Remove the deprecated BaseHandler. (#11005)

The shared ratelimit function was replaced with a dedicated
RequestRatelimiter class (accessible from the HomeServer
object).

Other properties were copied to each sub-class that inherited
from BaseHandler.

24 files changed, 166 insertions, 215 deletions

diff --git a/changelog.d/11005.misc b/changelog.d/11005.misc
new file mode 100644
index 0000000000..a893591971
--- /dev/null
+++ b/changelog.d/11005.misc
@@ -0,0 +1 @@
+Remove the deprecated `BaseHandler` object.
diff --git a/synapse/api/ratelimiting.py b/synapse/api/ratelimiting.py
index cbdd74025b..e8964097d3 100644
--- a/synapse/api/ratelimiting.py
+++ b/synapse/api/ratelimiting.py
@@ -17,6 +17,7 @@ from collections import OrderedDict
 from typing import Hashable, Optional, Tuple
 
 from synapse.api.errors import LimitExceededError
+from synapse.config.ratelimiting import RateLimitConfig
 from synapse.storage.databases.main import DataStore
 from synapse.types import Requester
 from synapse.util import Clock
@@ -233,3 +234,88 @@ class Ratelimiter:
             raise LimitExceededError(
                 retry_after_ms=int(1000 * (time_allowed - time_now_s))
             )
+
+
+class RequestRatelimiter:
+    def __init__(
+        self,
+        store: DataStore,
+        clock: Clock,
+        rc_message: RateLimitConfig,
+        rc_admin_redaction: Optional[RateLimitConfig],
+    ):
+        self.store = store
+        self.clock = clock
+
+        # The rate_hz and burst_count are overridden on a per-user basis
+        self.request_ratelimiter = Ratelimiter(
+            store=self.store, clock=self.clock, rate_hz=0, burst_count=0
+        )
+        self._rc_message = rc_message
+
+        # Check whether ratelimiting room admin message redaction is enabled
+        # by the presence of rate limits in the config
+        if rc_admin_redaction:
+            self.admin_redaction_ratelimiter: Optional[Ratelimiter] = Ratelimiter(
+                store=self.store,
+                clock=self.clock,
+                rate_hz=rc_admin_redaction.per_second,
+                burst_count=rc_admin_redaction.burst_count,
+            )
+        else:
+            self.admin_redaction_ratelimiter = None
+
+    async def ratelimit(
+        self,
+        requester: Requester,
+        update: bool = True,
+        is_admin_redaction: bool = False,
+    ) -> None:
+        """Ratelimits requests.
+
+        Args:
+            requester
+            update: Whether to record that a request is being processed.
+                Set to False when doing multiple checks for one request (e.g.
+                to check up front if we would reject the request), and set to
+                True for the last call for a given request.
+            is_admin_redaction: Whether this is a room admin/moderator
+                redacting an event. If so then we may apply different
+                ratelimits depending on config.
+
+        Raises:
+            LimitExceededError if the request should be ratelimited
+        """
+        user_id = requester.user.to_string()
+
+        # The AS user itself is never rate limited.
+        app_service = self.store.get_app_service_by_user_id(user_id)
+        if app_service is not None:
+            return  # do not ratelimit app service senders
+
+        messages_per_second = self._rc_message.per_second
+        burst_count = self._rc_message.burst_count
+
+        # Check if there is a per user override in the DB.
+        override = await self.store.get_ratelimit_for_user(user_id)
+        if override:
+            # If overridden with a null Hz then ratelimiting has been entirely
+            # disabled for the user
+            if not override.messages_per_second:
+                return
+
+            messages_per_second = override.messages_per_second
+            burst_count = override.burst_count
+
+        if is_admin_redaction and self.admin_redaction_ratelimiter:
+            # If we have separate config for admin redactions, use a separate
+            # ratelimiter as to not have user_ids clash
+            await self.admin_redaction_ratelimiter.ratelimit(requester, update=update)
+        else:
+            # Override rate and burst count per-user
+            await self.request_ratelimiter.ratelimit(
+                requester,
+                rate_hz=messages_per_second,
+                burst_count=burst_count,
+                update=update,
+            )
diff --git a/synapse/handlers/_base.py b/synapse/handlers/_base.py
deleted file mode 100644
index 0ccef884e7..0000000000
