anonymousland-synapse/synapse/federation/transport/client.py

# Copyright 2014-2021 The Matrix.org Foundation C.I.C.
# Copyright 2020 Sorunome
#
# 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.

import logging
import urllib
from typing import Any, Callable, Dict, Iterable, List, Mapping, Optional, Tuple, Union

import attr
import ijson

from synapse.api.constants import Membership
from synapse.api.errors import Codes, HttpResponseException, SynapseError
from synapse.api.room_versions import RoomVersion
from synapse.api.urls import (
    FEDERATION_UNSTABLE_PREFIX,
    FEDERATION_V1_PREFIX,
    FEDERATION_V2_PREFIX,
)
from synapse.events import EventBase, make_event_from_dict
from synapse.federation.units import Transaction
from synapse.http.matrixfederationclient import ByteParser
from synapse.logging.utils import log_function
from synapse.types import JsonDict

logger = logging.getLogger(__name__)

# Send join responses can be huge, so we set a separate limit here. The response
# is parsed in a streaming manner, which helps alleviate the issue of memory
# usage a bit.
MAX_RESPONSE_SIZE_SEND_JOIN = 500 * 1024 * 1024


class TransportLayerClient:
    """Sends federation HTTP requests to other servers"""

    def __init__(self, hs):
        self.server_name = hs.hostname
        self.client = hs.get_federation_http_client()

    @log_function
    async def get_room_state_ids(
        self, destination: str, room_id: str, event_id: str
    ) -> JsonDict:
        """Requests all state for a given room from the given server at the
        given event. Returns the state's event_id's

        Args:
            destination: The host name of the remote homeserver we want
                to get the state from.
            context: The name of the context we want the state of
            event_id: The event we want the context at.

        Returns:
            Results in a dict received from the remote homeserver.
        """
        logger.debug("get_room_state_ids dest=%s, room=%s", destination, room_id)

        path = _create_v1_path("/state_ids/%s", room_id)
        return await self.client.get_json(
            destination,
            path=path,
            args={"event_id": event_id},
            try_trailing_slash_on_400=True,
        )

    @log_function
    async def get_event(
        self, destination: str, event_id: str, timeout: Optional[int] = None
    ) -> JsonDict:
        """Requests the pdu with give id and origin from the given server.

        Args:
            destination: The host name of the remote homeserver we want
                to get the state from.
            event_id: The id of the event being requested.
            timeout: How long to try (in ms) the destination for before
                giving up. None indicates no timeout.

        Returns:
            Results in a dict received from the remote homeserver.
        """
        logger.debug("get_pdu dest=%s, event_id=%s", destination, event_id)

        path = _create_v1_path("/event/%s", event_id)
        return await self.client.get_json(
            destination, path=path, timeout=timeout, try_trailing_slash_on_400=True
        )

    @log_function
    async def backfill(
        self, destination: str, room_id: str, event_tuples: Iterable[str], limit: int
    ) -> Optional[JsonDict]:
        """Requests `limit` previous PDUs in a given context before list of
        PDUs.

        Args:
            destination
            room_id
            event_tuples
            limit

        Returns:
            Results in a dict received from the remote homeserver.
        """
        logger.debug(
            "backfill dest=%s, room_id=%s, event_tuples=%r, limit=%s",
            destination,
            room_id,
            event_tuples,
            str(limit),
        )

        if not event_tuples:
            # TODO: raise?
            return None

        path = _create_v1_path("/backfill/%s", room_id)

        args = {"v": event_tuples, "limit": [str(limit)]}

        return await self.client.get_json(
            destination, path=path, args=args, try_trailing_slash_on_400=True
        )

    @log_function
    async def send_transaction(
        self,
        transaction: Transaction,
        json_data_callback: Optional[Callable[[], JsonDict]] = None,
    ) -> JsonDict:
        """Sends the given Transaction to its destination

        Args:
            transaction (Transaction)

        Returns:
            Succeeds when we get a 2xx HTTP response. The result
            will be the decoded JSON body.

            Fails with ``HTTPRequestException`` if we get an HTTP response
            code >= 300.

            Fails with ``NotRetryingDestination`` if we are not yet ready
            to retry this server.

            Fails with ``FederationDeniedError`` if this destination
            is not on our federation whitelist
        """
        logger.debug(
            "send_data dest=%s, txid=%s",
            transaction.destination,  # type: ignore
            transaction.transaction_id,  # type: ignore
        )

        if transaction.destination == self.server_name:  # type: ignore
            raise RuntimeError("Transport layer cannot send to itself!")

