make /context lazyload & filter aware (#3567)

make /context lazyload & filter aware.

changelog.d/3567.feature

+make the /context API filter & lazy-load aware as per MSC1227

synapse/handlers/room.py

@@ -15,6 +15,7 @@
 # limitations under the License.
 
 """Contains functions for performing events on rooms."""
+import itertools
 import logging
 import math
 import string
@@ -401,7 +402,7 @@ class RoomContextHandler(object):
         self.store = hs.get_datastore()
 
     @defer.inlineCallbacks
-    def get_event_context(self, user, room_id, event_id, limit):
+    def get_event_context(self, user, room_id, event_id, limit, event_filter):
         """Retrieves events, pagination tokens and state around a given event
         in a room.
 
@@ -411,6 +412,8 @@ class RoomContextHandler(object):
             event_id (str)
             limit (int): The maximum number of events to return in total
                 (excluding state).
+            event_filter (Filter|None): the filter to apply to the events returned
+                (excluding the target event_id)
 
         Returns:
             dict, or None if the event isn't found
@@ -443,7 +446,7 @@ class RoomContextHandler(object):
             )
 
         results = yield self.store.get_events_around(
-            room_id, event_id, before_limit, after_limit
+            room_id, event_id, before_limit, after_limit, event_filter
         )
 
         results["events_before"] = yield filter_evts(results["events_before"])
@@ -455,8 +458,23 @@ class RoomContextHandler(object):
         else:
             last_event_id = event_id
 
+        types = None
+        filtered_types = None
+        if event_filter and event_filter.lazy_load_members():
+            members = set(ev.sender for ev in itertools.chain(
+                results["events_before"],
+                (results["event"],),
+                results["events_after"],
+            ))
+            filtered_types = [EventTypes.Member]
+            types = [(EventTypes.Member, member) for member in members]
+
+        # XXX: why do we return the state as of the last event rather than the
+        # first? Shouldn't we be consistent with /sync?
+        # https://github.com/matrix-org/matrix-doc/issues/687
+
         state = yield self.store.get_state_for_events(
-            [last_event_id], None
+            [last_event_id], types, filtered_types=filtered_types,
         )
         results["state"] = list(state[last_event_id].values())
 

synapse/handlers/search.py

@@ -287,7 +287,7 @@ class SearchHandler(BaseHandler):
             contexts = {}
             for event in allowed_events:
                 res = yield self.store.get_events_around(
-                    event.room_id, event.event_id, before_limit, after_limit
+                    event.room_id, event.event_id, before_limit, after_limit,
                 )
 
                 logger.info(

synapse/rest/client/v1/room.py

@@ -531,11 +531,20 @@ class RoomEventContextServlet(ClientV1RestServlet):
 
         limit = parse_integer(request, "limit", default=10)
 
+        # picking the API shape for symmetry with /messages
+        filter_bytes = parse_string(request, "filter")
+        if filter_bytes:
+            filter_json = urlparse.unquote(filter_bytes).decode("UTF-8")
+            event_filter = Filter(json.loads(filter_json))
+        else:
+            event_filter = None
+
         results = yield self.room_context_handler.get_event_context(
             requester.user,
             room_id,
             event_id,
             limit,
+            event_filter,
         )
 
         if not results:

synapse/storage/stream.py

@@ -527,7 +527,9 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
             )
 
     @defer.inlineCallbacks
-    def get_events_around(self, room_id, event_id, before_limit, after_limit):
+    def get_events_around(
+        self, room_id, event_id, before_limit, after_limit, event_filter=None,
+    ):
         """Retrieve events and pagination tokens around a given event in a
         room.
 
@@ -536,6 +538,7 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
             event_id (str)
             before_limit (int)
             after_limit (int)
+            event_filter (Filter|None)
 
         Returns:
             dict
@@ -543,7 +546,7 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
 
         results = yield self.runInteraction(
             "get_events_around", self._get_events_around_txn,
-            room_id, event_id, before_limit, after_limit
+            room_id, event_id, before_limit, after_limit, event_filter,
         )
 
         events_before = yield self._get_events(
@@ -563,7 +566,9 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
             "end": results["after"]["token"],
         })
 
-    def _get_events_around_txn(self, txn, room_id, event_id, before_limit, after_limit):
+    def _get_events_around_txn(
+        self, txn, room_id, event_id, before_limit, after_limit, event_filter,
+    ):
         """Retrieves event_ids and pagination tokens around a given event in a
         room.
 
@@ -572,6 +577,7 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
             event_id (str)
             before_limit (int)
             after_limit (int)
+            event_filter (Filter|None)
 
         Returns:
             dict
@@ -601,11 +607,13 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
 
         rows, start_token = self._paginate_room_events_txn(
             txn, room_id, before_token, direction='b', limit=before_limit,
+            event_filter=event_filter,
         )
         events_before = [r.event_id for r in rows]
 
         rows, end_token = self._paginate_room_events_txn(
             txn, room_id, after_token, direction='f', limit=after_limit,
+            event_filter=event_filter,
         )
         events_after = [r.event_id for r in rows]