Revert "Allow room moderators to view redacted event content"

This reverts commit 2dc2979af5.

The feature was merged to upstream, and merging upstream will be cleaner
without this commit here.

synapse/api/errors.py

@@ -79,8 +79,6 @@ class Codes:
     UNABLE_AUTHORISE_JOIN = "M_UNABLE_TO_AUTHORISE_JOIN"
     UNABLE_TO_GRANT_JOIN = "M_UNABLE_TO_GRANT_JOIN"
 
-    UNREDACTED_CONTENT_DELETED = "FI.MAU.MSC2815_UNREDACTED_CONTENT_DELETED"
-
 
 class CodeMessageException(RuntimeError):
     """An exception with integer code and message string attributes.
@@ -485,22 +483,6 @@ class RequestSendFailed(RuntimeError):
         self.can_retry = can_retry
 
 
-class UnredactedContentDeleted(SynapseError):
-    def __init__(self, content_keep_ms: Optional[int] = None):
-        super().__init__(
-            404,
-            "The content for that event has already been erased from the database",
-            errcode=Codes.UNREDACTED_CONTENT_DELETED,
-        )
-        self.content_keep_ms = content_keep_ms
-
-    def error_dict(self) -> "JsonDict":
-        extra = {}
-        if self.content_keep_ms is not None:
-            extra = {"fi.mau.msc2815.content_keep_ms": self.content_keep_ms}
-        return cs_error(self.msg, self.errcode, **extra)
-
-
 def cs_error(msg: str, code: str = Codes.UNKNOWN, **kwargs: Any) -> "JsonDict":
     """Utility method for constructing an error response for client-server
     interactions.

synapse/handlers/events.py

@@ -21,7 +21,6 @@ from synapse.api.errors import AuthError, SynapseError
 from synapse.events import EventBase
 from synapse.events.utils import SerializeEventConfig
 from synapse.handlers.presence import format_user_presence_state
-from synapse.storage.databases.main.events_worker import EventRedactBehaviour
 from synapse.streams.config import PaginationConfig
 from synapse.types import JsonDict, UserID
 from synapse.visibility import filter_events_for_client
@@ -140,11 +139,7 @@ class EventHandler:
         self.storage = hs.get_storage()
 
     async def get_event(
-        self,
+        self, user: UserID, room_id: Optional[str], event_id: str
-        user: UserID,
-        room_id: Optional[str],
-        event_id: str,
-        show_redacted: bool = False,
     ) -> Optional[EventBase]:
         """Retrieve a single specified event.
 
@@ -153,7 +148,6 @@ class EventHandler:
             room_id: The expected room id. We'll return None if the
                 event's room does not match.
             event_id: The event ID to obtain.
-            show_redacted: Should the full content of redacted events be returned?
         Returns:
             An event, or None if there is no event matching this ID.
         Raises:
@@ -161,12 +155,7 @@ class EventHandler:
             AuthError if the user does not have the rights to inspect this
             event.
         """
-        redact_behaviour = (
+        event = await self.store.get_event(event_id, check_room_id=room_id)
-            EventRedactBehaviour.AS_IS if show_redacted else EventRedactBehaviour.REDACT
-        )
-        event = await self.store.get_event(
-            event_id, check_room_id=room_id, redact_behaviour=redact_behaviour
-        )
 
         if not event:
             return None

synapse/rest/client/room.py

@@ -21,7 +21,6 @@ from urllib import parse as urlparse
 
 from twisted.web.server import Request
 
-from synapse import event_auth
 from synapse.api.constants import EventTypes, Membership
 from synapse.api.errors import (
     AuthError,
@@ -30,7 +29,6 @@ from synapse.api.errors import (
     MissingClientTokenError,
     ShadowBanError,
     SynapseError,
-    UnredactedContentDeleted,
 )
 from synapse.api.filtering import Filter
 from synapse.events.utils import format_event_for_client_v2
@@ -649,54 +647,18 @@ class RoomEventServlet(RestServlet):
         super().__init__()
         self.clock = hs.get_clock()
         self._store = hs.get_datastores().main
-        self._state = hs.get_state_handler()
         self.event_handler = hs.get_event_handler()
         self._event_serializer = hs.get_event_client_serializer()
         self._relations_handler = hs.get_relations_handler()
         self.auth = hs.get_auth()
-        self.content_keep_ms = hs.config.server.redaction_retention_period
 
     async def on_GET(
         self, request: SynapseRequest, room_id: str, event_id: str
     ) -> Tuple[int, JsonDict]:
         requester = await self.auth.get_user_by_req(request, allow_guest=True)
-
-        include_unredacted_content = (
-            parse_string(
-                request,
-                "fi.mau.msc2815.include_unredacted_content",
-                allowed_values=("true", "false"),
-            )
-            == "true"
-        )
-        if include_unredacted_content and not await self.auth.is_server_admin(
-            requester.user
-        ):
-            power_level_event = await self._state.get_current_state(
-                room_id, EventTypes.PowerLevels, ""
-            )
-
-            auth_events = {}
-            if power_level_event:
-                auth_events[(EventTypes.PowerLevels, "")] = power_level_event
-
-            redact_level = event_auth.get_named_level(auth_events, "redact", 50)
-            user_level = event_auth.get_user_power_level(
-                requester.user.to_string(), auth_events
-            )
-            if user_level < redact_level:
-                raise SynapseError(
-                    403,
-                    "You don't have permission to view redacted events in this room.",
-                    errcode=Codes.FORBIDDEN,
-                )
-
         try:
             event = await self.event_handler.get_event(
-                requester.user,
+                requester.user, room_id, event_id
-                room_id,
-                event_id,
-                show_redacted=include_unredacted_content,
             )
         except AuthError:
             # This endpoint is supposed to return a 404 when the requester does
@@ -705,11 +667,6 @@ class RoomEventServlet(RestServlet):
             raise SynapseError(404, "Event not found.", errcode=Codes.NOT_FOUND)
 
         if event:
-            if include_unredacted_content and await self._store.have_censored_event(
-                event_id
-            ):
-                raise UnredactedContentDeleted(self.content_keep_ms)
-
             # Ensure there are bundled aggregations available.
             aggregations = await self._relations_handler.get_bundled_aggregations(
                 [event], requester.user.to_string()

synapse/storage/databases/main/events_worker.py

@@ -303,15 +303,6 @@ class EventsWorkerStore(SQLBaseStore):
             desc="get_received_ts",
         )
 
-    async def have_censored_event(self, event_id: str) -> Optional[bool]:
-        return await self.db_pool.simple_select_one_onecol(
-            table="redactions",
-            keyvalues={"redacts": event_id},
-            retcol="have_censored",
-            desc="get_have_censored",
-            allow_none=True,
-        )
-
     # Inform mypy that if allow_none is False (the default) then get_event
     # always returns an EventBase.
     @overload