1 files changed, 12 insertions, 4 deletions
diff --git a/synapse/api/errors.py b/synapse/api/errors.py
index 6e40630ab6..94a9e58eae 100644
--- a/synapse/api/errors.py
+++ b/synapse/api/errors.py
@@ -21,17 +21,17 @@ import typing
 from http import HTTPStatus
 from typing import Dict, List, Optional, Union
 
-from canonicaljson import json
-
 from twisted.web import http
 
+from synapse.util import json_decoder
+
 if typing.TYPE_CHECKING:
     from synapse.types import JsonDict
 
 logger = logging.getLogger(__name__)
 
 
-class Codes(object):
+class Codes:
     UNRECOGNIZED = "M_UNRECOGNIZED"
     UNAUTHORIZED = "M_UNAUTHORIZED"
     FORBIDDEN = "M_FORBIDDEN"
@@ -593,7 +593,7 @@ class HttpResponseException(CodeMessageException):
         # try to parse the body as json, to get better errcode/msg, but
         # default to M_UNKNOWN with the HTTP status as the error text
         try:
-            j = json.loads(self.response.decode("utf-8"))
+            j = json_decoder.decode(self.response.decode("utf-8"))
         except ValueError:
             j = {}
 
@@ -604,3 +604,11 @@ class HttpResponseException(CodeMessageException):
         errmsg = j.pop("error", self.msg)
 
         return ProxiedRequestError(self.code, errmsg, errcode, j)
+
+
+class ShadowBanError(Exception):
+    """
+    Raised when a shadow-banned user attempts to perform an action.
+
+    This should be caught and a proper "fake" success response sent to the user.
+    """