Add filter_event_fields and filter_field to FilterCollection

This commit is contained in:
Kegan Dougal 2016-11-21 15:18:18 +00:00
parent dc6cede78e
commit e90fcd9edd

View File

@ -18,6 +18,7 @@ from synapse.types import UserID, RoomID
from twisted.internet import defer from twisted.internet import defer
import ujson as json import ujson as json
import re
class Filtering(object): class Filtering(object):
@ -71,6 +72,21 @@ class Filtering(object):
if key in user_filter_json["room"]: if key in user_filter_json["room"]:
self._check_definition(user_filter_json["room"][key]) self._check_definition(user_filter_json["room"][key])
if "event_fields" in user_filter_json:
if type(user_filter_json["event_fields"]) != list:
raise SynapseError(400, "event_fields must be a list of strings")
for field in user_filter_json["event_fields"]:
if not isinstance(field, basestring):
raise SynapseError(400, "Event field must be a string")
# Don't allow '\\' in event field filters. This makes matching
# events a lot easier as we can then use a negative lookbehind
# assertion to split '\.' If we allowed \\ then it would
# incorrectly split '\\.'
if r'\\' in field:
raise SynapseError(
400, r'The escape character \ cannot itself be escaped'
)
def _check_definition_room_lists(self, definition): def _check_definition_room_lists(self, definition):
"""Check that "rooms" and "not_rooms" are lists of room ids if they """Check that "rooms" and "not_rooms" are lists of room ids if they
are present are present
@ -152,6 +168,11 @@ class FilterCollection(object):
self.include_leave = filter_json.get("room", {}).get( self.include_leave = filter_json.get("room", {}).get(
"include_leave", False "include_leave", False
) )
self._event_fields = filter_json.get("event_fields", [])
# Negative lookbehind assertion for '\'
# (?<!stuff) matches if the current position in the string is not preceded
# by a match for 'stuff'.
self._split_field_regex = re.compile(r'(?<!\\)\.')
def __repr__(self): def __repr__(self):
return "<FilterCollection %s>" % (json.dumps(self._filter_json),) return "<FilterCollection %s>" % (json.dumps(self._filter_json),)
@ -186,6 +207,54 @@ class FilterCollection(object):
def filter_room_account_data(self, events): def filter_room_account_data(self, events):
return self._room_account_data.filter(self._room_filter.filter(events)) return self._room_account_data.filter(self._room_filter.filter(events))
def filter_event_fields(self, event):
"""Remove fields from an event in accordance with the 'event_fields' of a filter.
If there are no event fields specified then all fields are included.
The entries may include '.' charaters to indicate sub-fields.
So ['content.body'] will include the 'body' field of the 'content' object.
A literal '.' character in a field name may be escaped using a '\'.
Args:
event(dict): The raw event to filter
Returns:
dict: The same event with some fields missing, if required.
"""
for field in self._event_fields:
self.filter_field(event, field)
return event
def filter_field(self, dictionary, field):
"""Filter the given field from the given dictionary.
Args:
dictionary(dict): The dictionary to remove the field from.
field(str): The key to remove.
Returns:
dict: The same dictionary with the field removed.
"""
# "content.body.thing\.with\.dots" => ["content", "body", "thing\.with\.dots"]
sub_fields = self._split_field_regex.split(field)
# remove escaping so we can use the right key names when deleting
sub_fields = [f.replace(r'\.', r'.') for f in sub_fields]
# common case e.g. 'origin_server_ts'
if len(sub_fields) == 1:
dictionary.pop(sub_fields[0], None)
# nested field e.g. 'content.body'
elif len(sub_fields) > 1:
# Pop the last field as that's the key to delete and we need the
# parent dict in order to remove the key. Drill down to the right dict.
key_to_delete = sub_fields.pop(-1)
sub_dict = dictionary
for sub_field in sub_fields:
if sub_field in sub_dict and type(sub_dict[sub_field]) == dict:
sub_dict = sub_dict[sub_field]
else:
return dictionary
sub_dict.pop(key_to_delete, None)
return dictionary
class Filter(object): class Filter(object):
def __init__(self, filter_json): def __init__(self, filter_json):