--- a/synapse/handlers/_base.py
+++ /dev/null
@@ -1,120 +0,0 @@
-# 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 logging
-from typing import TYPE_CHECKING, Optional
-
-from synapse.api.ratelimiting import Ratelimiter
-from synapse.types import Requester
-
-if TYPE_CHECKING:
-    from synapse.server import HomeServer
-
-logger = logging.getLogger(__name__)
-
-
-class BaseHandler:
-    """
-    Common base class for the event handlers.
-
-    Deprecated: new code should not use this. Instead, Handler classes should define the
-    fields they actually need. The utility methods should either be factored out to
-    standalone helper functions, or to different Handler classes.
-    """
-
-    def __init__(self, hs: "HomeServer"):
-        self.store = hs.get_datastore()
-        self.auth = hs.get_auth()
-        self.notifier = hs.get_notifier()
-        self.state_handler = hs.get_state_handler()
-        self.distributor = hs.get_distributor()
-        self.clock = hs.get_clock()
-        self.hs = hs
-
-        # The rate_hz and burst_count are overridden on a per-user basis
-        self.request_ratelimiter = Ratelimiter(
-            store=self.store, clock=self.clock, rate_hz=0, burst_count=0
-        )
-        self._rc_message = self.hs.config.ratelimiting.rc_message
-
-        # Check whether ratelimiting room admin message redaction is enabled
-        # by the presence of rate limits in the config
-        if self.hs.config.ratelimiting.rc_admin_redaction:
-            self.admin_redaction_ratelimiter: Optional[Ratelimiter] = Ratelimiter(
-                store=self.store,
-                clock=self.clock,
-                rate_hz=self.hs.config.ratelimiting.rc_admin_redaction.per_second,
-                burst_count=self.hs.config.ratelimiting.rc_admin_redaction.burst_count,
-            )
-        else:
-            self.admin_redaction_ratelimiter = None
-
-        self.server_name = hs.hostname
-
-        self.event_builder_factory = hs.get_event_builder_factory()
-
-    async def ratelimit(
-        self,
-        requester: Requester,
-        update: bool = True,
-        is_admin_redaction: bool = False,
-    ) -> None:
-        """Ratelimits requests.
-
-        Args:
-            requester
-            update: Whether to record that a request is being processed.
-                Set to False when doing multiple checks for one request (e.g.
-                to check up front if we would reject the request), and set to
-                True for the last call for a given request.
-            is_admin_redaction: Whether this is a room admin/moderator
-                redacting an event. If so then we may apply different
-                ratelimits depending on config.
-
-        Raises:
-            LimitExceededError if the request should be ratelimited
-        """
-        user_id = requester.user.to_string()
-
-        # The AS user itself is never rate limited.
-        app_service = self.store.get_app_service_by_user_id(user_id)
-        if app_service is not None:
-            return  # do not ratelimit app service senders
-
-        messages_per_second = self._rc_message.per_second
-        burst_count = self._rc_message.burst_count
-
-        # Check if there is a per user override in the DB.
-        override = await self.store.get_ratelimit_for_user(user_id)
-        if override:
-            # If overridden with a null Hz then ratelimiting has been entirely
-            # disabled for the user
-            if not override.messages_per_second:
-                return
-
-            messages_per_second = override.messages_per_second
-            burst_count = override.burst_count
-
-        if is_admin_redaction and self.admin_redaction_ratelimiter:
-            # If we have separate config for admin redactions, use a separate
-            # ratelimiter as to not have user_ids clash
-            await self.admin_redaction_ratelimiter.ratelimit(requester, update=update)
-        else:
-            # Override rate and burst count per-user
-            await self.request_ratelimiter.ratelimit(
-                requester,
-                rate_hz=messages_per_second,
-                burst_count=burst_count,
-                update=update,
-            )
diff --git a/synapse/handlers/admin.py b/synapse/handlers/admin.py
index bfa7f2c545..a53cd62d3c 100644
--- a/synapse/handlers/admin.py
+++ b/synapse/handlers/admin.py
@@ -21,18 +21,15 @@ from synapse.events import EventBase
 from synapse.types import JsonDict, RoomStreamToken, StateMap, UserID
 from synapse.visibility import filter_events_for_client
 
