diff --git a/synapse/events/third_party_rules.py b/synapse/events/third_party_rules.py
index f7944fd834..7a6eb3e516 100644
--- a/synapse/events/third_party_rules.py
+++ b/synapse/events/third_party_rules.py
@@ -11,16 +11,124 @@
# 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 logging
+from typing import TYPE_CHECKING, Awaitable, Callable, List, Optional, Tuple
-from typing import TYPE_CHECKING, Union
-
+from synapse.api.errors import SynapseError
from synapse.events import EventBase
from synapse.events.snapshot import EventContext
from synapse.types import Requester, StateMap
+from synapse.util.async_helpers import maybe_awaitable
if TYPE_CHECKING:
from synapse.server import HomeServer
+logger = logging.getLogger(__name__)
+
+
+CHECK_EVENT_ALLOWED_CALLBACK = Callable[
+ [EventBase, StateMap[EventBase]], Awaitable[Tuple[bool, Optional[dict]]]
+]
+ON_CREATE_ROOM_CALLBACK = Callable[[Requester, dict, bool], Awaitable]
+CHECK_THREEPID_CAN_BE_INVITED_CALLBACK = Callable[
+ [str, str, StateMap[EventBase]], Awaitable[bool]
+]
+CHECK_VISIBILITY_CAN_BE_MODIFIED_CALLBACK = Callable[
+ [str, StateMap[EventBase], str], Awaitable[bool]
+]
+
+
+def load_legacy_third_party_event_rules(hs: "HomeServer"):
+ """Wrapper that loads a third party event rules module configured using the old
+ configuration, and registers the hooks they implement.
+ """
+ if hs.config.third_party_event_rules is None:
+ return
+
+ module, config = hs.config.third_party_event_rules
+
+ api = hs.get_module_api()
+ third_party_rules = module(config=config, module_api=api)
+
+ # The known hooks. If a module implements a method which name appears in this set,
+ # we'll want to register it.
+ third_party_event_rules_methods = {
+ "check_event_allowed",
+ "on_create_room",
+ "check_threepid_can_be_invited",
+ "check_visibility_can_be_modified",
+ }
+
+ def async_wrapper(f: Optional[Callable]) -> Optional[Callable[..., Awaitable]]:
+ # f might be None if the callback isn't implemented by the module. In this
+ # case we don't want to register a callback at all so we return None.
+ if f is None:
+ return None
+
+ # We return a separate wrapper for these methods because, in order to wrap them
+ # correctly, we need to await its result. Therefore it doesn't make a lot of
+ # sense to make it go through the run() wrapper.
+ if f.__name__ == "check_event_allowed":
+
+ # We need to wrap check_event_allowed because its old form would return either
+ # a boolean or a dict, but now we want to return the dict separately from the
+ # boolean.
+ async def wrap_check_event_allowed(
+ event: EventBase,
+ state_events: StateMap[EventBase],
+ ) -> Tuple[bool, Optional[dict]]:
+ # We've already made sure f is not None above, but mypy doesn't do well
+ # across function boundaries so we need to tell it f is definitely not
+ # None.
+ assert f is not None
+
+ res = await f(event, state_events)
+ if isinstance(res, dict):
+ return True, res
+ else:
+ return res, None
+
+ return wrap_check_event_allowed
+
+ if f.__name__ == "on_create_room":
+
+ # We need to wrap on_create_room because its old form would return a boolean
+ # if the room creation is denied, but now we just want it to raise an
+ # exception.
+ async def wrap_on_create_room(
+ requester: Requester, config: dict, is_requester_admin: bool
+ ) -> None:
+ # We've already made sure f is not None above, but mypy doesn't do well
+ # across function boundaries so we need to tell it f is definitely not
+ # None.
+ assert f is not None
+
+ res = await f(requester, config, is_requester_admin)
+ if res is False:
+ raise SynapseError(
+ 403,
+ "Room creation forbidden with these parameters",
+ )
+
+ return wrap_on_create_room
+
+ def run(*args, **kwargs):
+ # mypy doesn't do well across function boundaries so we need to tell it
+ # f is definitely not None.
+ assert f is not None
+
+ return maybe_awaitable(f(*args, **kwargs))
+
+ return run
+
+ # Register the hooks through the module API.
+ hooks = {
+ hook: async_wrapper(getattr(third_party_rules, hook, None))
+ for hook in third_party_event_rules_methods
+ }
+
+ api.register_third_party_rules_callbacks(**hooks)
+
class ThirdPartyEventRules:
"""Allows server admins to provide a Python module implementing an extra
@@ -35,36 +143,65 @@ class ThirdPartyEventRules:
self.store = hs.get_datastore()
- module = None
- config = None
- if hs.config.third_party_event_rules:
- module, config = hs.config.third_party_event_rules
+ self._check_event_allowed_callbacks: List[CHECK_EVENT_ALLOWED_CALLBACK] = []
+ self._on_create_room_callbacks: List[ON_CREATE_ROOM_CALLBACK] = []
+ self._check_threepid_can_be_invited_callbacks: List[
+ CHECK_THREEPID_CAN_BE_INVITED_CALLBACK
+ ] = []
+ self._check_visibility_can_be_modified_callbacks: List[
+ CHECK_VISIBILITY_CAN_BE_MODIFIED_CALLBACK
+ ] = []
+
+ def register_third_party_rules_callbacks(
+ self,
+ check_event_allowed: Optional[CHECK_EVENT_ALLOWED_CALLBACK] = None,
+ on_create_room: Optional[ON_CREATE_ROOM_CALLBACK] = None,
+ check_threepid_can_be_invited: Optional[
+ CHECK_THREEPID_CAN_BE_INVITED_CALLBACK
+ ] = None,
+ check_visibility_can_be_modified: Optional[
+ CHECK_VISIBILITY_CAN_BE_MODIFIED_CALLBACK
+ ] = None,
+ ):
+ """Register callbacks from modules for each hook."""
