=None)
- _origin_server_ts = attr.ib(default=None)
- internal_metadata = attr.ib(
- default=attr.Factory(lambda: _EventInternalMetadata({}))
- )
- @property
- def state_key(self):
- if self._state_key is not None:
- return self._state_key
- raise AttributeError("state_key")
- def is_state(self):
- return self._state_key is not None
- @defer.inlineCallbacks
- def build(self, prev_event_ids):
- """Transform into a fully signed and hashed event
- Args:
- prev_event_ids (list[str]): The event IDs to use as the prev events
- Returns:
- Deferred[FrozenEvent]
- """
- state_ids = yield self._state.get_current_state_ids(
- self.room_id, prev_event_ids
- )
- auth_ids = yield self._auth.compute_auth_events(self, state_ids)
- if self.format_version == EventFormatVersions.V1:
- auth_events = yield self._store.add_event_hashes(auth_ids)
- prev_events = yield self._store.add_event_hashes(prev_event_ids)
- else:
- auth_events = auth_ids
- prev_events = prev_event_ids
- old_depth = yield self._store.get_max_depth_of(prev_event_ids)
- depth = old_depth + 1
- # we cap depth of generated events, to ensure that they are not
- # rejected by other servers (and so that they can be persisted in
- # the db)
- depth = min(depth, MAX_DEPTH)
- event_dict = {
- "auth_events": auth_events,
- "prev_events": prev_events,
- "type": self.type,
- "room_id": self.room_id,
- "sender": self.sender,
- "content": self.content,
- "unsigned": self.unsigned,
- "depth": depth,
- "prev_state": [],
- }
- if self.is_state():
- event_dict["state_key"] = self._state_key
- if self._redacts is not None:
- event_dict["redacts"] = self._redacts
- if self._origin_server_ts is not None:
- event_dict["origin_server_ts"] = self._origin_server_ts
- return create_local_event_from_event_dict(
- clock=self._clock,
- hostname=self._hostname,
- signing_key=self._signing_key,
- format_version=self.format_version,
- event_dict=event_dict,
- internal_metadata_dict=self.internal_metadata.get_dict(),
- )
- class EventBuilderFactory(object):
- def __init__(self, hs):
- self.clock = hs.get_clock()
- self.hostname = hs.hostname
- self.signing_key = hs.config.signing_key[0]
- self.store = hs.get_datastore()
- self.state = hs.get_state_handler()
- self.auth = hs.get_auth()
- def new(self, room_version, key_values):
- """Generate an event builder appropriate for the given room version
- Deprecated: use for_room_version with a RoomVersion object instead
- Args:
- room_version (str): Version of the room that we're creating an event builder
- for
- key_values (dict): Fields used as the basis of the new event
- Returns:
- EventBuilder
- """
- v = KNOWN_ROOM_VERSIONS.get(room_version)
- if not v:
- # this can happen if support is withdrawn for a room version
- raise UnsupportedRoomVersionError()
- return self.for_room_version(v, key_values)
- def for_room_version(self, room_version, key_values):
- """Generate an event builder appropriate for the given room version
- Args:
- room_version (synapse.api.room_versions.RoomVersion):
- Version of the room that we're creating an event builder for
- key_values (dict): Fields used as the basis of the new event
- Returns:
- EventBuilder
- """
- return EventBuilder(
- store=self.store,
- state=self.state,
- auth=self.auth,
- clock=self.clock,
- hostname=self.hostname,
- signing_key=self.signing_key,
- format_version=room_version.event_format,
- type=key_values["type"],
- state_key=key_values.get("state_key"),
- room_id=key_values["room_id"],
- sender=key_values["sender"],
- content=key_values.get("content", {}),
- unsigned=key_values.get("unsigned", {}),
- redacts=key_values.get("redacts", None),
- origin_server_ts=key_values.get("origin_server_ts", None),
- )
- def create_local_event_from_event_dict(
- clock,
- hostname,
- signing_key,
- format_version,
- event_dict,
- internal_metadata_dict=None,
- ):
- """Takes a fully formed event dict, ensuring that fields like `origin`
- and `origin_server_ts` have correct values for a locally produced event,
- then signs and hashes it.
- Args:
- clock (Clock)
- hostname (str)
- signing_key
- format_version (int)
- event_dict (dict)
- internal_metadata_dict (dict|None)
- Returns:
- FrozenEvent
- """
- if format_version not in KNOWN_EVENT_FORMAT_VERSIONS:
- raise Exception("No event format defined for version %r" % (format_version,))
- if internal_metadata_dict is None:
- internal_metadata_dict = {}
- time_now = int(clock.time_msec())
- if format_version == EventFormatVersions.V1:
- event_dict["event_id"] = _create_event_id(clock, hostname)
- event_dict["origin"] = hostname
- event_dict.setdefault("origin_server_ts", time_now)
- event_dict.setdefault("unsigned", {})
- age = event_dict["unsigned"].pop("age", 0)
- event_dict["unsigned"].setdefault("age_ts", time_now - age)
- event_dict.setdefault("signatures", {})
- add_hashes_and_signatures(event_dict, hostname, signing_key)
- return event_type_from_format_version(format_version)(
- event_dict, internal_metadata_dict=internal_metadata_dict
- )
- # A counter used when generating new event IDs
- _event_id_counter = 0
- def _create_event_id(clock, hostname):
- """Create a new event ID
- Args:
- clock (Clock)
- hostname (str): The server name for the event ID
- Returns:
- str
- """
- global _event_id_counter
- i = str(_event_id_counter)
- _event_id_counter += 1
- local_part = str(int(clock.time())) + i + random_string(5)
- e_id = EventID(local_part, hostname)
- return e_id.to_string()
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