-from ._base import BaseHandler
-
 if TYPE_CHECKING:
     from synapse.server import HomeServer
 
 logger = logging.getLogger(__name__)
 
 
-class AdminHandler(BaseHandler):
+class AdminHandler:
     def __init__(self, hs: "HomeServer"):
-        super().__init__(hs)
-
+        self.store = hs.get_datastore()
         self.storage = hs.get_storage()
         self.state_store = self.storage.state
 
diff --git a/synapse/handlers/auth.py b/synapse/handlers/auth.py
index 2d0f3d566c..f4612a5b92 100644
--- a/synapse/handlers/auth.py
+++ b/synapse/handlers/auth.py
@@ -52,7 +52,6 @@ from synapse.api.errors import (
     UserDeactivatedError,
 )
 from synapse.api.ratelimiting import Ratelimiter
-from synapse.handlers._base import BaseHandler
 from synapse.handlers.ui_auth import (
     INTERACTIVE_AUTH_CHECKERS,
     UIAuthSessionDataConstants,
@@ -186,12 +185,13 @@ class LoginTokenAttributes:
     auth_provider_id = attr.ib(type=str)
 
 
-class AuthHandler(BaseHandler):
+class AuthHandler:
     SESSION_EXPIRE_MS = 48 * 60 * 60 * 1000
 
     def __init__(self, hs: "HomeServer"):
-        super().__init__(hs)
-
+        self.store = hs.get_datastore()
+        self.auth = hs.get_auth()
+        self.clock = hs.get_clock()
         self.checkers: Dict[str, UserInteractiveAuthChecker] = {}
         for auth_checker_class in INTERACTIVE_AUTH_CHECKERS:
             inst = auth_checker_class(hs)
diff --git a/synapse/handlers/deactivate_account.py b/synapse/handlers/deactivate_account.py
index 12bdca7445..e88c3c27ce 100644
--- a/synapse/handlers/deactivate_account.py
+++ b/synapse/handlers/deactivate_account.py
@@ -19,19 +19,17 @@ from synapse.api.errors import SynapseError
 from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.types import Requester, UserID, create_requester
 
-from ._base import BaseHandler
-
 if TYPE_CHECKING:
     from synapse.server import HomeServer
 
 logger = logging.getLogger(__name__)
 
 
-class DeactivateAccountHandler(BaseHandler):
+class DeactivateAccountHandler:
     """Handler which deals with deactivating user accounts."""
 
     def __init__(self, hs: "HomeServer"):
-        super().__init__(hs)
+        self.store = hs.get_datastore()
         self.hs = hs
         self._auth_handler = hs.get_auth_handler()
         self._device_handler = hs.get_device_handler()
diff --git a/synapse/handlers/device.py b/synapse/handlers/device.py
index 35334725d7..75e6019760 100644
--- a/synapse/handlers/device.py
+++ b/synapse/handlers/device.py
@@ -40,8 +40,6 @@ from synapse.util.caches.expiringcache import ExpiringCache
 from synapse.util.metrics import measure_func
 from synapse.util.retryutils import NotRetryingDestination
 
-from ._base import BaseHandler
-
 if TYPE_CHECKING:
     from synapse.server import HomeServer
 
@@ -50,14 +48,16 @@ logger = logging.getLogger(__name__)
 MAX_DEVICE_DISPLAY_NAME_LEN = 100
 
 
-class DeviceWorkerHandler(BaseHandler):
+class DeviceWorkerHandler:
     def __init__(self, hs: "HomeServer"):
-        super().__init__(hs)
-
+        self.clock = hs.get_clock()
         self.hs = hs
+        self.store = hs.get_datastore()
+        self.notifier = hs.get_notifier()
         self.state = hs.get_state_handler()
         self.state_store = hs.get_storage().state
         self._auth_handler = hs.get_auth_handler()
+        self.server_name = hs.hostname
 
