1 files changed, 48 insertions, 0 deletions
diff --git a/synapse/util/threepids.py b/synapse/util/threepids.py
new file mode 100644
index 0000000000..75efa0117b
--- /dev/null
+++ b/synapse/util/threepids.py
@@ -0,0 +1,48 @@
+# -*- coding: utf-8 -*-
+# Copyright 2018 New Vector Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import logging
+import re
+
+logger = logging.getLogger(__name__)
+
+
+def check_3pid_allowed(hs, medium, address):
+    """Checks whether a given format of 3PID is allowed to be used on this HS
+
+    Args:
+        hs (synapse.server.HomeServer): server
+        medium (str): 3pid medium - e.g. email, msisdn
+        address (str): address within that medium (e.g. "wotan@matrix.org")
+            msisdns need to first have been canonicalised
+    Returns:
+        bool: whether the 3PID medium/address is allowed to be added to this HS
+    """
+
+    if hs.config.allowed_local_3pids:
+        for constraint in hs.config.allowed_local_3pids:
+            logger.debug(
+                "Checking 3PID %s (%s) against %s (%s)",
+                address, medium, constraint['pattern'], constraint['medium'],
+            )
+            if (
+                medium == constraint['medium'] and
+                re.match(constraint['pattern'], address)
+            ):
+                return True
+    else:
+        return True
+
+    return False