        # FIXME: This is only used by the tests. The actual json sent is
        # generated by the json_data_callback.
        json_data = transaction.get_dict()

        path = _create_v1_path("/send/%s", transaction.transaction_id)  # type: ignore

        return await self.client.put_json(
            transaction.destination,  # type: ignore
            path=path,
            data=json_data,
            json_data_callback=json_data_callback,
            long_retries=True,
            backoff_on_404=True,  # If we get a 404 the other side has gone
            try_trailing_slash_on_400=True,
        )

    @log_function
    async def make_query(
        self, destination, query_type, args, retry_on_dns_fail, ignore_backoff=False
    ):
        path = _create_v1_path("/query/%s", query_type)

        content = await self.client.get_json(
            destination=destination,
            path=path,
            args=args,
            retry_on_dns_fail=retry_on_dns_fail,
            timeout=10000,
            ignore_backoff=ignore_backoff,
        )

        return content

    @log_function
    async def make_membership_event(
        self,
        destination: str,
        room_id: str,
        user_id: str,
        membership: str,
        params: Optional[Mapping[str, Union[str, Iterable[str]]]],
    ) -> JsonDict:
        """Asks a remote server to build and sign us a membership event

        Note that this does not append any events to any graphs.

        Args:
            destination (str): address of remote homeserver
            room_id (str): room to join/leave
            user_id (str): user to be joined/left
            membership (str): one of join/leave
            params (dict[str, str|Iterable[str]]): Query parameters to include in the
                request.

        Returns:
            Succeeds when we get a 2xx HTTP response. The result
            will be the decoded JSON body (ie, the new event).

            Fails with ``HTTPRequestException`` if we get an HTTP response
            code >= 300.

            Fails with ``NotRetryingDestination`` if we are not yet ready
            to retry this server.

            Fails with ``FederationDeniedError`` if the remote destination
            is not in our federation whitelist
        """
        valid_memberships = {Membership.JOIN, Membership.LEAVE, Membership.KNOCK}

        if membership not in valid_memberships:
            raise RuntimeError(
                "make_membership_event called with membership='%s', must be one of %s"
                % (membership, ",".join(valid_memberships))
            )
        path = _create_v1_path("/make_%s/%s/%s", membership, room_id, user_id)

        ignore_backoff = False
        retry_on_dns_fail = False

        if membership == Membership.LEAVE:
            # we particularly want to do our best to send leave events. The
            # problem is that if it fails, we won't retry it later, so if the
            # remote server was just having a momentary blip, the room will be
            # out of sync.
            ignore_backoff = True
            retry_on_dns_fail = True

        return await self.client.get_json(
            destination=destination,
            path=path,
            args=params,
            retry_on_dns_fail=retry_on_dns_fail,
            timeout=20000,
            ignore_backoff=ignore_backoff,
        )

    @log_function
    async def send_join_v1(
        self,
        room_version: RoomVersion,
        destination: str,
        room_id: str,
        event_id: str,
        content: JsonDict,
    ) -> "SendJoinResponse":
        path = _create_v1_path("/send_join/%s/%s", room_id, event_id)

        return await self.client.put_json(
            destination=destination,
            path=path,
            data=content,
            parser=SendJoinParser(room_version, v1_api=True),
            max_response_size=MAX_RESPONSE_SIZE_SEND_JOIN,
        )

    @log_function
    async def send_join_v2(
        self,
        room_version: RoomVersion,
        destination: str,
        room_id: str,
        event_id: str,
        content: JsonDict,
    ) -> "SendJoinResponse":
        path = _create_v2_path("/send_join/%s/%s", room_id, event_id)

        return await self.client.put_json(
            destination=destination,
            path=path,
            data=content,
            parser=SendJoinParser(room_version, v1_api=False),
            max_response_size=MAX_RESPONSE_SIZE_SEND_JOIN,
        )

    @log_function
    async def send_leave_v1(
        self, destination: str, room_id: str, event_id: str, content: JsonDict
    ) -> Tuple[int, JsonDict]:
        path = _create_v1_path("/send_leave/%s/%s", room_id, event_id)

        return await self.client.put_json(
            destination=destination,
            path=path,
            data=content,
            # we want to do our best to send this through. The problem is
            # that if it fails, we won't retry it later, so if the remote
            # server was just having a momentary blip, the room will be out of
            # sync.
            ignore_backoff=True,
        )