     @trace
     async def get_devices_by_user(self, user_id: str) -> List[JsonDict]:
diff --git a/synapse/handlers/directory.py b/synapse/handlers/directory.py
index 9078781d5a..14ed7d9879 100644
--- a/synapse/handlers/directory.py
+++ b/synapse/handlers/directory.py
@@ -31,18 +31,16 @@ from synapse.appservice import ApplicationService
 from synapse.storage.databases.main.directory import RoomAliasMapping
 from synapse.types import JsonDict, Requester, RoomAlias, UserID, get_domain_from_id
 
-from ._base import BaseHandler
-
 if TYPE_CHECKING:
     from synapse.server import HomeServer
 
 logger = logging.getLogger(__name__)
 
 
-class DirectoryHandler(BaseHandler):
+class DirectoryHandler:
     def __init__(self, hs: "HomeServer"):
-        super().__init__(hs)
-
+        self.auth = hs.get_auth()
+        self.hs = hs
         self.state = hs.get_state_handler()
         self.appservice_handler = hs.get_application_service_handler()
         self.event_creation_handler = hs.get_event_creation_handler()
@@ -51,6 +49,7 @@ class DirectoryHandler(BaseHandler):
         self.enable_room_list_search = hs.config.roomdirectory.enable_room_list_search
         self.require_membership = hs.config.server.require_membership_for_aliases
         self.third_party_event_rules = hs.get_third_party_event_rules()
+        self.server_name = hs.hostname
 
         self.federation = hs.get_federation_client()
         hs.get_federation_registry().register_query_handler(
diff --git a/synapse/handlers/events.py b/synapse/handlers/events.py
index 4b3f037072..1f64534a8a 100644
--- a/synapse/handlers/events.py
+++ b/synapse/handlers/events.py
@@ -25,8 +25,6 @@ from synapse.streams.config import PaginationConfig
 from synapse.types import JsonDict, UserID
 from synapse.visibility import filter_events_for_client
 
-from ._base import BaseHandler
-
 if TYPE_CHECKING:
     from synapse.server import HomeServer
 
@@ -34,11 +32,11 @@ if TYPE_CHECKING:
 logger = logging.getLogger(__name__)
 
 
-class EventStreamHandler(BaseHandler):
+class EventStreamHandler:
     def __init__(self, hs: "HomeServer"):
-        super().__init__(hs)
-
+        self.store = hs.get_datastore()
         self.clock = hs.get_clock()
+        self.hs = hs
 
         self.notifier = hs.get_notifier()
         self.state = hs.get_state_handler()
@@ -138,9 +136,9 @@ class EventStreamHandler(BaseHandler):
             return chunk
 
 
-class EventHandler(BaseHandler):
+class EventHandler:
     def __init__(self, hs: "HomeServer"):
-        super().__init__(hs)
+        self.store = hs.get_datastore()
         self.storage = hs.get_storage()
 
     async def get_event(
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index 043ca4a224..3e341bd287 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -53,7 +53,6 @@ from synapse.events import EventBase
 from synapse.events.snapshot import EventContext
 from synapse.events.validator import EventValidator
 from synapse.federation.federation_client import InvalidResponseError
-from synapse.handlers._base import BaseHandler
 from synapse.http.servlet import assert_params_in_dict
 from synapse.logging.context import (
     make_deferred_yieldable,
@@ -78,15 +77,13 @@ if TYPE_CHECKING:
 logger = logging.getLogger(__name__)
 
 
-class FederationHandler(BaseHandler):
+class FederationHandler:
     """Handles general incoming federation requests
 
     Incoming events are *not* handled here, for which see FederationEventHandler.
     """
 
     def __init__(self, hs: "HomeServer"):
-        super().__init__(hs)
-
         self.hs = hs
 
         self.store = hs.get_datastore()
@@ -99,6 +96,7 @@ class FederationHandler(BaseHandler):
         self.is_mine_id = hs.is_mine_id
         self.spam_checker = hs.get_spam_checker()
         self.event_creation_handler = hs.get_event_creation_handler()
+        self.event_builder_factory = hs.get_event_builder_factory()
         self._event_auth_handler = hs.get_event_auth_handler()
         self._server_notices_mxid = hs.config.servernotices.server_notices_mxid
         self.config = hs.config
diff --git a/synapse/handlers/identity.py b/synapse/handlers/identity.py
index c881475c25..9c319b5383 100644
--- a/synapse/handlers/identity.py
+++ b/synapse/handlers/identity.py
@@ -39,8 +39,6 @@ from synapse.util.stringutils import (
     valid_id_server_location,
 )
 
