1 files changed, 12 insertions, 0 deletions
diff --git a/synapse/types.py b/synapse/types.py
index cc7c182a78..00e6e1c369 100644
--- a/synapse/types.py
+++ b/synapse/types.py
@@ -229,6 +229,18 @@ def contains_invalid_mxid_characters(localpart):
     return any(c not in mxid_localpart_allowed_characters for c in localpart)
 
 
+def strip_invalid_mxid_characters(localpart):
+    """Removes any invalid characters from an mxid
+
+    Args:
+        localpart (basestring): the localpart to be stripped
+
+    Returns:
+        localpart (basestring): the localpart having been stripped
+    """
+    return filter(lambda c: c in mxid_localpart_allowed_characters, localpart)
+
+
 class StreamToken(
     namedtuple("Token", (
         "room_key",