diff options
Diffstat (limited to 'synapse/handlers/space_summary.py')
| -rw-r--r-- | synapse/handlers/space_summary.py | 201 |
1 files changed, 198 insertions, 3 deletions
diff --git a/synapse/handlers/space_summary.py b/synapse/handlers/space_summary.py index d04afe6c31..fd76c34695 100644 --- a/synapse/handlers/space_summary.py +++ b/synapse/handlers/space_summary.py @@ -18,7 +18,7 @@ import re from collections import deque from typing import ( TYPE_CHECKING, - Collection, + Deque, Dict, Iterable, List, @@ -38,9 +38,12 @@ from synapse.api.constants import ( Membership, RoomTypes, ) +from synapse.api.errors import Codes, SynapseError from synapse.events import EventBase from synapse.events.utils import format_event_for_client_v2 from synapse.types import JsonDict +from synapse.util.caches.response_cache import ResponseCache +from synapse.util.stringutils import random_string if TYPE_CHECKING: from synapse.server import HomeServer @@ -57,6 +60,29 @@ MAX_ROOMS_PER_SPACE = 50 MAX_SERVERS_PER_SPACE = 3 +@attr.s(slots=True, frozen=True, auto_attribs=True) +class _PaginationKey: + """The key used to find unique pagination session.""" + + # The first three entries match the request parameters (and cannot change + # during a pagination session). + room_id: str + suggested_only: bool + max_depth: Optional[int] + # The randomly generated token. + token: str + + +@attr.s(slots=True, frozen=True, auto_attribs=True) +class _PaginationSession: + """The information that is stored for pagination.""" + + # The queue of rooms which are still to process. + room_queue: Deque["_RoomQueueEntry"] + # A set of rooms which have been processed. + processed_rooms: Set[str] + + class SpaceSummaryHandler: def __init__(self, hs: "HomeServer"): self._clock = hs.get_clock() @@ -67,6 +93,21 @@ class SpaceSummaryHandler: self._server_name = hs.hostname self._federation_client = hs.get_federation_client() + # A map of query information to the current pagination state. + # + # TODO Allow for multiple workers to share this data. + # TODO Expire pagination tokens. + self._pagination_sessions: Dict[_PaginationKey, _PaginationSession] = {} + + # If a user tries to fetch the same page multiple times in quick succession, + # only process the first attempt and return its result to subsequent requests. + self._pagination_response_cache: ResponseCache[ + Tuple[str, bool, Optional[int], Optional[int], Optional[str]] + ] = ResponseCache( + hs.get_clock(), + "get_room_hierarchy", + ) + async def get_space_summary( self, requester: str, @@ -130,7 +171,7 @@ class SpaceSummaryHandler: requester, None, room_id, suggested_only, max_children ) - events: Collection[JsonDict] = [] + events: Sequence[JsonDict] = [] if room_entry: rooms_result.append(room_entry.room) events = room_entry.children @@ -207,6 +248,154 @@ class SpaceSummaryHandler: return {"rooms": rooms_result, "events": events_result} + async def get_room_hierarchy( + self, + requester: str, + requested_room_id: str, + suggested_only: bool = False, + max_depth: Optional[int] = None, + limit: Optional[int] = None, + from_token: Optional[str] = None, + ) -> JsonDict: + """ + Implementation of the room hierarchy C-S API. + + Args: + requester: The user ID of the user making this request. + requested_room_id: The room ID to start the hierarchy at (the "root" room). + suggested_only: Whether we should only return children with the "suggested" + flag set. + max_depth: The maximum depth in the tree to explore, must be a + non-negative integer. + + 0 would correspond to just the root room, 1 would include just + the root room's children, etc. + limit: An optional limit on the number of rooms to return per + page. Must be a positive integer. + from_token: An optional pagination token. + + Returns: + The JSON hierarchy dictionary. + """ + # If a user tries to fetch the same page multiple times in quick succession, + # only process the first attempt and return its result to subsequent