-from ._base import BaseHandler
-
 if TYPE_CHECKING:
     from synapse.server import HomeServer
 
@@ -49,10 +47,9 @@ logger = logging.getLogger(__name__)
 id_server_scheme = "https://"
 
 
-class IdentityHandler(BaseHandler):
+class IdentityHandler:
     def __init__(self, hs: "HomeServer"):
-        super().__init__(hs)
-
+        self.store = hs.get_datastore()
         # An HTTP client for contacting trusted URLs.
         self.http_client = SimpleHttpClient(hs)
         # An HTTP client for contacting identity servers specified by clients.
diff --git a/synapse/handlers/initial_sync.py b/synapse/handlers/initial_sync.py
index 9ad39a65d8..d4e4556155 100644
--- a/synapse/handlers/initial_sync.py
+++ b/synapse/handlers/initial_sync.py
@@ -31,8 +31,6 @@ from synapse.util.async_helpers import concurrently_execute
 from synapse.util.caches.response_cache import ResponseCache
 from synapse.visibility import filter_events_for_client
 
-from ._base import BaseHandler
-
 if TYPE_CHECKING:
     from synapse.server import HomeServer
 
@@ -40,9 +38,11 @@ if TYPE_CHECKING:
 logger = logging.getLogger(__name__)
 
 
-class InitialSyncHandler(BaseHandler):
+class InitialSyncHandler:
     def __init__(self, hs: "HomeServer"):
-        super().__init__(hs)
+        self.store = hs.get_datastore()
+        self.auth = hs.get_auth()
+        self.state_handler = hs.get_state_handler()
         self.hs = hs
         self.state = hs.get_state_handler()
         self.clock = hs.get_clock()
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index ccd7827207..4de9f4b828 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -62,8 +62,6 @@ from synapse.util.caches.expiringcache import ExpiringCache
 from synapse.util.metrics import measure_func
 from synapse.visibility import filter_events_for_client
 
-from ._base import BaseHandler
-
 if TYPE_CHECKING:
     from synapse.events.third_party_rules import ThirdPartyEventRules
     from synapse.server import HomeServer
@@ -433,8 +431,7 @@ class EventCreationHandler:
 
         self.send_event = ReplicationSendEventRestServlet.make_client(hs)
 
-        # This is only used to get at ratelimit function
-        self.base_handler = BaseHandler(hs)
+        self.request_ratelimiter = hs.get_request_ratelimiter()
 
         # We arbitrarily limit concurrent event creation for a room to 5.
         # This is to stop us from diverging history *too* much.
@@ -1322,7 +1319,7 @@ class EventCreationHandler:
                     original_event and event.sender != original_event.sender
                 )
 
-            await self.base_handler.ratelimit(
+            await self.request_ratelimiter.ratelimit(
                 requester, is_admin_redaction=is_admin_redaction
             )
 
diff --git a/synapse/handlers/profile.py b/synapse/handlers/profile.py
index 2e19706c69..e6c3cf585b 100644
--- a/synapse/handlers/profile.py
+++ b/synapse/handlers/profile.py
@@ -32,8 +32,6 @@ from synapse.types import (
     get_domain_from_id,
 )
 
-from ._base import BaseHandler
-
 if TYPE_CHECKING:
     from synapse.server import HomeServer
 
@@ -43,7 +41,7 @@ MAX_DISPLAYNAME_LEN = 256
 MAX_AVATAR_URL_LEN = 1000
 
 
-class ProfileHandler(BaseHandler):
+class ProfileHandler:
     """Handles fetching and updating user profile information.
 