+ if check_event_allowed is not None:
+ self._check_event_allowed_callbacks.append(check_event_allowed)
+
+ if on_create_room is not None:
+ self._on_create_room_callbacks.append(on_create_room)
+
+ if check_threepid_can_be_invited is not None:
+ self._check_threepid_can_be_invited_callbacks.append(
+ check_threepid_can_be_invited,
+ )
- if module is not None:
- self.third_party_rules = module(
- config=config,
- module_api=hs.get_module_api(),
+ if check_visibility_can_be_modified is not None:
+ self._check_visibility_can_be_modified_callbacks.append(
+ check_visibility_can_be_modified,
)
async def check_event_allowed(
self, event: EventBase, context: EventContext
- ) -> Union[bool, dict]:
+ ) -> Tuple[bool, Optional[dict]]:
"""Check if a provided event should be allowed in the given context.
The module can return:
* True: the event is allowed.
* False: the event is not allowed, and should be rejected with M_FORBIDDEN.
- * a dict: replacement event data.
+
+ If the event is allowed, the module can also return a dictionary to use as a
+ replacement for the event.
Args:
event: The event to be checked.
context: The context of the event.
Returns:
- The result from the ThirdPartyRules module, as above
+ The result from the ThirdPartyRules module, as above.
"""
- if self.third_party_rules is None:
- return True
+ # Bail out early without hitting the store if we don't have any callbacks to run.
+ if len(self._check_event_allowed_callbacks) == 0:
+ return True, None
prev_state_ids = await context.get_prev_state_ids()
@@ -77,29 +214,46 @@ class ThirdPartyEventRules:
# the hashes and signatures.
event.freeze()
- return await self.third_party_rules.check_event_allowed(event, state_events)
+ for callback in self._check_event_allowed_callbacks:
+ try:
+ res, replacement_data = await callback(event, state_events)
+ except Exception as e:
+ logger.warning("Failed to run module API callback %s: %s", callback, e)
+ continue
+
+ # Return if the event shouldn't be allowed or if the module came up with a
+ # replacement dict for the event.
+ if res is False:
+ return res, None
+ elif isinstance(replacement_data, dict):
+ return True, replacement_data
+
+ return True, None
async def on_create_room(
self, requester: Requester, config: dict, is_requester_admin: bool
- ) -> bool:
- """Intercept requests to create room to allow, deny or update the
- request config.
+ ) -> None:
+ """Intercept requests to create room to maybe deny it (via an exception) or
+ update the request config.
Args:
requester
config: The creation config from the client.
is_requester_admin: If the requester is an admin
-
- Returns:
- Whether room creation is allowed or denied.
"""
-
- if self.third_party_rules is None:
- return True
-
- return await self.third_party_rules.on_create_room(
- requester, config, is_requester_admin
- )
+ for callback in self._on_create_room_callbacks:
+ try:
+ await callback(requester, config, is_requester_admin)
+ except Exception as e:
+ # Don't silence the errors raised by this callback since we expect it to
+ # raise an exception to deny the creation of the room; instead make sure
+ # it's a SynapseError we can send to clients.
+ if not isinstance(e, SynapseError):
+ e = SynapseError(
+ 403, "Room creation forbidden with these parameters"
+ )
+
+ raise e
async def check_threepid_can_be_invited(
self, medium: str, address: str, room_id: str
@@ -114,15 +268,20 @@ class ThirdPartyEventRules:
Returns:
True if the 3PID can be invited, False if not.
"""
-
- if self.third_party_rules is None:
+ # Bail out early without hitting the store if we don't have any callbacks to run.
+ if len(self._check_threepid_can_be_invited_callbacks) == 0:
return True
state_events = await self._get_state_map_for_room(room_id)
- return await self.third_party_rules.check_threepid_can_be_invited(
- medium, address, state_events
- )
+ for callback in self._check_threepid_can_be_invited_callbacks:
+ try:
+ if await callback(medium, address, state_events) is False:
+ return False
+ except Exception as e:
+ logger.warning("Failed to run module API callback %s: %s", callback, e)
+
+ return True
async def check_visibility_can_be_modified(
self, room_id: str, new_visibility: str
@@ -137,18 +296,20 @@ class ThirdPartyEventRules:
Returns:
True if the room's visibility can be modified, False if not.
"""
- if self.third_party_rules is None:
- return True
-
- check_func = getattr(
- self.third_party_rules, "check_visibility_can_be_modified", None
- )
- if not check_func or not callable(check_func):
+ # Bail out early without hitting the store if we don't have any callback
+ if len(self._check_visibility_can_be_modified_callbacks) == 0:
return True
state_events = await self._get_state_map_for_room(room_id)
- return await check_func(room_id, state_events, new_visibility)
+ for callback in self._check_visibility_can_be_modified_callbacks:
+ try:
+ if await callback(room_id, state_events, new_visibility) is False:
+ return False
+ except Exception as e:
+ logger.warning("Failed to run module API callback %s: %s", callback, e)
+
+ return True
async def _get_state_map_for_room(self, room_id: str) -> StateMap[EventBase]:
"""Given a room ID, return the state events of that room.
|