    @log_function
    async def send_leave_v2(
        self, destination: str, room_id: str, event_id: str, content: JsonDict
    ) -> JsonDict:
        path = _create_v2_path("/send_leave/%s/%s", room_id, event_id)

        return await self.client.put_json(
            destination=destination,
            path=path,
            data=content,
            # we want to do our best to send this through. The problem is
            # that if it fails, we won't retry it later, so if the remote
            # server was just having a momentary blip, the room will be out of
            # sync.
            ignore_backoff=True,
        )

    @log_function
    async def send_knock_v1(
        self,
        destination: str,
        room_id: str,
        event_id: str,
        content: JsonDict,
    ) -> JsonDict:
        """
        Sends a signed knock membership event to a remote server. This is the second
        step for knocking after make_knock.

        Args:
            destination: The remote homeserver.
            room_id: The ID of the room to knock on.
            event_id: The ID of the knock membership event that we're sending.
            content: The knock membership event that we're sending. Note that this is not the
                `content` field of the membership event, but the entire signed membership event
                itself represented as a JSON dict.

        Returns:
            The remote homeserver can optionally return some state from the room. The response
            dictionary is in the form:

            {"knock_state_events": [<state event dict>, ...]}

            The list of state events may be empty.
        """
        path = _create_v1_path("/send_knock/%s/%s", room_id, event_id)

        return await self.client.put_json(
            destination=destination, path=path, data=content
        )

    @log_function
    async def send_invite_v1(
        self, destination: str, room_id: str, event_id: str, content: JsonDict
    ) -> Tuple[int, JsonDict]:
        path = _create_v1_path("/invite/%s/%s", room_id, event_id)

        return await self.client.put_json(
            destination=destination, path=path, data=content, ignore_backoff=True
        )

    @log_function
    async def send_invite_v2(
        self, destination: str, room_id: str, event_id: str, content: JsonDict
    ) -> JsonDict:
        path = _create_v2_path("/invite/%s/%s", room_id, event_id)

        return await self.client.put_json(
            destination=destination, path=path, data=content, ignore_backoff=True
        )

    @log_function
    async def get_public_rooms(
        self,
        remote_server: str,
        limit: Optional[int] = None,
        since_token: Optional[str] = None,
        search_filter: Optional[Dict] = None,
        include_all_networks: bool = False,
        third_party_instance_id: Optional[str] = None,
    ) -> JsonDict:
        """Get the list of public rooms from a remote homeserver

        See synapse.federation.federation_client.FederationClient.get_public_rooms for
        more information.
        """
        if search_filter:
            # this uses MSC2197 (Search Filtering over Federation)
            path = _create_v1_path("/publicRooms")

            data: Dict[str, Any] = {
                "include_all_networks": "true" if include_all_networks else "false"
            }
            if third_party_instance_id:
                data["third_party_instance_id"] = third_party_instance_id
            if limit:
                data["limit"] = str(limit)
            if since_token:
                data["since"] = since_token

            data["filter"] = search_filter

            try:
                response = await self.client.post_json(
                    destination=remote_server, path=path, data=data, ignore_backoff=True
                )
            except HttpResponseException as e:
                if e.code == 403:
                    raise SynapseError(
                        403,
                        "You are not allowed to view the public rooms list of %s"
                        % (remote_server,),
                        errcode=Codes.FORBIDDEN,
                    )
                raise
        else:
            path = _create_v1_path("/publicRooms")

            args: Dict[str, Any] = {
                "include_all_networks": "true" if include_all_networks else "false"
            }
            if third_party_instance_id:
                args["third_party_instance_id"] = (third_party_instance_id,)
            if limit:
                args["limit"] = [str(limit)]
            if since_token:
                args["since"] = [since_token]

            try:
                response = await self.client.get_json(
                    destination=remote_server, path=path, args=args, ignore_backoff=True
                )
            except HttpResponseException as e:
                if e.code == 403:
                    raise SynapseError(
                        403,
                        "You are not allowed to view the public rooms list of %s"
                        % (remote_server,),
                        errcode=Codes.FORBIDDEN,
                    )
                raise

        return response

    @log_function
    async def exchange_third_party_invite(
        self, destination: str, room_id: str, event_dict: JsonDict
    ) -> JsonDict:
        path = _create_v1_path("/exchange_third_party_invite/%s", room_id)

        return await self.client.put_json(
            destination=destination, path=path, data=event_dict
        )