     ProfileHandler can be instantiated directly on workers and will
@@ -54,7 +52,9 @@ class ProfileHandler(BaseHandler):
     PROFILE_UPDATE_EVERY_MS = 24 * 60 * 60 * 1000
 
     def __init__(self, hs: "HomeServer"):
-        super().__init__(hs)
+        self.store = hs.get_datastore()
+        self.clock = hs.get_clock()
+        self.hs = hs
 
         self.federation = hs.get_federation_client()
         hs.get_federation_registry().register_query_handler(
@@ -62,6 +62,7 @@ class ProfileHandler(BaseHandler):
         )
 
         self.user_directory_handler = hs.get_user_directory_handler()
+        self.request_ratelimiter = hs.get_request_ratelimiter()
 
         if hs.config.worker.run_background_tasks:
             self.clock.looping_call(
@@ -346,7 +347,7 @@ class ProfileHandler(BaseHandler):
         if not self.hs.is_mine(target_user):
             return
 
-        await self.ratelimit(requester)
+        await self.request_ratelimiter.ratelimit(requester)
 
         # Do not actually update the room state for shadow-banned users.
         if requester.shadow_banned:
diff --git a/synapse/handlers/read_marker.py b/synapse/handlers/read_marker.py
index bd8160e7ed..58593e570e 100644
--- a/synapse/handlers/read_marker.py
+++ b/synapse/handlers/read_marker.py
@@ -17,17 +17,14 @@ from typing import TYPE_CHECKING
 
 from synapse.util.async_helpers import Linearizer
 
-from ._base import BaseHandler
-
 if TYPE_CHECKING:
     from synapse.server import HomeServer
 
 logger = logging.getLogger(__name__)
 
 
-class ReadMarkerHandler(BaseHandler):
+class ReadMarkerHandler:
     def __init__(self, hs: "HomeServer"):
-        super().__init__(hs)
         self.server_name = hs.config.server.server_name
         self.store = hs.get_datastore()
         self.account_data_handler = hs.get_account_data_handler()
diff --git a/synapse/handlers/receipts.py b/synapse/handlers/receipts.py
index f21f33ada2..374e961e3b 100644
--- a/synapse/handlers/receipts.py
+++ b/synapse/handlers/receipts.py
@@ -16,7 +16,6 @@ from typing import TYPE_CHECKING, Iterable, List, Optional, Tuple
 
 from synapse.api.constants import ReadReceiptEventFields
 from synapse.appservice import ApplicationService
-from synapse.handlers._base import BaseHandler
 from synapse.streams import EventSource
 from synapse.types import JsonDict, ReadReceipt, UserID, get_domain_from_id
 
@@ -26,10 +25,9 @@ if TYPE_CHECKING:
 logger = logging.getLogger(__name__)
 
 
-class ReceiptsHandler(BaseHandler):
+class ReceiptsHandler:
     def __init__(self, hs: "HomeServer"):
-        super().__init__(hs)
-
+        self.notifier = hs.get_notifier()
         self.server_name = hs.config.server.server_name
         self.store = hs.get_datastore()
         self.event_auth_handler = hs.get_event_auth_handler()
diff --git a/synapse/handlers/register.py b/synapse/handlers/register.py
index 441af7a848..a0e6a01775 100644
--- a/synapse/handlers/register.py
+++ b/synapse/handlers/register.py
@@ -41,8 +41,6 @@ from synapse.spam_checker_api import RegistrationBehaviour
 from synapse.storage.state import StateFilter
 from synapse.types import RoomAlias, UserID, create_requester
 
-from ._base import BaseHandler
-
 if TYPE_CHECKING:
     from synapse.server import HomeServer
 
@@ -85,9 +83,10 @@ class LoginDict(TypedDict):
     refresh_token: Optional[str]
 
 
-class RegistrationHandler(BaseHandler):
+class RegistrationHandler:
     def __init__(self, hs: "HomeServer"):
-        super().__init__(hs)
+        self.store = hs.get_datastore()
+        self.clock = hs.get_clock()
         self.hs = hs
         self.auth = hs.get_auth()
         self._auth_handler = hs.get_auth_handler()
@@ -515,7 +514,7 @@ class RegistrationHandler(BaseHandler):
                 # we don't have a local user in the room to craft up an invite with.
                 requires_invite = await self.store.is_host_joined(
                     room_id,
-                    self.server_name,
+                    self._server_name,
                 )
 
                 if requires_invite:
diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index d40dbd761d..7072bca1fc 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -76,8 +76,6 @@ from synapse.util.caches.response_cache import ResponseCache
 from synapse.util.stringutils import parse_and_validate_server_name
 from synapse.visibility import filter_events_for_client
 
