forked-synapse/synapse/events/__init__.py
2024-03-13 16:46:44 +00:00

557 lines
18 KiB
Python

#
# This file is licensed under the Affero General Public License (AGPL) version 3.
#
# Copyright 2020 The Matrix.org Foundation C.I.C.
# Copyright 2014-2016 OpenMarket Ltd
# Copyright (C) 2023 New Vector, Ltd
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# See the GNU Affero General Public License for more details:
# <https://www.gnu.org/licenses/agpl-3.0.html>.
#
# Originally licensed under the Apache License, Version 2.0:
# <http://www.apache.org/licenses/LICENSE-2.0>.
#
# [This file includes modifications made by New Vector Limited]
#
#
import abc
import collections.abc
import os
from typing import (
TYPE_CHECKING,
Any,
Dict,
Generic,
Iterable,
List,
Optional,
Tuple,
Type,
TypeVar,
Union,
overload,
)
import attr
from typing_extensions import Literal
from unpaddedbase64 import encode_base64
from synapse.api.constants import RelationTypes
from synapse.api.room_versions import EventFormatVersions, RoomVersion, RoomVersions
from synapse.synapse_rust.events import EventInternalMetadata
from synapse.types import JsonDict, StrCollection
from synapse.util.caches import intern_dict
from synapse.util.frozenutils import freeze
from synapse.util.stringutils import strtobool
if TYPE_CHECKING:
from synapse.events.builder import EventBuilder
# Whether we should use frozen_dict in FrozenEvent. Using frozen_dicts prevents
# bugs where we accidentally share e.g. signature dicts. However, converting a
# dict to frozen_dicts is expensive.
#
# NOTE: This is overridden by the configuration by the Synapse worker apps, but
# for the sake of tests, it is set here while it cannot be configured on the
# homeserver object itself.
USE_FROZEN_DICTS = strtobool(os.environ.get("SYNAPSE_USE_FROZEN_DICTS", "0"))
T = TypeVar("T")
# DictProperty (and DefaultDictProperty) require the classes they're used with to
# have a _dict property to pull properties from.
#
# TODO _DictPropertyInstance should not include EventBuilder but due to
# https://github.com/python/mypy/issues/5570 it thinks the DictProperty and
# DefaultDictProperty get applied to EventBuilder when it is in a Union with
# EventBase. This is the least invasive hack to get mypy to comply.
#
# Note that DictProperty/DefaultDictProperty cannot actually be used with
# EventBuilder as it lacks a _dict property.
_DictPropertyInstance = Union["EventBase", "EventBuilder"]
class DictProperty(Generic[T]):
"""An object property which delegates to the `_dict` within its parent object."""
__slots__ = ["key"]
def __init__(self, key: str):
self.key = key
@overload
def __get__(
self,
instance: Literal[None],
owner: Optional[Type[_DictPropertyInstance]] = None,
) -> "DictProperty": ...
@overload
def __get__(
self,
instance: _DictPropertyInstance,
owner: Optional[Type[_DictPropertyInstance]] = None,
) -> T: ...
def __get__(
self,
instance: Optional[_DictPropertyInstance],
owner: Optional[Type[_DictPropertyInstance]] = None,
) -> Union[T, "DictProperty"]:
# if the property is accessed as a class property rather than an instance
# property, return the property itself rather than the value
if instance is None:
return self
try:
assert isinstance(instance, EventBase)
return instance._dict[self.key]
except KeyError as e1:
# We want this to look like a regular attribute error (mostly so that
# hasattr() works correctly), so we convert the KeyError into an
# AttributeError.
#
# To exclude the KeyError from the traceback, we explicitly
# 'raise from e1.__context__' (which is better than 'raise from None',
# because that would omit any *earlier* exceptions).
#
raise AttributeError(
"'%s' has no '%s' property" % (type(instance), self.key)
) from e1.__context__
def __set__(self, instance: _DictPropertyInstance, v: T) -> None:
assert isinstance(instance, EventBase)
instance._dict[self.key] = v
def __delete__(self, instance: _DictPropertyInstance) -> None:
assert isinstance(instance, EventBase)
try:
del instance._dict[self.key]
except KeyError as e1:
raise AttributeError(
"'%s' has no '%s' property" % (type(instance), self.key)
) from e1.__context__
class DefaultDictProperty(DictProperty, Generic[T]):
"""An extension of DictProperty which provides a default if the property is
not present in the parent's _dict.