    @log_function
    async def get_event_auth(
        self, destination: str, room_id: str, event_id: str
    ) -> JsonDict:
        path = _create_v1_path("/event_auth/%s/%s", room_id, event_id)

        return await self.client.get_json(destination=destination, path=path)

    @log_function
    async def query_client_keys(
        self, destination: str, query_content: JsonDict, timeout: int
    ) -> JsonDict:
        """Query the device keys for a list of user ids hosted on a remote
        server.

        Request:
            {
              "device_keys": {
                "<user_id>": ["<device_id>"]
              }
            }

        Response:
            {
              "device_keys": {
                "<user_id>": {
                  "<device_id>": {...}
                }
              },
              "master_key": {
                "<user_id>": {...}
                }
              },
              "self_signing_key": {
                "<user_id>": {...}
              }
            }

        Args:
            destination: The server to query.
            query_content: The user ids to query.
        Returns:
            A dict containing device and cross-signing keys.
        """
        path = _create_v1_path("/user/keys/query")

        return await self.client.post_json(
            destination=destination, path=path, data=query_content, timeout=timeout
        )

    @log_function
    async def query_user_devices(
        self, destination: str, user_id: str, timeout: int
    ) -> JsonDict:
        """Query the devices for a user id hosted on a remote server.

        Response:
            {
              "stream_id": "...",
              "devices": [ { ... } ],
              "master_key": {
                "user_id": "<user_id>",
                "usage": [...],
                "keys": {...},
                "signatures": {
                  "<user_id>": {...}
                }
              },
              "self_signing_key": {
                "user_id": "<user_id>",
                "usage": [...],
                "keys": {...},
                "signatures": {
                  "<user_id>": {...}
                }
              }
            }

        Args:
            destination: The server to query.
            query_content: The user ids to query.
        Returns:
            A dict containing device and cross-signing keys.
        """
        path = _create_v1_path("/user/devices/%s", user_id)

        return await self.client.get_json(
            destination=destination, path=path, timeout=timeout
        )

    @log_function
    async def claim_client_keys(
        self, destination: str, query_content: JsonDict, timeout: int
    ) -> JsonDict:
        """Claim one-time keys for a list of devices hosted on a remote server.

        Request:
            {
              "one_time_keys": {
                "<user_id>": {
                  "<device_id>": "<algorithm>"
                }
              }
            }

        Response:
            {
              "device_keys": {
                "<user_id>": {
                  "<device_id>": {
                    "<algorithm>:<key_id>": "<key_base64>"
                  }
                }
              }
            }

        Args:
            destination: The server to query.
            query_content: The user ids to query.
        Returns:
            A dict containing the one-time keys.
        """

        path = _create_v1_path("/user/keys/claim")

        return await self.client.post_json(
            destination=destination, path=path, data=query_content, timeout=timeout
        )

    @log_function
    async def get_missing_events(
        self,
        destination: str,
        room_id: str,
        earliest_events: Iterable[str],
        latest_events: Iterable[str],
        limit: int,
        min_depth: int,
        timeout: int,
    ) -> JsonDict:
        path = _create_v1_path("/get_missing_events/%s", room_id)

        return await self.client.post_json(
            destination=destination,
            path=path,
            data={
                "limit": int(limit),
                "min_depth": int(min_depth),
                "earliest_events": earliest_events,
                "latest_events": latest_events,
            },
            timeout=timeout,
        )

    @log_function
    async def get_group_profile(
        self, destination: str, group_id: str, requester_user_id: str
    ) -> JsonDict:
        """Get a group profile"""
        path = _create_v1_path("/groups/%s/profile", group_id)

        return await self.client.get_json(
            destination=destination,
            path=path,
            args={"requester_user_id": requester_user_id},
            ignore_backoff=True,
        )

    @log_function
    async def update_group_profile(
        self, destination: str, group_id: str, requester_user_id: str, content: JsonDict
    ) -> JsonDict:
        """Update a remote group profile

        Args:
            destination
            group_id
            requester_user_id
            content: The new profile of the group
        """
        path = _create_v1_path("/groups/%s/profile", group_id)

        return self.client.post_json(
            destination=destination,
            path=path,
            args={"requester_user_id": requester_user_id},
            data=content,
            ignore_backoff=True,
        )