-from ._base import BaseHandler
-
 if TYPE_CHECKING:
     from synapse.server import HomeServer
 
@@ -88,15 +86,18 @@ id_server_scheme = "https://"
 FIVE_MINUTES_IN_MS = 5 * 60 * 1000
 
 
-class RoomCreationHandler(BaseHandler):
+class RoomCreationHandler:
     def __init__(self, hs: "HomeServer"):
-        super().__init__(hs)
-
+        self.store = hs.get_datastore()
+        self.auth = hs.get_auth()
+        self.clock = hs.get_clock()
+        self.hs = hs
         self.spam_checker = hs.get_spam_checker()
         self.event_creation_handler = hs.get_event_creation_handler()
         self.room_member_handler = hs.get_room_member_handler()
         self._event_auth_handler = hs.get_event_auth_handler()
         self.config = hs.config
+        self.request_ratelimiter = hs.get_request_ratelimiter()
 
         # Room state based off defined presets
         self._presets_dict: Dict[str, Dict[str, Any]] = {
@@ -162,7 +163,7 @@ class RoomCreationHandler(BaseHandler):
         Raises:
             ShadowBanError if the requester is shadow-banned.
         """
-        await self.ratelimit(requester)
+        await self.request_ratelimiter.ratelimit(requester)
 
         user_id = requester.user.to_string()
 
@@ -665,7 +666,7 @@ class RoomCreationHandler(BaseHandler):
             raise SynapseError(403, "You are not permitted to create rooms")
 
         if ratelimit:
-            await self.ratelimit(requester)
+            await self.request_ratelimiter.ratelimit(requester)
 
         room_version_id = config.get(
             "room_version", self.config.server.default_room_version.identifier
diff --git a/synapse/handlers/room_list.py b/synapse/handlers/room_list.py
index c3d4199ed1..ba7a14d651 100644
--- a/synapse/handlers/room_list.py
+++ b/synapse/handlers/room_list.py
@@ -36,8 +36,6 @@ from synapse.types import JsonDict, ThirdPartyInstanceID
 from synapse.util.caches.descriptors import _CacheContext, cached
 from synapse.util.caches.response_cache import ResponseCache
 
-from ._base import BaseHandler
-
 if TYPE_CHECKING:
     from synapse.server import HomeServer
 
@@ -49,9 +47,10 @@ REMOTE_ROOM_LIST_POLL_INTERVAL = 60 * 1000
 EMPTY_THIRD_PARTY_ID = ThirdPartyInstanceID(None, None)
 
 
-class RoomListHandler(BaseHandler):
+class RoomListHandler:
     def __init__(self, hs: "HomeServer"):
-        super().__init__(hs)
+        self.store = hs.get_datastore()
+        self.hs = hs
         self.enable_room_list_search = hs.config.roomdirectory.enable_room_list_search
         self.response_cache: ResponseCache[
             Tuple[Optional[int], Optional[str], Optional[ThirdPartyInstanceID]]
diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py
index eef337feeb..74e6c7eca6 100644
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -51,8 +51,6 @@ from synapse.types import (
 from synapse.util.async_helpers import Linearizer
 from synapse.util.distributor import user_left_room
 
-from ._base import BaseHandler
-
 if TYPE_CHECKING:
     from synapse.server import HomeServer
 
@@ -118,9 +116,7 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
             burst_count=hs.config.ratelimiting.rc_invites_per_user.burst_count,
         )
 
-        # This is only used to get at the ratelimit function. It's fine there are
-        # multiple of these as it doesn't store state.
-        self.base_handler = BaseHandler(hs)
+        self.request_ratelimiter = hs.get_request_ratelimiter()
 
     @abc.abstractmethod
     async def _remote_join(
@@ -1275,7 +1271,7 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
 
