Return JSON errors for unknown resources under /matrix/client. (#11602)

Instead of returning 404 errors with HTML bodies when an unknown
prefix was requested (e.g. /matrix/client/v1 before Synapse v1.49.0).

changelog.d/11602.bugfix

@@ -0,0 +1 @@
+Fix a long-standing bug that some unknown endpoints would return HTML error pages instead of JSON `M_UNRECOGNIZED` errors.

synapse/app/homeserver.py

@@ -27,6 +27,7 @@
 import synapse.config.logger
 from synapse import events
 from synapse.api.urls import (
+ CLIENT_API_PREFIX,
  FEDERATION_PREFIX,
  LEGACY_MEDIA_PREFIX,
  MEDIA_R0_PREFIX,
@@ -192,13 +193,7 @@ def _configure_named_resource(
 
  resources.update(
  {
- "/_matrix/client/api/v1": client_resource,
- "/_matrix/client/r0": client_resource,
- "/_matrix/client/v1": client_resource,
- "/_matrix/client/v3": client_resource,
- "/_matrix/client/unstable": client_resource,
- "/_matrix/client/v2_alpha": client_resource,
- "/_matrix/client/versions": client_resource,
+ CLIENT_API_PREFIX: client_resource,
  "/.well-known": well_known_resource(self),
  "/_synapse/admin": AdminRestResource(self),
  **build_synapse_client_resource_tree(self),

synapse/http/server.py

@@ -530,7 +530,7 @@ class RootRedirect(resource.Resource):
  """Redirects the root '/' path to another path."""
 
  def __init__(self, path: str):
- resource.Resource.__init__(self)
+ super().__init__()
  self.url = path
 
  def render_GET(self, request: Request) -> bytes:
@@ -539,7 +539,7 @@ def render_GET(self, request: Request) -> bytes:
  def getChild(self, name: str, request: Request) -> resource.Resource:
  if len(name) == 0:
  return self # select ourselves as the child to render
- return resource.Resource.getChild(self, name, request)
+ return super().getChild(name, request)
 
 
 class OptionsResource(resource.Resource):
@@ -556,7 +556,7 @@ def render_OPTIONS(self, request: Request) -> bytes:
  def getChildWithDefault(self, path: str, request: Request) -> resource.Resource:
  if request.method == b"OPTIONS":
  return self # select ourselves as the child to render
- return resource.Resource.getChildWithDefault(self, path, request)
+ return super().getChildWithDefault(path, request)
 
 
 class RootOptionsRedirectResource(OptionsResource, RootRedirect):