diff options
Diffstat (limited to 'synapse/events/builder.py')
| -rw-r--r-- | synapse/events/builder.py | 279 |
1 files changed, 243 insertions, 36 deletions
diff --git a/synapse/events/builder.py b/synapse/events/builder.py index e662eaef10..06e01be918 100644 --- a/synapse/events/builder.py +++ b/synapse/events/builder.py @@ -13,63 +13,270 @@ # See the License for the specific language governing permissions and # limitations under the License. -import copy +import attr +from twisted.internet import defer + +from synapse.api.constants import ( + KNOWN_EVENT_FORMAT_VERSIONS, + KNOWN_ROOM_VERSIONS, + MAX_DEPTH, + 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 EventBase, FrozenEvent, _event_dict_property +from . import ( + _EventInternalMetadata, + event_type_from_format_version, + room_version_to_event_format, +) + + +@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) + internal_metadata = attr.ib(default=attr.Factory(lambda: _EventInternalMetadata({}))) -class EventBuilder(EventBase): - def __init__(self, key_values={}, internal_metadata_dict={}): - signatures = copy.deepcopy(key_values.pop("signatures", {})) - unsigned = copy.deepcopy(key_values.pop("unsigned", {})) + @property + def state_key(self): + if self._state_key is not None: + return self._state_key - super(EventBuilder, self).__init__( - key_values, - signatures=signatures, - unsigned=unsigned, - internal_metadata_dict=internal_metadata_dict, + 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, ) - event_id = _event_dict_property("event_id") - state_key = _event_dict_property("state_key") - type = _event_dict_property("type") + 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 - def build(self): - return FrozenEvent.from_event(self) + if self._redacts is not None: + event_dict["redacts"] = self._redacts + + defer.returnValue( + 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, clock, hostname): - self.clock = clock - self.hostname = hostname + 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 + + 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 + """ + + # There's currently only the one event version defined + if room_version not in KNOWN_ROOM_VERSIONS: + raise Exception( + "No event format defined for version %r" % (room_version,) + ) + + 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_to_event_format(room_version), + 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), + ) + + +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 + """ + + # There's currently only the one event version defined + 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["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, + ) - self.event_id_count = 0 - def create_event_id(self): - i = str(self.event_id_count) - self.event_id_count += 1 +# A counter used when generating new event IDs +_event_id_counter = 0 - local_part = str(int(self.clock.time())) + i + random_string(5) - e_id = EventID(local_part, self.hostname) +def _create_event_id(clock, hostname): + """Create a new event ID - return e_id.to_string() + Args: + clock (Clock) + hostname (str): The server name for the event ID - def new(self, key_values={}): - key_values["event_id"] = self.create_event_id() + Returns: + str + """ - time_now = int(self.clock.time_msec()) + global _event_id_counter - key_values.setdefault("origin", self.hostname) - key_values.setdefault("origin_server_ts", time_now) + i = str(_event_id_counter) + _event_id_counter += 1 - key_values.setdefault("unsigned", {}) - age = key_values["unsigned"].pop("age", 0) - key_values["unsigned"].setdefault("age_ts", time_now - age) + local_part = str(int(clock.time())) + i + random_string(5) - key_values["signatures"] = {} + e_id = EventID(local_part, hostname) - return EventBuilder(key_values=key_values,) + return e_id.to_string() |