dendrite/roomserver/internal/perform/perform_leave.go

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// Copyright 2020 The Matrix.org Foundation C.I.C.
//
// 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.
package perform
import (
"context"
"fmt"
"strings"
fsAPI "github.com/matrix-org/dendrite/federationapi/api"
"github.com/matrix-org/dendrite/roomserver/api"
"github.com/matrix-org/dendrite/roomserver/internal/helpers"
"github.com/matrix-org/dendrite/roomserver/internal/input"
"github.com/matrix-org/dendrite/roomserver/storage"
"github.com/matrix-org/dendrite/setup/config"
"github.com/matrix-org/gomatrixserverlib"
"github.com/matrix-org/util"
)
type Leaver struct {
Cfg *config.RoomServer
DB storage.Database
FSAPI fsAPI.FederationInternalAPI
Inputer *input.Inputer
}
// WriteOutputEvents implements OutputRoomEventWriter
func (r *Leaver) PerformLeave(
ctx context.Context,
req *api.PerformLeaveRequest,
res *api.PerformLeaveResponse,
) ([]api.OutputEvent, error) {
_, domain, err := gomatrixserverlib.SplitID('@', req.UserID)
if err != nil {
return nil, fmt.Errorf("supplied user ID %q in incorrect format", req.UserID)
}
if domain != r.Cfg.Matrix.ServerName {
return nil, fmt.Errorf("user %q does not belong to this homeserver", req.UserID)
}
if strings.HasPrefix(req.RoomID, "!") {
return r.performLeaveRoomByID(ctx, req, res)
}
return nil, fmt.Errorf("room ID %q is invalid", req.RoomID)
}
func (r *Leaver) performLeaveRoomByID(
ctx context.Context,
req *api.PerformLeaveRequest,
res *api.PerformLeaveResponse, // nolint:unparam
) ([]api.OutputEvent, error) {
// If there's an invite outstanding for the room then respond to
// that.
isInvitePending, senderUser, eventID, err := helpers.IsInvitePending(ctx, r.DB, req.RoomID, req.UserID)
if err == nil && isInvitePending {
var host gomatrixserverlib.ServerName
_, host, err = gomatrixserverlib.SplitID('@', senderUser)
if err != nil {
return nil, fmt.Errorf("sender %q is invalid", senderUser)
}
if host != r.Cfg.Matrix.ServerName {
return r.performFederatedRejectInvite(ctx, req, res, senderUser, eventID)
}
}
// There's no invite pending, so first of all we want to find out
// if the room exists and if the user is actually in it.
latestReq := api.QueryLatestEventsAndStateRequest{
RoomID: req.RoomID,
StateToFetch: []gomatrixserverlib.StateKeyTuple{
{
EventType: gomatrixserverlib.MRoomMember,
StateKey: req.UserID,
},
},
}
latestRes := api.QueryLatestEventsAndStateResponse{}
if err = helpers.QueryLatestEventsAndState(ctx, r.DB, &latestReq, &latestRes); err != nil {
return nil, err
}
if !latestRes.RoomExists {
return nil, fmt.Errorf("room %q does not exist", req.RoomID)
}
// Now let's see if the user is in the room.
if len(latestRes.StateEvents) == 0 {
return nil, fmt.Errorf("user %q is not a member of room %q", req.UserID, req.RoomID)
}
membership, err := latestRes.StateEvents[0].Membership()
if err != nil {
return nil, fmt.Errorf("error getting membership: %w", err)
}
if membership != gomatrixserverlib.Join && membership != gomatrixserverlib.Invite {
return nil, fmt.Errorf("user %q is not joined to the room (membership is %q)", req.UserID, membership)
}
// Prepare the template for the leave event.
userID := req.UserID
eb := gomatrixserverlib.EventBuilder{
Type: gomatrixserverlib.MRoomMember,
Sender: userID,
StateKey: &userID,
RoomID: req.RoomID,
Redacts: "",
}
if err = eb.SetContent(map[string]interface{}{"membership": "leave"}); err != nil {
return nil, fmt.Errorf("eb.SetContent: %w", err)
}
if err = eb.SetUnsigned(struct{}{}); err != nil {
return nil, fmt.Errorf("eb.SetUnsigned: %w", err)
}
// We know that the user is in the room at this point so let's build
// a leave event.
// TODO: Check what happens if the room exists on the server
// but everyone has since left. I suspect it does the wrong thing.
event, buildRes, err := buildEvent(ctx, r.DB, r.Cfg.Matrix, &eb)
if err != nil {
return nil, fmt.Errorf("eventutil.BuildEvent: %w", err)
}
// Give our leave event to the roomserver input stream. The
// roomserver will process the membership change and notify
// downstream automatically.
inputReq := api.InputRoomEventsRequest{
InputRoomEvents: []api.InputRoomEvent{
{
Kind: api.KindNew,
Event: event.Headered(buildRes.RoomVersion),
AuthEventIDs: event.AuthEventIDs(),
SendAsServer: string(r.Cfg.Matrix.ServerName),
},
},
}
inputRes := api.InputRoomEventsResponse{}
r.Inputer.InputRoomEvents(ctx, &inputReq, &inputRes)
if err = inputRes.Err(); err != nil {
return nil, fmt.Errorf("r.InputRoomEvents: %w", err)
}
return nil, nil
}
func (r *Leaver) performFederatedRejectInvite(
ctx context.Context,
req *api.PerformLeaveRequest,
res *api.PerformLeaveResponse, // nolint:unparam
senderUser, eventID string,
) ([]api.OutputEvent, error) {
_, domain, err := gomatrixserverlib.SplitID('@', senderUser)
if err != nil {
return nil, fmt.Errorf("user ID %q invalid: %w", senderUser, err)
}
// Ask the federation sender to perform a federated leave for us.
leaveReq := fsAPI.PerformLeaveRequest{
RoomID: req.RoomID,
UserID: req.UserID,
ServerNames: []gomatrixserverlib.ServerName{domain},
}
leaveRes := fsAPI.PerformLeaveResponse{}
if err := r.FSAPI.PerformLeave(ctx, &leaveReq, &leaveRes); err != nil {
// failures in PerformLeave should NEVER stop us from telling other components like the
// sync API that the invite was withdrawn. Otherwise we can end up with stuck invites.
util.GetLogger(ctx).WithError(err).Errorf("failed to PerformLeave, still retiring invite event")
}
// Withdraw the invite, so that the sync API etc are
// notified that we rejected it.
return []api.OutputEvent{
{
Type: api.OutputTypeRetireInviteEvent,
RetireInviteEvent: &api.OutputRetireInviteEvent{
EventID: eventID,
Membership: "leave",
TargetUserID: req.UserID,
},
},
}, nil
}