Add media repository callbacks to module API to control media upload size (#18457)

Adds new callbacks for media related functionality:

- `get_media_config_for_user`
- `is_user_allowed_to_upload_media_of_size`

synapse/module_api/__init__.py

@@ -90,6 +90,10 @@ from synapse.module_api.callbacks.account_validity_callbacks import (
     ON_USER_LOGIN_CALLBACK,
     ON_USER_REGISTRATION_CALLBACK,
 )
+from synapse.module_api.callbacks.media_repository_callbacks import (
+    GET_MEDIA_CONFIG_FOR_USER_CALLBACK,
+    IS_USER_ALLOWED_TO_UPLOAD_MEDIA_OF_SIZE_CALLBACK,
+)
 from synapse.module_api.callbacks.spamchecker_callbacks import (
     CHECK_EVENT_FOR_SPAM_CALLBACK,
     CHECK_LOGIN_FOR_SPAM_CALLBACK,
@@ -360,6 +364,22 @@ class ModuleApi:
             on_legacy_admin_request=on_legacy_admin_request,
         )
 
+    def register_media_repository_callbacks(
+        self,
+        *,
+        get_media_config_for_user: Optional[GET_MEDIA_CONFIG_FOR_USER_CALLBACK] = None,
+        is_user_allowed_to_upload_media_of_size: Optional[
+            IS_USER_ALLOWED_TO_UPLOAD_MEDIA_OF_SIZE_CALLBACK
+        ] = None,
+    ) -> None:
+        """Registers callbacks for media repository capabilities.
+        Added in Synapse v1.x.x.
+        """
+        return self._callbacks.media_repository.register_callbacks(
+            get_media_config_for_user=get_media_config_for_user,
+            is_user_allowed_to_upload_media_of_size=is_user_allowed_to_upload_media_of_size,
+        )
+
     def register_third_party_rules_callbacks(
         self,
         *,

synapse/module_api/callbacks/__init__.py

@@ -27,6 +27,9 @@ if TYPE_CHECKING:
 from synapse.module_api.callbacks.account_validity_callbacks import (
     AccountValidityModuleApiCallbacks,
 )
+from synapse.module_api.callbacks.media_repository_callbacks import (
+    MediaRepositoryModuleApiCallbacks,
+)
 from synapse.module_api.callbacks.spamchecker_callbacks import (
     SpamCheckerModuleApiCallbacks,
 )
@@ -38,5 +41,6 @@ from synapse.module_api.callbacks.third_party_event_rules_callbacks import (
 class ModuleApiCallbacks:
     def __init__(self, hs: "HomeServer") -> None:
         self.account_validity = AccountValidityModuleApiCallbacks()
+        self.media_repository = MediaRepositoryModuleApiCallbacks(hs)
         self.spam_checker = SpamCheckerModuleApiCallbacks(hs)
         self.third_party_event_rules = ThirdPartyEventRulesModuleApiCallbacks(hs)

synapse/module_api/callbacks/media_repository_callbacks.py

@@ -0,0 +1,76 @@
+#
+# This file is licensed under the Affero General Public License (AGPL) version 3.
+#
+# Copyright (C) 2025 New Vector, Ltd
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# See the GNU Affero General Public License for more details:
+# <https://www.gnu.org/licenses/agpl-3.0.html>.
+#
+
+import logging
+from typing import TYPE_CHECKING, Awaitable, Callable, List, Optional
+
+from synapse.types import JsonDict
+from synapse.util.async_helpers import delay_cancellation
+from synapse.util.metrics import Measure
+
+if TYPE_CHECKING:
+    from synapse.server import HomeServer
+
+logger = logging.getLogger(__name__)
+
+GET_MEDIA_CONFIG_FOR_USER_CALLBACK = Callable[[str], Awaitable[Optional[JsonDict]]]
+
+IS_USER_ALLOWED_TO_UPLOAD_MEDIA_OF_SIZE_CALLBACK = Callable[[str, int], Awaitable[bool]]
+
+
+class MediaRepositoryModuleApiCallbacks:
+    def __init__(self, hs: "HomeServer") -> None:
+        self.clock = hs.get_clock()
+        self._get_media_config_for_user_callbacks: List[
+            GET_MEDIA_CONFIG_FOR_USER_CALLBACK
+        ] = []
+        self._is_user_allowed_to_upload_media_of_size_callbacks: List[
+            IS_USER_ALLOWED_TO_UPLOAD_MEDIA_OF_SIZE_CALLBACK
+        ] = []
+
+    def register_callbacks(
+        self,
+        get_media_config_for_user: Optional[GET_MEDIA_CONFIG_FOR_USER_CALLBACK] = None,
+        is_user_allowed_to_upload_media_of_size: Optional[
+            IS_USER_ALLOWED_TO_UPLOAD_MEDIA_OF_SIZE_CALLBACK
+        ] = None,
+    ) -> None:
+        """Register callbacks from module for each hook."""
+        if get_media_config_for_user is not None:
+            self._get_media_config_for_user_callbacks.append(get_media_config_for_user)
+
+        if is_user_allowed_to_upload_media_of_size is not None:
+            self._is_user_allowed_to_upload_media_of_size_callbacks.append(
+                is_user_allowed_to_upload_media_of_size
+            )
+
+    async def get_media_config_for_user(self, user_id: str) -> Optional[JsonDict]:
+        for callback in self._get_media_config_for_user_callbacks:
+            with Measure(self.clock, f"{callback.__module__}.{callback.__qualname__}"):
+                res: Optional[JsonDict] = await delay_cancellation(callback(user_id))
+            if res:
+                return res
+
+        return None
+
+    async def is_user_allowed_to_upload_media_of_size(
+        self, user_id: str, size: int
+    ) -> bool:
+        for callback in self._is_user_allowed_to_upload_media_of_size_callbacks:
+            with Measure(self.clock, f"{callback.__module__}.{callback.__qualname__}"):
+                res: bool = await delay_cancellation(callback(user_id, size))
+            if not res:
+                return res
+
+        return True