Note that this means that hasattr() on the property always returns True.
"""
__slots__ = ["default"]
def __init__(self, key: str, default: T):
super().__init__(key)
self.default = default
@overload
def __get__(
self,
instance: Literal[None],
owner: Optional[Type[_DictPropertyInstance]] = None,
) -> "DefaultDictProperty": ...
@overload
def __get__(
self,
instance: _DictPropertyInstance,
owner: Optional[Type[_DictPropertyInstance]] = None,
) -> T: ...
def __get__(
self,
instance: Optional[_DictPropertyInstance],
owner: Optional[Type[_DictPropertyInstance]] = None,
) -> Union[T, "DefaultDictProperty"]:
if instance is None:
return self
assert isinstance(instance, EventBase)
return instance._dict.get(self.key, self.default)
class EventBase(metaclass=abc.ABCMeta):
@property
@abc.abstractmethod
def format_version(self) -> int:
"""The EventFormatVersion implemented by this event"""
...
def __init__(
self,
event_dict: JsonDict,
room_version: RoomVersion,
signatures: Dict[str, Dict[str, str]],
unsigned: JsonDict,
internal_metadata_dict: JsonDict,
rejected_reason: Optional[str],
):
assert room_version.event_format == self.format_version
self.room_version = room_version
self.signatures = signatures
self.unsigned = unsigned
self.rejected_reason = rejected_reason
self._dict = event_dict
self.internal_metadata = EventInternalMetadata(internal_metadata_dict)
depth: DictProperty[int] = DictProperty("depth")
content: DictProperty[JsonDict] = DictProperty("content")
hashes: DictProperty[Dict[str, str]] = DictProperty("hashes")
origin: DictProperty[str] = DictProperty("origin")
origin_server_ts: DictProperty[int] = DictProperty("origin_server_ts")
room_id: DictProperty[str] = DictProperty("room_id")
sender: DictProperty[str] = DictProperty("sender")
# TODO state_key should be Optional[str]. This is generally asserted in Synapse
# by calling is_state() first (which ensures it is not None), but it is hard (not possible?)
# to properly annotate that calling is_state() asserts that state_key exists
# and is non-None. It would be better to replace such direct references with
# get_state_key() (and a check for None).
state_key: DictProperty[str] = DictProperty("state_key")
type: DictProperty[str] = DictProperty("type")
user_id: DictProperty[str] = DictProperty("sender")
@property
def event_id(self) -> str:
raise NotImplementedError()
@property
def membership(self) -> str:
return self.content["membership"]
@property
def redacts(self) -> Optional[str]:
"""MSC2176 moved the redacts field into the content."""
if self.room_version.updated_redaction_rules:
return self.content.get("redacts")
return self.get("redacts")
def is_state(self) -> bool:
return self.get_state_key() is not None
def get_state_key(self) -> Optional[str]:
"""Get the state key of this event, or None if it's not a state event"""
return self._dict.get("state_key")
def get_dict(self) -> JsonDict:
d = dict(self._dict)
d.update({"signatures": self.signatures, "unsigned": dict(self.unsigned)})
return d
def get(self, key: str, default: Optional[Any] = None) -> Any:
return self._dict.get(key, default)
def get_internal_metadata_dict(self) -> JsonDict:
return self.internal_metadata.get_dict()
def get_pdu_json(self, time_now: Optional[int] = None) -> JsonDict:
pdu_json = self.get_dict()
if time_now is not None and "age_ts" in pdu_json["unsigned"]:
age = time_now - pdu_json["unsigned"]["age_ts"]
pdu_json.setdefault("unsigned", {})["age"] = int(age)
del pdu_json["unsigned"]["age_ts"]
# This may be a frozen event
pdu_json["unsigned"].pop("redacted_because", None)
return pdu_json
def get_templated_pdu_json(self) -> JsonDict:
"""
Return a JSON object suitable for a templated event, as used in the
make_{join,leave,knock} workflow.
