Merge pull request #37 from matrix-org/client_v2_filter

Client v2 filter

1 files changed, 229 insertions, 0 deletions

diff --git a/synapse/api/filtering.py b/synapse/api/filtering.py
new file mode 100644
index 0000000000..4d570b74f8
--- /dev/null
+++ b/synapse/api/filtering.py
@@ -0,0 +1,229 @@
+# -*- coding: utf-8 -*-
+# Copyright 2015 OpenMarket Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+from synapse.api.errors import SynapseError
+from synapse.types import UserID, RoomID
+
+
+class Filtering(object):
+
+    def __init__(self, hs):
+        super(Filtering, self).__init__()
+        self.store = hs.get_datastore()
+
+    def get_user_filter(self, user_localpart, filter_id):
+        result = self.store.get_user_filter(user_localpart, filter_id)
+        result.addCallback(Filter)
+        return result
+
+    def add_user_filter(self, user_localpart, user_filter):
+        self._check_valid_filter(user_filter)
+        return self.store.add_user_filter(user_localpart, user_filter)
+
+    # TODO(paul): surely we should probably add a delete_user_filter or
+    #   replace_user_filter at some point? There's no REST API specified for
+    #   them however
+
+    def _check_valid_filter(self, user_filter_json):
+        """Check if the provided filter is valid.
+
+        This inspects all definitions contained within the filter.
+
+        Args:
+            user_filter_json(dict): The filter
+        Raises:
+            SynapseError: If the filter is not valid.
+        """
+        # NB: Filters are the complete json blobs. "Definitions" are an
+        # individual top-level key e.g. public_user_data. Filters are made of
+        # many definitions.
+
+        top_level_definitions = [
+            "public_user_data", "private_user_data", "server_data"
+        ]
+
+        room_level_definitions = [
+            "state", "events", "ephemeral"
+        ]
+
+        for key in top_level_definitions:
+            if key in user_filter_json:
+                self._check_definition(user_filter_json[key])
+
+        if "room" in user_filter_json:
+            for key in room_level_definitions:
+                if key in user_filter_json["room"]:
+                    self._check_definition(user_filter_json["room"][key])
+
+    def _check_definition(self, definition):
+        """Check if the provided definition is valid.
+
+        This inspects not only the types but also the values to make sure they
+        make sense.
+
+        Args:
+            definition(dict): The filter definition
+        Raises:
+            SynapseError: If there was a problem with this definition.
+        """
+        # NB: Filters are the complete json blobs. "Definitions" are an
+        # individual top-level key e.g. public_user_data. Filters are made of
+        # many definitions.
+        if type(definition) != dict:
+            raise SynapseError(
+                400, "Expected JSON object, not %s" % (definition,)
+            )
+
+        # check rooms are valid room IDs
+        room_id_keys = ["rooms", "not_rooms"]
+        for key in room_id_keys:
+            if key in definition:
+                if type(definition[key]) != list:
+                    raise SynapseError(400, "Expected %s to be a list." % key)
+                for room_id in definition[key]:
+                    RoomID.from_string(room_id)
+
+        # check senders are valid user IDs
+        user_id_keys = ["senders", "not_senders"]
+        for key in user_id_keys:
+            if key in definition:
+                if type(definition[key]) != list:
+                    raise SynapseError(400, "Expected %s to be a list." % key)
+                for user_id in definition[key]:
+                    UserID.from_string(user_id)
+
+        # TODO: We don't limit event type values but we probably should...
+        # check types are valid event types
+        event_keys = ["types", "not_types"]
+        for key in event_keys:
+            if key in definition:
+                if type(definition[key]) != list:
+                    raise SynapseError(400, "Expected %s to be a list." % key)
+                for event_type in definition[key]:
+                    if not isinstance(event_type, basestring):
+                        raise SynapseError(400, "Event type should be a string")
+
+        if "format" in definition:
+            event_format = definition["format"]
+            if event_format not in ["federation", "events"]:
+                raise SynapseError(400, "Invalid format: %s" % (event_format,))
+
+        if "select" in definition:
+            event_select_list = definition["select"]
+            for select_key in event_select_list:
+                if select_key not in ["event_id", "origin_server_ts",
+                                      "thread_id", "content", "content.body"]:
+                    raise SynapseError(400, "Bad select: %s" % (select_key,))
+
+        if ("bundle_updates" in definition and
+                type(definition["bundle_updates"]) != bool):
+            raise SynapseError(400, "Bad bundle_updates: expected bool.")
+
+
+class Filter(object):
+    def __init__(self, filter_json):
+        self.filter_json = filter_json
+
+    def filter_public_user_data(self, events):
+        return self._filter_on_key(events, ["public_user_data"])
+
+    def filter_private_user_data(self, events):
+        return self._filter_on_key(events, ["private_user_data"])
+
+    def filter_room_state(self, events):
+        return self._filter_on_key(events, ["room", "state"])
+
+    def filter_room_events(self, events):
+        return self._filter_on_key(events, ["room", "events"])
+
+    def filter_room_ephemeral(self, events):
+        return self._filter_on_key(events, ["room", "ephemeral"])
+
+    def _filter_on_key(self, events, keys):
+        filter_json = self.filter_json
+        if not filter_json:
+            return events
+
+        try:
+            # extract the right definition from the filter
+            definition = filter_json
+            for key in keys:
+                definition = definition[key]
+            return self._filter_with_definition(events, definition)
+        except KeyError:
+            # return all events if definition isn't specified.
+            return events
+
+    def _filter_with_definition(self, events, definition):
+        return [e for e in events if self._passes_definition(definition, e)]
+
+    def _passes_definition(self, definition, event):
+        """Check if the event passes through the given definition.
+
+        Args:
+            definition(dict): The definition to check against.
+            event(Event): The event to check.
+        Returns:
+            True if the event passes through the filter.
+        """
+        # Algorithm notes:
+        # For each key in the definition, check the event meets the criteria:
+        #   * For types: Literal match or prefix match (if ends with wildcard)
+        #   * For senders/rooms: Literal match only
+        #   * "not_" checks take presedence (e.g. if "m.*" is in both 'types'
+        #     and 'not_types' then it is treated as only being in 'not_types')
+
+        # room checks
+        if hasattr(event, "room_id"):
+            room_id = event.room_id
+            allow_rooms = definition.get("rooms", None)
+            reject_rooms = definition.get("not_rooms", None)
+            if reject_rooms and room_id in reject_rooms:
+                return False
+            if allow_rooms and room_id not in allow_rooms:
+                return False
+
+        # sender checks
+        if hasattr(event, "sender"):
+            # Should we be including event.state_key for some event types?
+            sender = event.sender
+            allow_senders = definition.get("senders", None)
+            reject_senders = definition.get("not_senders", None)
+            if reject_senders and sender in reject_senders:
+                return False
+            if allow_senders and sender not in allow_senders:
+                return False
+
+        # type checks
+        if "not_types" in definition:
+            for def_type in definition["not_types"]:
+                if self._event_matches_type(event, def_type):
+                    return False
+        if "types" in definition:
+            included = False
+            for def_type in definition["types"]:
+                if self._event_matches_type(event, def_type):
+                    included = True
+                    break
+            if not included:
+                return False
+
+        return True
+
+    def _event_matches_type(self, event, def_type):
+        if def_type.endswith("*"):
+            type_prefix = def_type[:-1]
+            return event.type.startswith(type_prefix)
+        else:
+            return event.type == def_type