    @log_function
    async def get_group_summary(
        self, destination: str, group_id: str, requester_user_id: str
    ) -> JsonDict:
        """Get a group summary"""
        path = _create_v1_path("/groups/%s/summary", group_id)

        return await self.client.get_json(
            destination=destination,
            path=path,
            args={"requester_user_id": requester_user_id},
            ignore_backoff=True,
        )

    @log_function
    async def get_rooms_in_group(
        self, destination: str, group_id: str, requester_user_id: str
    ) -> JsonDict:
        """Get all rooms in a group"""
        path = _create_v1_path("/groups/%s/rooms", group_id)

        return await self.client.get_json(
            destination=destination,
            path=path,
            args={"requester_user_id": requester_user_id},
            ignore_backoff=True,
        )

    async def add_room_to_group(
        self,
        destination: str,
        group_id: str,
        requester_user_id: str,
        room_id: str,
        content: JsonDict,
    ) -> JsonDict:
        """Add a room to a group"""
        path = _create_v1_path("/groups/%s/room/%s", group_id, room_id)

        return await self.client.post_json(
            destination=destination,
            path=path,
            args={"requester_user_id": requester_user_id},
            data=content,
            ignore_backoff=True,
        )

    async def update_room_in_group(
        self,
        destination: str,
        group_id: str,
        requester_user_id: str,
        room_id: str,
        config_key: str,
        content: JsonDict,
    ) -> JsonDict:
        """Update room in group"""
        path = _create_v1_path(
            "/groups/%s/room/%s/config/%s", group_id, room_id, config_key
        )

        return await self.client.post_json(
            destination=destination,
            path=path,
            args={"requester_user_id": requester_user_id},
            data=content,
            ignore_backoff=True,
        )

    async def remove_room_from_group(
        self, destination: str, group_id: str, requester_user_id: str, room_id: str
    ) -> JsonDict:
        """Remove a room from a group"""
        path = _create_v1_path("/groups/%s/room/%s", group_id, room_id)

        return await self.client.delete_json(
            destination=destination,
            path=path,
            args={"requester_user_id": requester_user_id},
            ignore_backoff=True,
        )

    @log_function
    async def get_users_in_group(
        self, destination: str, group_id: str, requester_user_id: str
    ) -> JsonDict:
        """Get users in a group"""
        path = _create_v1_path("/groups/%s/users", group_id)

        return await self.client.get_json(
            destination=destination,
            path=path,
            args={"requester_user_id": requester_user_id},
            ignore_backoff=True,
        )

    @log_function
    async def get_invited_users_in_group(
        self, destination: str, group_id: str, requester_user_id: str
    ) -> JsonDict:
        """Get users that have been invited to a group"""
        path = _create_v1_path("/groups/%s/invited_users", group_id)

        return await self.client.get_json(
            destination=destination,
            path=path,
            args={"requester_user_id": requester_user_id},
            ignore_backoff=True,
        )

    @log_function
    async def accept_group_invite(
        self, destination: str, group_id: str, user_id: str, content: JsonDict
    ) -> JsonDict:
        """Accept a group invite"""
        path = _create_v1_path("/groups/%s/users/%s/accept_invite", group_id, user_id)

        return await self.client.post_json(
            destination=destination, path=path, data=content, ignore_backoff=True
        )

    @log_function
    def join_group(
        self, destination: str, group_id: str, user_id: str, content: JsonDict
    ) -> JsonDict:
        """Attempts to join a group"""
        path = _create_v1_path("/groups/%s/users/%s/join", group_id, user_id)

        return self.client.post_json(
            destination=destination, path=path, data=content, ignore_backoff=True
        )

    @log_function
    async def invite_to_group(
        self,
        destination: str,
        group_id: str,
        user_id: str,
        requester_user_id: str,
        content: JsonDict,
    ) -> JsonDict:
        """Invite a user to a group"""
        path = _create_v1_path("/groups/%s/users/%s/invite", group_id, user_id)

        return await self.client.post_json(
            destination=destination,
            path=path,
            args={"requester_user_id": requester_user_id},
            data=content,
            ignore_backoff=True,
        )