"""
# By using _dict directly we don't pull in signatures/unsigned.
template_json = dict(self._dict)
# The hashes (similar to the signature) need to be recalculated by the
# joining/leaving/knocking server after (potentially) modifying the
# event.
template_json.pop("hashes")
return template_json
def __getitem__(self, field: str) -> Optional[Any]:
return self._dict[field]
def __contains__(self, field: str) -> bool:
return field in self._dict
def items(self) -> List[Tuple[str, Optional[Any]]]:
return list(self._dict.items())
def keys(self) -> Iterable[str]:
return self._dict.keys()
def prev_event_ids(self) -> List[str]:
"""Returns the list of prev event IDs. The order matches the order
specified in the event, though there is no meaning to it.
Returns:
The list of event IDs of this event's prev_events
"""
return [e for e, _ in self._dict["prev_events"]]
def auth_event_ids(self) -> StrCollection:
"""Returns the list of auth event IDs. The order matches the order
specified in the event, though there is no meaning to it.
Returns:
The list of event IDs of this event's auth_events
"""
return [e for e, _ in self._dict["auth_events"]]
def freeze(self) -> None:
"""'Freeze' the event dict, so it cannot be modified by accident"""
# this will be a no-op if the event dict is already frozen.
self._dict = freeze(self._dict)
def __str__(self) -> str:
return self.__repr__()
def __repr__(self) -> str:
rejection = f"REJECTED={self.rejected_reason}, " if self.rejected_reason else ""
return (
f"<{self.__class__.__name__} "
f"{rejection}"
f"event_id={self.event_id}, "
f"type={self.get('type')}, "
f"state_key={self.get('state_key')}, "
f"outlier={self.internal_metadata.is_outlier()}"
">"
)
class FrozenEvent(EventBase):
format_version = EventFormatVersions.ROOM_V1_V2 # All events of this type are V1
def __init__(
self,
event_dict: JsonDict,
room_version: RoomVersion,
internal_metadata_dict: Optional[JsonDict] = None,
rejected_reason: Optional[str] = None,
):
internal_metadata_dict = internal_metadata_dict or {}
event_dict = dict(event_dict)
# Signatures is a dict of dicts, and this is faster than doing a
# copy.deepcopy
signatures = {
name: dict(sigs.items())
for name, sigs in event_dict.pop("signatures", {}).items()
}
unsigned = dict(event_dict.pop("unsigned", {}))
# We intern these strings because they turn up a lot (especially when
# caching).
event_dict = intern_dict(event_dict)
if USE_FROZEN_DICTS:
frozen_dict = freeze(event_dict)
else:
frozen_dict = event_dict
self._event_id = event_dict["event_id"]
super().__init__(
frozen_dict,
room_version=room_version,
signatures=signatures,
unsigned=unsigned,
internal_metadata_dict=internal_metadata_dict,
rejected_reason=rejected_reason,
)
@property
def event_id(self) -> str:
return self._event_id
class FrozenEventV2(EventBase):
format_version = EventFormatVersions.ROOM_V3 # All events of this type are V2
def __init__(
self,
event_dict: JsonDict,
room_version: RoomVersion,
internal_metadata_dict: Optional[JsonDict] = None,
rejected_reason: Optional[str] = None,
):
internal_metadata_dict = internal_metadata_dict or {}
event_dict = dict(event_dict)
# Signatures is a dict of dicts, and this is faster than doing a
# copy.deepcopy
signatures = {
name: dict(sigs.items())
for name, sigs in event_dict.pop("signatures", {}).items()
}
assert "event_id" not in event_dict
unsigned = dict(event_dict.pop("unsigned", {}))
