1 files changed, 27 insertions, 0 deletions
diff --git a/synapse/federation/federation_base.py b/synapse/federation/federation_base.py
index a0f5d40eb3..7918d3e442 100644
--- a/synapse/federation/federation_base.py
+++ b/synapse/federation/federation_base.py
@@ -16,7 +16,9 @@ import logging
 
 from synapse.api.errors import SynapseError
 from synapse.crypto.event_signing import check_event_content_hash
+from synapse.events import FrozenEvent
 from synapse.events.utils import prune_event
+from synapse.http.servlet import assert_params_in_request
 from synapse.util import unwrapFirstError, logcontext
 from twisted.internet import defer
 
@@ -169,3 +171,28 @@ class FederationBase(object):
             )
 
         return deferreds
+
+
+def event_from_pdu_json(pdu_json, outlier=False):
+    """Construct a FrozenEvent from an event json received over federation
+
+    Args:
+        pdu_json (object): pdu as received over federation
+        outlier (bool): True to mark this event as an outlier
+
+    Returns:
+        FrozenEvent
+
+    Raises:
+        SynapseError: if the pdu is missing required fields
+    """
+    # we could probably enforce a bunch of other fields here (room_id, sender,
+    # origin, etc etc)
+    assert_params_in_request(pdu_json, ('event_id', 'type'))
+    event = FrozenEvent(
+        pdu_json
+    )
+
+    event.internal_metadata.outlier = outlier
+
+    return event