    @log_function
    async def invite_to_group_notification(
        self, destination: str, group_id: str, user_id: str, content: JsonDict
    ) -> JsonDict:
        """Sent by group server to inform a user's server that they have been
        invited.
        """

        path = _create_v1_path("/groups/local/%s/users/%s/invite", group_id, user_id)

        return await self.client.post_json(
            destination=destination, path=path, data=content, ignore_backoff=True
        )

    @log_function
    async def remove_user_from_group(
        self,
        destination: str,
        group_id: str,
        requester_user_id: str,
        user_id: str,
        content: JsonDict,
    ) -> JsonDict:
        """Remove a user from a group"""
        path = _create_v1_path("/groups/%s/users/%s/remove", group_id, user_id)

        return await self.client.post_json(
            destination=destination,
            path=path,
            args={"requester_user_id": requester_user_id},
            data=content,
            ignore_backoff=True,
        )

    @log_function
    async def remove_user_from_group_notification(
        self, destination: str, group_id: str, user_id: str, content: JsonDict
    ) -> JsonDict:
        """Sent by group server to inform a user's server that they have been
        kicked from the group.
        """

        path = _create_v1_path("/groups/local/%s/users/%s/remove", group_id, user_id)

        return await self.client.post_json(
            destination=destination, path=path, data=content, ignore_backoff=True
        )

    @log_function
    async def renew_group_attestation(
        self, destination: str, group_id: str, user_id: str, content: JsonDict
    ) -> JsonDict:
        """Sent by either a group server or a user's server to periodically update
        the attestations
        """

        path = _create_v1_path("/groups/%s/renew_attestation/%s", group_id, user_id)

        return await self.client.post_json(
            destination=destination, path=path, data=content, ignore_backoff=True
        )

    @log_function
    async def update_group_summary_room(
        self,
        destination: str,
        group_id: str,
        user_id: str,
        room_id: str,
        category_id: str,
        content: JsonDict,
    ) -> JsonDict:
        """Update a room entry in a group summary"""
        if category_id:
            path = _create_v1_path(
                "/groups/%s/summary/categories/%s/rooms/%s",
                group_id,
                category_id,
                room_id,
            )
        else:
            path = _create_v1_path("/groups/%s/summary/rooms/%s", group_id, room_id)

        return await self.client.post_json(
            destination=destination,
            path=path,
            args={"requester_user_id": user_id},
            data=content,
            ignore_backoff=True,
        )

    @log_function
    async def delete_group_summary_room(
        self,
        destination: str,
        group_id: str,
        user_id: str,
        room_id: str,
        category_id: str,
    ) -> JsonDict:
        """Delete a room entry in a group summary"""
        if category_id:
            path = _create_v1_path(
                "/groups/%s/summary/categories/%s/rooms/%s",
                group_id,
                category_id,
                room_id,
            )
        else:
            path = _create_v1_path("/groups/%s/summary/rooms/%s", group_id, room_id)

        return await self.client.delete_json(
            destination=destination,
            path=path,
            args={"requester_user_id": user_id},
            ignore_backoff=True,
        )

    @log_function
    async def get_group_categories(
        self, destination: str, group_id: str, requester_user_id: str
    ) -> JsonDict:
        """Get all categories in a group"""
        path = _create_v1_path("/groups/%s/categories", group_id)

        return await self.client.get_json(
            destination=destination,
            path=path,
            args={"requester_user_id": requester_user_id},
            ignore_backoff=True,
        )

    @log_function
    async def get_group_category(
        self, destination: str, group_id: str, requester_user_id: str, category_id: str
    ) -> JsonDict:
        """Get category info in a group"""
        path = _create_v1_path("/groups/%s/categories/%s", group_id, category_id)

        return await self.client.get_json(
            destination=destination,
            path=path,
            args={"requester_user_id": requester_user_id},
            ignore_backoff=True,
        )

    @log_function
    async def update_group_category(
        self,
        destination: str,
        group_id: str,
        requester_user_id: str,
        category_id: str,
        content: JsonDict,
    ) -> JsonDict:
        """Update a category in a group"""
        path = _create_v1_path("/groups/%s/categories/%s", group_id, category_id)

        return await self.client.post_json(
            destination=destination,
            path=path,
            args={"requester_user_id": requester_user_id},
            data=content,
            ignore_backoff=True,
        )