requests. + # + # This is due to the pagination process mutating internal state, attempting + # to process multiple requests for the same page will result in errors. + return await self._pagination_response_cache.wrap( + (requested_room_id, suggested_only, max_depth, limit, from_token), + self._get_room_hierarchy, + requester, + requested_room_id, + suggested_only, + max_depth, + limit, + from_token, + ) + + async def _get_room_hierarchy( + self, + requester: str, + requested_room_id: str, + suggested_only: bool = False, + max_depth: Optional[int] = None, + limit: Optional[int] = None, + from_token: Optional[str] = None, + ) -> JsonDict: + """See docstring for SpaceSummaryHandler.get_room_hierarchy.""" + + # first of all, check that the user is in the room in question (or it's + # world-readable) + await self._auth.check_user_in_room_or_world_readable( + requested_room_id, requester + ) + + # If this is continuing a previous session, pull the persisted data. + if from_token: + pagination_key = _PaginationKey( + requested_room_id, suggested_only, max_depth, from_token + ) + if pagination_key not in self._pagination_sessions: + raise SynapseError(400, "Unknown pagination token", Codes.INVALID_PARAM) + + # Load the previous state. + pagination_session = self._pagination_sessions[pagination_key] + room_queue = pagination_session.room_queue + processed_rooms = pagination_session.processed_rooms + else: + # the queue of rooms to process + room_queue = deque((_RoomQueueEntry(requested_room_id, ()),)) + + # Rooms we have already processed. + processed_rooms = set() + + rooms_result: List[JsonDict] = [] + + # Cap the limit to a server-side maximum. + if limit is None: + limit = MAX_ROOMS + else: + limit = min(limit, MAX_ROOMS) + + # Iterate through the queue until we reach the limit or run out of + # rooms to include. + while room_queue and len(rooms_result) < limit: + queue_entry = room_queue.popleft() + room_id = queue_entry.room_id + current_depth = queue_entry.depth + if room_id in processed_rooms: + # already done this room + continue + + logger.debug("Processing room %s", room_id) + + is_in_room = await self._store.is_host_joined(room_id, self._server_name) + if is_in_room: + room_entry = await self._summarize_local_room( + requester, + None, + room_id, + suggested_only, + # TODO Handle max children. + max_children=None, + ) + + if room_entry: + rooms_result.append(room_entry.as_json()) + + # Add the child to the queue. We have already validated + # that the vias are a list of server names. + # + # If the current depth is the maximum depth, do not queue + # more entries. + if max_depth is None or current_depth < max_depth: + room_queue.extendleft( + _RoomQueueEntry( + ev["state_key"], ev["content"]["via"], current_depth + 1 + ) + for ev in reversed(room_entry.children) + ) + + processed_rooms.add(room_id) + else: + # TODO Federation. + pass + + result: JsonDict = {"rooms": rooms_result} + + # If there's additional data, generate a pagination token (and persist state). + if room_queue: + next_token = random_string(24) + result["next_token"] = next_token + pagination_key = _PaginationKey( + requested_room_id, suggested_only, max_depth, next_token + ) + self._pagination_sessions[pagination_key] = _PaginationSession( + room_queue, processed_rooms + ) + + return result + async def federation_space_summary( self, origin: str, @@ -652,6 +841,7 @@ class SpaceSummaryHandler: class _RoomQueueEntry: room_id: str via: Sequence[str] + depth: int = 0 @attr.s(frozen=True, slots=True, auto_attribs=True) @@ -662,7 +852,12 @@ class _RoomEntry: # An iterable of the sorted, stripped children events for children of this room. # # This may not include all children. - children: Collection[JsonDict] = () + children: Sequence[JsonDict] = () + + def as_json(self) -> JsonDict: + result = dict(self.room) + result["children_state"] = self.children + return result def _has_valid_via(e: EventBase) -> bool: |