# We intern these strings because they turn up a lot (especially when
# caching).
event_dict = intern_dict(event_dict)
if USE_FROZEN_DICTS:
frozen_dict = freeze(event_dict)
else:
frozen_dict = event_dict
self._event_id: Optional[str] = None
super().__init__(
frozen_dict,
room_version=room_version,
signatures=signatures,
unsigned=unsigned,
internal_metadata_dict=internal_metadata_dict,
rejected_reason=rejected_reason,
)
@property
def event_id(self) -> str:
# We have to import this here as otherwise we get an import loop which
# is hard to break.
from synapse.crypto.event_signing import compute_event_reference_hash
if self._event_id:
return self._event_id
self._event_id = "$" + encode_base64(compute_event_reference_hash(self)[1])
return self._event_id
def prev_event_ids(self) -> List[str]:
"""Returns the list of prev event IDs. The order matches the order
specified in the event, though there is no meaning to it.
Returns:
The list of event IDs of this event's prev_events
"""
return self._dict["prev_events"]
def auth_event_ids(self) -> StrCollection:
"""Returns the list of auth event IDs. The order matches the order
specified in the event, though there is no meaning to it.
Returns:
The list of event IDs of this event's auth_events
"""
return self._dict["auth_events"]
class FrozenEventV3(FrozenEventV2):
"""FrozenEventV3, which differs from FrozenEventV2 only in the event_id format"""
format_version = EventFormatVersions.ROOM_V4_PLUS # All events of this type are V3
@property
def event_id(self) -> str:
# We have to import this here as otherwise we get an import loop which
# is hard to break.
from synapse.crypto.event_signing import compute_event_reference_hash
if self._event_id:
return self._event_id
self._event_id = "$" + encode_base64(
compute_event_reference_hash(self)[1], urlsafe=True
)
return self._event_id
def _event_type_from_format_version(
format_version: int,
) -> Type[Union[FrozenEvent, FrozenEventV2, FrozenEventV3]]:
"""Returns the python type to use to construct an Event object for the
given event format version.
Args:
format_version: The event format version
Returns:
A type that can be initialized as per the initializer of `FrozenEvent`
"""
if format_version == EventFormatVersions.ROOM_V1_V2:
return FrozenEvent
elif format_version == EventFormatVersions.ROOM_V3:
return FrozenEventV2
elif format_version == EventFormatVersions.ROOM_V4_PLUS:
return FrozenEventV3
else:
raise Exception("No event format %r" % (format_version,))
def make_event_from_dict(
event_dict: JsonDict,
room_version: RoomVersion = RoomVersions.V1,
internal_metadata_dict: Optional[JsonDict] = None,
rejected_reason: Optional[str] = None,
) -> EventBase:
"""Construct an EventBase from the given event dict"""
event_type = _event_type_from_format_version(room_version.event_format)
return event_type(
event_dict, room_version, internal_metadata_dict or {}, rejected_reason
)
@attr.s(slots=True, frozen=True, auto_attribs=True)
class _EventRelation:
# The target event of the relation.
parent_id: str
# The relation type.
rel_type: str
# The aggregation key. Will be None if the rel_type is not m.annotation or is
# not a string.
aggregation_key: Optional[str]
def relation_from_event(event: EventBase) -> Optional[_EventRelation]:
"""
Attempt to parse relation information an event.
Returns:
The event relation information, if it is valid. None, otherwise.
"""
relation = event.content.get("m.relates_to")
if not relation or not isinstance(relation, collections.abc.Mapping):
# No relation information.
return None
# Relations must have a type and parent event ID.
rel_type = relation.get("rel_type")
if not isinstance(rel_type, str):
return None
parent_id = relation.get("event_id")
if not isinstance(parent_id, str):
return None
# Annotations have a key field.
aggregation_key = None
if rel_type == RelationTypes.ANNOTATION:
aggregation_key = relation.get("key")
if not isinstance(aggregation_key, str):
aggregation_key = None
return _EventRelation(parent_id, rel_type, aggregation_key)