Configurable maximum number of events requested by /sync and /messages

synapse/config/server.py

@@ -35,6 +35,8 @@ def read_config(self, config):
         # "disable" federation
         self.send_federation = config.get("send_federation", True)
 
+        self.filter_timeline_limit = config.get("filter_timeline_limit", -1)
+
         if self.public_baseurl is not None:
             if self.public_baseurl[-1] != '/':
                 self.public_baseurl += '/'
@@ -161,6 +163,10 @@ def default_config(self, server_name, **kwargs):
         # The GC threshold parameters to pass to `gc.set_threshold`, if defined
         # gc_thresholds: [700, 10, 10]
 
+        # 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.
+        # filter_timeline_limit: 5000
+
         # List of ports that Synapse should listen on, their purpose and their
         # configuration.
         listeners:

synapse/rest/client/v2_alpha/_base.py

@@ -47,3 +47,13 @@ def client_v2_patterns(path_regex, releases=(0,),
         new_prefix = CLIENT_V2_ALPHA_PREFIX.replace("/v2_alpha", "/r%d" % release)
         patterns.append(re.compile("^" + new_prefix + path_regex))
     return patterns
+
+
+def set_timeline_upper_limit(filter_json, filter_timeline_limit):
+    if filter_timeline_limit < 0:
+        return  # no upper limits
+    timeline = filter_json.get('room', {}).get('timeline', {})
+    if 'limit' in timeline:
+        filter_json['room']['timeline']["limit"] = min(
+            filter_json['room']['timeline']['limit'],
+            filter_timeline_limit)

synapse/rest/client/v2_alpha/filter.py

@@ -20,6 +20,7 @@
 from synapse.types import UserID
 
 from ._base import client_v2_patterns
+from ._base import set_timeline_upper_limit
 
 import logging
 
@@ -85,6 +86,11 @@ def on_POST(self, request, user_id):
             raise AuthError(403, "Can only create filters for local users")
 
         content = parse_json_object_from_request(request)
+        set_timeline_upper_limit(
+            content,
+            self.hs.config.filter_timeline_limit
+        )
+
         filter_id = yield self.filtering.add_user_filter(
             user_localpart=target_user.localpart,
             user_filter=content,

synapse/rest/client/v2_alpha/sync.py

@@ -28,6 +28,7 @@
 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
@@ -78,6 +79,7 @@ class SyncRestServlet(RestServlet):
 
     def __init__(self, hs):
         super(SyncRestServlet, self).__init__()
+        self.hs = hs
         self.auth = hs.get_auth()
         self.sync_handler = hs.get_sync_handler()
         self.clock = hs.get_clock()
@@ -121,6 +123,8 @@ def on_GET(self, request):
             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)