         # We need to rate limit *before* we send out any 3PID invites, so we
         # can't just rely on the standard ratelimiting of events.
-        await self.base_handler.ratelimit(requester)
+        await self.request_ratelimiter.ratelimit(requester)
 
         can_invite = await self.third_party_event_rules.check_threepid_can_be_invited(
             medium, address, room_id
diff --git a/synapse/handlers/saml.py b/synapse/handlers/saml.py
index 2fed9f377a..727d75a50c 100644
--- a/synapse/handlers/saml.py
+++ b/synapse/handlers/saml.py
@@ -22,7 +22,6 @@ from saml2.client import Saml2Client
 
 from synapse.api.errors import SynapseError
 from synapse.config import ConfigError
-from synapse.handlers._base import BaseHandler
 from synapse.handlers.sso import MappingException, UserAttributes
 from synapse.http.servlet import parse_string
 from synapse.http.site import SynapseRequest
@@ -51,9 +50,11 @@ class Saml2SessionData:
     ui_auth_session_id: Optional[str] = None
 
 
-class SamlHandler(BaseHandler):
+class SamlHandler:
     def __init__(self, hs: "HomeServer"):
-        super().__init__(hs)
+        self.store = hs.get_datastore()
+        self.clock = hs.get_clock()
+        self.server_name = hs.hostname
         self._saml_client = Saml2Client(hs.config.saml2.saml2_sp_config)
         self._saml_idp_entityid = hs.config.saml2.saml2_idp_entityid
 
diff --git a/synapse/handlers/search.py b/synapse/handlers/search.py
index 6d3333ee00..a3ffa26be8 100644
--- a/synapse/handlers/search.py
+++ b/synapse/handlers/search.py
@@ -26,17 +26,18 @@ from synapse.storage.state import StateFilter
 from synapse.types import JsonDict, UserID
 from synapse.visibility import filter_events_for_client
 
-from ._base import BaseHandler
-
 if TYPE_CHECKING:
     from synapse.server import HomeServer
 
 logger = logging.getLogger(__name__)
 
 
-class SearchHandler(BaseHandler):
+class SearchHandler:
     def __init__(self, hs: "HomeServer"):
-        super().__init__(hs)
+        self.store = hs.get_datastore()
+        self.state_handler = hs.get_state_handler()
+        self.clock = hs.get_clock()
+        self.hs = hs
         self._event_serializer = hs.get_event_client_serializer()
         self.storage = hs.get_storage()
         self.state_store = self.storage.state
diff --git a/synapse/handlers/set_password.py b/synapse/handlers/set_password.py
index a63fac8283..706ad72761 100644
--- a/synapse/handlers/set_password.py
+++ b/synapse/handlers/set_password.py
@@ -17,19 +17,17 @@ from typing import TYPE_CHECKING, Optional
 from synapse.api.errors import Codes, StoreError, SynapseError
 from synapse.types import Requester
 
-from ._base import BaseHandler
-
 if TYPE_CHECKING:
     from synapse.server import HomeServer
 
 logger = logging.getLogger(__name__)
 
 
-class SetPasswordHandler(BaseHandler):
+class SetPasswordHandler:
     """Handler which deals with changing user account passwords"""
 
     def __init__(self, hs: "HomeServer"):
-        super().__init__(hs)
+        self.store = hs.get_datastore()
         self._auth_handler = hs.get_auth_handler()
         self._device_handler = hs.get_device_handler()
 
diff --git a/synapse/server.py b/synapse/server.py
index 637eb15b78..0783df41d4 100644
--- a/synapse/server.py
+++ b/synapse/server.py
@@ -39,7 +39,7 @@ from twisted.web.resource import IResource
 
 from synapse.api.auth import Auth
 from synapse.api.filtering import Filtering
-from synapse.api.ratelimiting import Ratelimiter
+from synapse.api.ratelimiting import Ratelimiter, RequestRatelimiter
 from synapse.appservice.api import ApplicationServiceApi
 from synapse.appservice.scheduler import ApplicationServiceScheduler
 from synapse.config.homeserver import HomeServerConfig
@@ -816,3 +816,12 @@ class HomeServer(metaclass=abc.ABCMeta):
     def should_send_federation(self) -> bool:
         "Should this server be sending federation traffic directly?"
         return self.config.worker.send_federation
+
+    @cache_in_self
+    def get_request_ratelimiter(self) -> RequestRatelimiter:
+        return RequestRatelimiter(
+            self.get_datastore(),
+            self.get_clock(),
+            self.config.ratelimiting.rc_message,
+            self.config.ratelimiting.rc_admin_redaction,
+        )