    @log_function
    async def delete_group_category(
        self, destination: str, group_id: str, requester_user_id: str, category_id: str
    ) -> JsonDict:
        """Delete a category in a group"""
        path = _create_v1_path("/groups/%s/categories/%s", group_id, category_id)

        return await self.client.delete_json(
            destination=destination,
            path=path,
            args={"requester_user_id": requester_user_id},
            ignore_backoff=True,
        )

    @log_function
    async def get_group_roles(
        self, destination: str, group_id: str, requester_user_id: str
    ) -> JsonDict:
        """Get all roles in a group"""
        path = _create_v1_path("/groups/%s/roles", group_id)

        return await self.client.get_json(
            destination=destination,
            path=path,
            args={"requester_user_id": requester_user_id},
            ignore_backoff=True,
        )

    @log_function
    async def get_group_role(
        self, destination: str, group_id: str, requester_user_id: str, role_id: str
    ) -> JsonDict:
        """Get a roles info"""
        path = _create_v1_path("/groups/%s/roles/%s", group_id, role_id)

        return await self.client.get_json(
            destination=destination,
            path=path,
            args={"requester_user_id": requester_user_id},
            ignore_backoff=True,
        )

    @log_function
    async def update_group_role(
        self,
        destination: str,
        group_id: str,
        requester_user_id: str,
        role_id: str,
        content: JsonDict,
    ) -> JsonDict:
        """Update a role in a group"""
        path = _create_v1_path("/groups/%s/roles/%s", group_id, role_id)

        return await self.client.post_json(
            destination=destination,
            path=path,
            args={"requester_user_id": requester_user_id},
            data=content,
            ignore_backoff=True,
        )

    @log_function
    async def delete_group_role(
        self, destination: str, group_id: str, requester_user_id: str, role_id: str
    ) -> JsonDict:
        """Delete a role in a group"""
        path = _create_v1_path("/groups/%s/roles/%s", group_id, role_id)

        return await self.client.delete_json(
            destination=destination,
            path=path,
            args={"requester_user_id": requester_user_id},
            ignore_backoff=True,
        )

    @log_function
    async def update_group_summary_user(
        self,
        destination: str,
        group_id: str,
        requester_user_id: str,
        user_id: str,
        role_id: str,
        content: JsonDict,
    ) -> JsonDict:
        """Update a users entry in a group"""
        if role_id:
            path = _create_v1_path(
                "/groups/%s/summary/roles/%s/users/%s", group_id, role_id, user_id
            )
        else:
            path = _create_v1_path("/groups/%s/summary/users/%s", group_id, user_id)

        return await self.client.post_json(
            destination=destination,
            path=path,
            args={"requester_user_id": requester_user_id},
            data=content,
            ignore_backoff=True,
        )

    @log_function
    async def set_group_join_policy(
        self, destination: str, group_id: str, requester_user_id: str, content: JsonDict
    ) -> JsonDict:
        """Sets the join policy for a group"""
        path = _create_v1_path("/groups/%s/settings/m.join_policy", group_id)

        return await self.client.put_json(
            destination=destination,
            path=path,
            args={"requester_user_id": requester_user_id},
            data=content,
            ignore_backoff=True,
        )

    @log_function
    async def delete_group_summary_user(
        self,
        destination: str,
        group_id: str,
        requester_user_id: str,
        user_id: str,
        role_id: str,
    ) -> JsonDict:
        """Delete a users entry in a group"""
        if role_id:
            path = _create_v1_path(
                "/groups/%s/summary/roles/%s/users/%s", group_id, role_id, user_id
            )
        else:
            path = _create_v1_path("/groups/%s/summary/users/%s", group_id, user_id)

        return await self.client.delete_json(
            destination=destination,
            path=path,
            args={"requester_user_id": requester_user_id},
            ignore_backoff=True,
        )

    async def bulk_get_publicised_groups(
        self, destination: str, user_ids: Iterable[str]
    ) -> JsonDict:
        """Get the groups a list of users are publicising"""

        path = _create_v1_path("/get_groups_publicised")

        content = {"user_ids": user_ids}

        return await self.client.post_json(
            destination=destination, path=path, data=content, ignore_backoff=True
        )

    async def get_room_complexity(self, destination: str, room_id: str) -> JsonDict:
        """
        Args:
            destination: The remote server
            room_id: The room ID to ask about.
        """
        path = _create_path(FEDERATION_UNSTABLE_PREFIX, "/rooms/%s/complexity", room_id)

        return await self.client.get_json(destination=destination, path=path)

