Configurable maximum number of events requested by /sync and /messages (#2220)

Set the limit on the returned events in the timeline in the get and sync
operations. The default value is -1, means no upper limit.

For example, using `filter_timeline_limit: 5000`:

POST /_matrix/client/r0/user/user:id/filter
{
room: {
    timeline: {
      limit: 1000000000000000000
    }
}
}

GET /_matrix/client/r0/user/user:id/filter/filter:id

{
room: {
    timeline: {
      limit: 5000
    }
}
}

The server cuts down the room.timeline.limit.

1 files changed, 3 insertions, 0 deletions

diff --git a/synapse/rest/client/v2_alpha/sync.py b/synapse/rest/client/v2_alpha/sync.py
index f30eab76fd..f5e7349c5c 100644
--- a/synapse/rest/client/v2_alpha/sync.py
+++ b/synapse/rest/client/v2_alpha/sync.py
@@ -28,6 +28,7 @@ from synapse.api.filtering import FilterCollection, DEFAULT_FILTER_COLLECTION
 from synapse.api.errors import SynapseError
 from synapse.api.constants import PresenceState
 from ._base import client_v2_patterns
+from ._base import set_timeline_upper_limit
 
 import itertools
 import logging
@@ -121,6 +122,8 @@ class SyncRestServlet(RestServlet):
             if filter_id.startswith('{'):
                 try:
                     filter_object = json.loads(filter_id)
+                    set_timeline_upper_limit(filter_object,
+                                             self.hs.config.filter_timeline_limit)
                 except:
                     raise SynapseError(400, "Invalid filter JSON")
                 self.filtering.check_valid_filter(filter_object)