From bfd6ddf2c00b4e67ea1a59420d39f3662013e34a Mon Sep 17 00:00:00 2001
From: Patrick Cloke <patrickc@matrix.org>
Date: Thu, 1 Dec 2022 12:23:31 -0500
Subject: [PATCH] Unknown endpoints for /media should return JSON responses.

This is a generalization of the previous commit since /media endpoints
are routed to via Twisted's standard Resource routing, not via
servlet routing.
---
 synapse/http/server.py                    | 17 +++++++++++++++
 synapse/rest/media/v1/media_repository.py |  4 ++--
 synapse/util/httpresourcetree.py          | 25 ++---------------------
 3 files changed, 21 insertions(+), 25 deletions(-)

diff --git a/synapse/http/server.py b/synapse/http/server.py
index 2f2431cc7c5a..9314454af106 100644
--- a/synapse/http/server.py
+++ b/synapse/http/server.py
@@ -570,6 +570,23 @@ def render_GET(self, request: Request) -> bytes:
         return super().render_GET(request)
 
 
+class UnrecognizedRequestResource(resource.Resource):
+    """
+    Similar to twisted.web.resource.NoResource, but returns a JSON 404 with an
+    errcode of M_UNRECOGNIZED.
+    """
+
+    def render(self, request: SynapseRequest) -> int:
+        f = failure.Failure(UnrecognizedRequestError(code=404))
+        return_json_error(f, request, None)
+        # A response has already been sent but Twisted requires either NOT_DONE_YET
+        # or the response bytes as a return value.
+        return NOT_DONE_YET
+
+    def getChild(self, name: str, request: Request) -> resource.Resource:
+        return self
+
+
 class RootRedirect(resource.Resource):
     """Redirects the root '/' path to another path."""
 
diff --git a/synapse/rest/media/v1/media_repository.py b/synapse/rest/media/v1/media_repository.py
index 40b0d39eb239..c70e1837afd0 100644
--- a/synapse/rest/media/v1/media_repository.py
+++ b/synapse/rest/media/v1/media_repository.py
@@ -24,7 +24,6 @@
 import twisted.internet.error
 import twisted.web.http
 from twisted.internet.defer import Deferred
-from twisted.web.resource import Resource
 
 from synapse.api.errors import (
     FederationDeniedError,
@@ -35,6 +34,7 @@
 )
 from synapse.config._base import ConfigError
 from synapse.config.repository import ThumbnailRequirement
+from synapse.http.server import UnrecognizedRequestResource
 from synapse.http.site import SynapseRequest
 from synapse.logging.context import defer_to_thread
 from synapse.metrics.background_process_metrics import run_as_background_process
@@ -1046,7 +1046,7 @@ async def _remove_local_media_from_disk(
         return removed_media, len(removed_media)
 
 
-class MediaRepositoryResource(Resource):
+class MediaRepositoryResource(UnrecognizedRequestResource):
     """File uploading and downloading.
 
     Uploads are POSTed to a resource which returns a token which is used to GET
diff --git a/synapse/util/httpresourcetree.py b/synapse/util/httpresourcetree.py
index f06011aac164..39fab4fe067e 100644
--- a/synapse/util/httpresourcetree.py
+++ b/synapse/util/httpresourcetree.py
@@ -15,34 +15,13 @@
 import logging
 from typing import Dict
 
-from twisted.python import failure
 from twisted.web.resource import Resource
-from twisted.web.server import NOT_DONE_YET, Request
 
-from synapse.api.errors import UnrecognizedRequestError
-from synapse.http.server import return_json_error
-from synapse.http.site import SynapseRequest
+from synapse.http.server import UnrecognizedRequestResource
 
 logger = logging.getLogger(__name__)
 
 
-class _UnrecognizedRequestResource(Resource):
-    """
-    Similar to twisted.web.resource.NoResource, but returns a JSON 404 with an
-    errcode of M_UNRECOGNIZED.
-    """
-
-    def render(self, request: SynapseRequest) -> int:
-        f = failure.Failure(UnrecognizedRequestError(code=404))
-        return_json_error(f, request, None)
-        # A response has already been sent but Twisted requires either NOT_DONE_YET
-        # or the response bytes as a return value.
-        return NOT_DONE_YET
-
-    def getChild(self, name: str, request: Request) -> Resource:
-        return self
-
-
 def create_resource_tree(
     desired_tree: Dict[str, Resource], root_resource: Resource
 ) -> Resource:
@@ -72,7 +51,7 @@ def create_resource_tree(
         for path_seg in full_path.split(b"/")[1:-1]:
             if path_seg not in last_resource.listNames():
                 # resource doesn't exist, so make a "dummy resource"
-                child_resource: Resource = _UnrecognizedRequestResource()
+                child_resource: Resource = UnrecognizedRequestResource()
                 last_resource.putChild(path_seg, child_resource)
                 res_id = _resource_id(last_resource, path_seg)
                 resource_mappings[res_id] = child_resource