    async def get_space_summary(
        self,
        destination: str,
        room_id: str,
        suggested_only: bool,
        max_rooms_per_space: Optional[int],
        exclude_rooms: List[str],
    ) -> JsonDict:
        """
        Args:
            destination: The remote server
            room_id: The room ID to ask about.
            suggested_only: if True, only suggested rooms will be returned
            max_rooms_per_space: an optional limit to the number of children to be
               returned per space
            exclude_rooms: a list of any rooms we can skip
        """
        # TODO When switching to the stable endpoint, use GET instead of POST.
        path = _create_path(
            FEDERATION_UNSTABLE_PREFIX, "/org.matrix.msc2946/spaces/%s", room_id
        )

        params = {
            "suggested_only": suggested_only,
            "exclude_rooms": exclude_rooms,
        }
        if max_rooms_per_space is not None:
            params["max_rooms_per_space"] = max_rooms_per_space

        return await self.client.post_json(
            destination=destination, path=path, data=params
        )


def _create_path(federation_prefix: str, path: str, *args: str) -> str:
    """
    Ensures that all args are url encoded.
    """
    return federation_prefix + path % tuple(urllib.parse.quote(arg, "") for arg in args)


def _create_v1_path(path: str, *args: str) -> str:
    """Creates a path against V1 federation API from the path template and
    args. Ensures that all args are url encoded.

    Example:

        _create_v1_path("/event/%s", event_id)

    Args:
        path: String template for the path
        args: Args to insert into path. Each arg will be url encoded
    """
    return _create_path(FEDERATION_V1_PREFIX, path, *args)


def _create_v2_path(path: str, *args: str) -> str:
    """Creates a path against V2 federation API from the path template and
    args. Ensures that all args are url encoded.

    Example:

        _create_v2_path("/event/%s", event_id)

    Args:
        path: String template for the path
        args: Args to insert into path. Each arg will be url encoded
    """
    return _create_path(FEDERATION_V2_PREFIX, path, *args)


@attr.s(slots=True, auto_attribs=True)
class SendJoinResponse:
    """The parsed response of a `/send_join` request."""

    # The list of auth events from the /send_join response.
    auth_events: List[EventBase]
    # The list of state from the /send_join response.
    state: List[EventBase]
    # The raw join event from the /send_join response.
    event_dict: JsonDict
    # The parsed join event from the /send_join response. This will be None if
    # "event" is not included in the response.
    event: Optional[EventBase] = None


@ijson.coroutine
def _event_parser(event_dict: JsonDict):
    """Helper function for use with `ijson.kvitems_coro` to parse key-value pairs
    to add them to a given dictionary.
    """

    while True:
        key, value = yield
        event_dict[key] = value


@ijson.coroutine
def _event_list_parser(room_version: RoomVersion, events: List[EventBase]):
    """Helper function for use with `ijson.items_coro` to parse an array of
    events and add them to the given list.
    """

    while True:
        obj = yield
        event = make_event_from_dict(obj, room_version)
        events.append(event)


class SendJoinParser(ByteParser[SendJoinResponse]):
    """A parser for the response to `/send_join` requests.

    Args:
        room_version: The version of the room.
        v1_api: Whether the response is in the v1 format.
    """

    CONTENT_TYPE = "application/json"

    def __init__(self, room_version: RoomVersion, v1_api: bool):
        self._response = SendJoinResponse([], [], {})
        self._room_version = room_version

        # The V1 API has the shape of `[200, {...}]`, which we handle by
        # prefixing with `item.*`.
        prefix = "item." if v1_api else ""

        self._coro_state = ijson.items_coro(
            _event_list_parser(room_version, self._response.state),
            prefix + "state.item",
        )
        self._coro_auth = ijson.items_coro(
            _event_list_parser(room_version, self._response.auth_events),
            prefix + "auth_chain.item",
        )
        self._coro_event = ijson.kvitems_coro(
            _event_parser(self._response.event_dict),
            prefix + "org.matrix.msc3083.v2.event",
        )

    def write(self, data: bytes) -> int:
        self._coro_state.send(data)
        self._coro_auth.send(data)
        self._coro_event.send(data)

        return len(data)

    def finish(self) -> SendJoinResponse:
        if self._response.event_dict:
            self._response.event = make_event_from_dict(
                self._response.event_dict, self._room_version
            )
        return self._response