Move Spam Checker callbacks to a dedicated file

The next commit updates all the uses of the spam checker (of which there
are quite a few...), hence breaking up the commits.

synapse/module_api/__init__.py

@@ -44,20 +44,6 @@ from synapse.events.presence_router import (
     GET_USERS_FOR_STATES_CALLBACK,
     PresenceRouter,
 )
-from synapse.events.spamcheck import (
-    CHECK_EVENT_FOR_SPAM_CALLBACK,
-    CHECK_MEDIA_FILE_FOR_SPAM_CALLBACK,
-    CHECK_REGISTRATION_FOR_SPAM_CALLBACK,
-    CHECK_USERNAME_FOR_SPAM_CALLBACK,
-    SHOULD_DROP_FEDERATED_EVENT_CALLBACK,
-    USER_MAY_CREATE_ROOM_ALIAS_CALLBACK,
-    USER_MAY_CREATE_ROOM_CALLBACK,
-    USER_MAY_INVITE_CALLBACK,
-    USER_MAY_JOIN_ROOM_CALLBACK,
-    USER_MAY_PUBLISH_ROOM_CALLBACK,
-    USER_MAY_SEND_3PID_INVITE_CALLBACK,
-    SpamChecker,
-)
 from synapse.events.third_party_rules import (
     CHECK_CAN_DEACTIVATE_USER_CALLBACK,
     CHECK_CAN_SHUTDOWN_ROOM_CALLBACK,
@@ -103,6 +89,20 @@ from synapse.module_api.callbacks.account_validity_callbacks import (
     ON_LEGACY_SEND_MAIL_CALLBACK,
     ON_USER_REGISTRATION_CALLBACK,
 )
+from synapse.module_api.callbacks.spamchecker_callbacks import (
+    CHECK_EVENT_FOR_SPAM_CALLBACK,
+    CHECK_MEDIA_FILE_FOR_SPAM_CALLBACK,
+    CHECK_REGISTRATION_FOR_SPAM_CALLBACK,
+    CHECK_USERNAME_FOR_SPAM_CALLBACK,
+    SHOULD_DROP_FEDERATED_EVENT_CALLBACK,
+    USER_MAY_CREATE_ROOM_ALIAS_CALLBACK,
+    USER_MAY_CREATE_ROOM_CALLBACK,
+    USER_MAY_INVITE_CALLBACK,
+    USER_MAY_JOIN_ROOM_CALLBACK,
+    USER_MAY_PUBLISH_ROOM_CALLBACK,
+    USER_MAY_SEND_3PID_INVITE_CALLBACK,
+    SpamCheckerModuleApiCallbacks,
+)
 from synapse.rest.client.login import LoginResponse
 from synapse.storage import DataStore
 from synapse.storage.background_updates import (
@@ -145,7 +145,7 @@ are loaded into Synapse.
 """
 
 PRESENCE_ALL_USERS = PresenceRouter.ALL_USERS
-NOT_SPAM = SpamChecker.NOT_SPAM
+NOT_SPAM = SpamCheckerModuleApiCallbacks.NOT_SPAM
 
 __all__ = [
     "errors",
@@ -269,7 +269,6 @@ class ModuleApi:
         self._public_room_list_manager = PublicRoomListManager(hs)
         self._account_data_manager = AccountDataManager(hs)
 
-        self._spam_checker = hs.get_spam_checker()
         self._third_party_event_rules = hs.get_third_party_event_rules()
         self._password_auth_provider = hs.get_password_auth_provider()
         self._presence_router = hs.get_presence_router()
@@ -303,7 +302,7 @@ class ModuleApi:
 
         Added in Synapse v1.37.0.
         """
-        return self._spam_checker.register_callbacks(
+        return self._callbacks.spam_checker.register_callbacks(
             check_event_for_spam=check_event_for_spam,
             should_drop_federated_event=should_drop_federated_event,
             user_may_join_room=user_may_join_room,

synapse/module_api/callbacks/__init__.py

@@ -12,7 +12,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from synapse.server import HomeServer
+
 from .account_validity_callbacks import AccountValidityModuleApiCallbacks
+from .spamchecker_callbacks import SpamCheckerModuleApiCallbacks
 
 __all__ = [
     "AccountValidityModuleApiCallbacks",
@@ -21,5 +27,6 @@ __all__ = [
 
 
 class ModuleApiCallbacks:
-    def __init__(self) -> None:
+    def __init__(self, hs: "HomeServer") -> None:
         self.account_validity = AccountValidityModuleApiCallbacks()
+        self.spam_checker = SpamCheckerModuleApiCallbacks(hs)

synapse/module_api/callbacks/spamchecker_callbacks.py

@@ -286,11 +286,10 @@ def load_legacy_spam_checkers(hs: "synapse.server.HomeServer") -> None:
         api.register_spam_checker_callbacks(**hooks)
 
 
-class SpamChecker:
+class SpamCheckerModuleApiCallbacks:
     NOT_SPAM: Literal["NOT_SPAM"] = "NOT_SPAM"
 
     def __init__(self, hs: "synapse.server.HomeServer") -> None:
-        self.hs = hs
         self.clock = hs.get_clock()
 
         self._check_event_for_spam_callbacks: List[CHECK_EVENT_FOR_SPAM_CALLBACK] = []

synapse/server.py

@@ -40,7 +40,6 @@ from synapse.crypto.context_factory import RegularPolicyForHTTPS
 from synapse.crypto.keyring import Keyring
 from synapse.events.builder import EventBuilderFactory
 from synapse.events.presence_router import PresenceRouter
-from synapse.events.spamcheck import SpamChecker
 from synapse.events.third_party_rules import ThirdPartyEventRules
 from synapse.events.utils import EventClientSerializer
 from synapse.federation.federation_client import FederationClient
@@ -666,10 +665,6 @@ class HomeServer(metaclass=abc.ABCMeta):
     def get_stats_handler(self) -> StatsHandler:
         return StatsHandler(self)
 
-    @cache_in_self
-    def get_spam_checker(self) -> SpamChecker:
-        return SpamChecker(self)
-
     @cache_in_self
     def get_third_party_event_rules(self) -> ThirdPartyEventRules:
         return ThirdPartyEventRules(self)
@@ -782,7 +777,7 @@ class HomeServer(metaclass=abc.ABCMeta):
 
     @cache_in_self
     def get_module_api_callbacks(self) -> ModuleApiCallbacks:
-        return ModuleApiCallbacks()
+        return ModuleApiCallbacks(self)
 
     @cache_in_self
     def get_account_data_handler(self) -> AccountDataHandler: