From 52d12ca78232d54f5be516f82e2cebdd8b498516 Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Thu, 8 Dec 2016 13:32:05 +0000
Subject: [PATCH] Add /room/<room_id>/joined_members API

This returns the currently joined members in the room with their display
names and avatar urls. This is more efficient than /members for large
rooms where you don't need the full events.
---
 synapse/push/bulk_push_rule_evaluator.py | 12 ++++++------
 synapse/rest/client/v1/room.py           | 19 +++++++++++++++++++
 synapse/storage/roommember.py            | 16 +++++++++++++---
 3 files changed, 38 insertions(+), 9 deletions(-)

diff --git a/synapse/push/bulk_push_rule_evaluator.py b/synapse/push/bulk_push_rule_evaluator.py
index be55598c43..78b095c903 100644
--- a/synapse/push/bulk_push_rule_evaluator.py
+++ b/synapse/push/bulk_push_rule_evaluator.py
@@ -87,12 +87,12 @@ class BulkPushRuleEvaluator:
         condition_cache = {}
 
         for uid, rules in self.rules_by_user.items():
-            display_name = None
-            member_ev_id = context.current_state_ids.get((EventTypes.Member, uid))
-            if member_ev_id:
-                member_ev = yield self.store.get_event(member_ev_id, allow_none=True)
-                if member_ev:
-                    display_name = member_ev.content.get("displayname", None)
+            display_name = room_members.get(uid, {}).get("display_name", None)
+            if not display_name:
+                # Handle the case where we are pushing a membership event to
+                # that user, as they might not be already joined.
+                if event.type == EventTypes.Member and event.state_key == uid:
+                    display_name = event.content.get("displayname", None)
 
             filtered = filtered_by_user[uid]
             if len(filtered) == 0:
diff --git a/synapse/rest/client/v1/room.py b/synapse/rest/client/v1/room.py
index 3040f94867..a0bba1fa3b 100644
--- a/synapse/rest/client/v1/room.py
+++ b/synapse/rest/client/v1/room.py
@@ -369,6 +369,24 @@ class RoomMemberListRestServlet(ClientV1RestServlet):
         }))
 
 
+class JoinedRoomMemberListRestServlet(ClientV1RestServlet):
+    PATTERNS = client_path_patterns("/rooms/(?P<room_id>[^/]*)/joined_members$")
+
+    def __init__(self, hs):
+        super(JoinedRoomMemberListRestServlet, self).__init__(hs)
+        self.state = hs.get_state_handler()
+
+    @defer.inlineCallbacks
+    def on_GET(self, request, room_id):
+        yield self.auth.get_user_by_req(request)
+
+        users_with_profile = yield self.state.get_current_user_in_room(room_id)
+
+        defer.returnValue((200, {
+            "joined": users_with_profile
+        }))
+
+
 # TODO: Needs better unit testing
 class RoomMessageListRestServlet(ClientV1RestServlet):
     PATTERNS = client_path_patterns("/rooms/(?P<room_id>[^/]*)/messages$")
@@ -743,6 +761,7 @@ def register_servlets(hs, http_server):
     RoomStateEventRestServlet(hs).register(http_server)
     RoomCreateRestServlet(hs).register(http_server)
     RoomMemberListRestServlet(hs).register(http_server)
+    JoinedRoomMemberListRestServlet(hs).register(http_server)
     RoomMessageListRestServlet(hs).register(http_server)
     JoinRoomAliasServlet(hs).register(http_server)
     RoomForgetRestServlet(hs).register(http_server)
diff --git a/synapse/storage/roommember.py b/synapse/storage/roommember.py
index 7bf9040c0a..b2a45a38c1 100644
--- a/synapse/storage/roommember.py
+++ b/synapse/storage/roommember.py
@@ -409,7 +409,7 @@ class RoomMemberStore(SQLBaseStore):
             table="room_memberships",
             column="event_id",
             iterable=member_event_ids,
-            retcols=['user_id'],
+            retcols=['user_id', 'display_name', 'avatar_url'],
             keyvalues={
                 "membership": Membership.JOIN,
             },
@@ -417,11 +417,21 @@ class RoomMemberStore(SQLBaseStore):
             desc="_get_joined_users_from_context",
         )
 
-        users_in_room = set(row["user_id"] for row in rows)
+        users_in_room = {
+            row["user_id"]: {
+                "display_name": row["display_name"],
+                "avatar_url": row["avatar_url"],
+            }
+            for row in rows
+        }
+
         if event is not None and event.type == EventTypes.Member:
             if event.membership == Membership.JOIN:
                 if event.event_id in member_event_ids:
-                    users_in_room.add(event.state_key)
+                    users_in_room[event.state_key] = {
+                        "display_name": event.content.get("displayname", None),
+                        "avatar_url": event.content.get("avatar_url", None),
+                    }
 
         defer.returnValue(users_in_room)