Sliding Sync: Add Account Data extension (MSC3959) (#17477)

Extensions based on
[MSC3575](https://github.com/matrix-org/matrix-spec-proposals/pull/3575):
Sliding Sync

1 files changed, 18 insertions, 1 deletions

diff --git a/synapse/rest/client/sync.py b/synapse/rest/client/sync.py

index d72dfa2b10..7cf1f56435 100644
--- a/synapse/rest/client/sync.py
+++ b/synapse/rest/client/sync.py
@@ -929,7 +929,6 @@ class SlidingSyncRestServlet(RestServlet):
 
         return 200, response_content
 
-    # TODO: Is there a better way to encode things?
     async def encode_response(
         self,
         requester: Requester,
@@ -1117,6 +1116,24 @@ class SlidingSyncRestServlet(RestServlet):
                     extensions.e2ee.device_list_updates.left
                 )
 
+        if extensions.account_data is not None:
+            serialized_extensions["account_data"] = {
+                # Same as the the top-level `account_data.events` field in Sync v2.
+                "global": [
+                    {"type": account_data_type, "content": content}
+                    for account_data_type, content in extensions.account_data.global_account_data_map.items()
+                ],
+                # Same as the joined room's account_data field in Sync v2, e.g the path
+                # `rooms.join["!foo:bar"].account_data.events`.
+                "rooms": {
+                    room_id: [
+                        {"type": account_data_type, "content": content}
+                        for account_data_type, content in event_map.items()
+                    ]
+                    for room_id, event_map in extensions.account_data.account_data_by_room_map.items()
+                },
+            }
+
         return serialized_extensions