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// Copyright 2017 Vector Creations Ltd
// Copyright 2018 New Vector Ltd
// Copyright 2019-2020 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 input
import (
"context"
"fmt"
"github.com/matrix-org/dendrite/common"
"github.com/matrix-org/dendrite/roomserver/api"
"github.com/matrix-org/dendrite/roomserver/state"
"github.com/matrix-org/dendrite/roomserver/storage"
"github.com/matrix-org/dendrite/roomserver/types"
"github.com/matrix-org/gomatrixserverlib"
log "github.com/sirupsen/logrus"
)
// OutputRoomEventWriter has the APIs needed to write an event to the output logs.
type OutputRoomEventWriter interface {
// Write a list of events for a room
WriteOutputEvents(roomID string, updates []api.OutputEvent) error
}
// processRoomEvent can only be called once at a time
//
// TODO(#375): This should be rewritten to allow concurrent calls. The
// difficulty is in ensuring that we correctly annotate events with the correct
// state deltas when sending to kafka streams
func processRoomEvent(
ctx context.Context,
db storage.Database,
ow OutputRoomEventWriter,
input api.InputRoomEvent,
) (eventID string, err error) {
// Parse and validate the event JSON
headered := input.Event
event := headered.Unwrap()
// Check that the event passes authentication checks and work out the numeric IDs for the auth events.
authEventNIDs, err := checkAuthEvents(ctx, db, headered, input.AuthEventIDs)
if err != nil {
return
}
if input.TransactionID != nil {
tdID := input.TransactionID
eventID, err = db.GetTransactionEventID(
ctx, tdID.TransactionID, tdID.SessionID, event.Sender(),
)
// On error OR event with the transaction already processed/processesing
if err != nil || eventID != "" {
return
}
}
// Store the event
roomNID, stateAtEvent, err := db.StoreEvent(ctx, event, input.TransactionID, authEventNIDs)
if err != nil {
return
}
if input.Kind == api.KindOutlier {
// For outliers we can stop after we've stored the event itself as it
// doesn't have any associated state to store and we don't need to
// notify anyone about it.
return event.EventID(), nil
}
if stateAtEvent.BeforeStateSnapshotNID == 0 {
// We haven't calculated a state for this event yet.
// Lets calculate one.
err = calculateAndSetState(ctx, db, input, roomNID, &stateAtEvent, event)
if err != nil {
return
}
}
if input.Kind == api.KindBackfill {
// Backfill is not implemented.
panic("Not implemented")
}
// Update the extremities of the event graph for the room
return event.EventID(), updateLatestEvents(
ctx, db, ow, roomNID, stateAtEvent, event, input.SendAsServer, input.TransactionID,
)
}
func calculateAndSetState(
ctx context.Context,
db storage.Database,
input api.InputRoomEvent,
roomNID types.RoomNID,
stateAtEvent *types.StateAtEvent,
event gomatrixserverlib.Event,
) error {
var err error
roomState := state.NewStateResolution(db)
if input.HasState {
// We've been told what the state at the event is so we don't need to calculate it.
// Check that those state events are in the database and store the state.
var entries []types.StateEntry
if entries, err = db.StateEntriesForEventIDs(ctx, input.StateEventIDs); err != nil {
return err
}
if stateAtEvent.BeforeStateSnapshotNID, err = db.AddState(ctx, roomNID, nil, entries); err != nil {
return err
}
} else {
// We haven't been told what the state at the event is so we need to calculate it from the prev_events
if stateAtEvent.BeforeStateSnapshotNID, err = roomState.CalculateAndStoreStateBeforeEvent(ctx, event, roomNID); err != nil {
return err
}
}
return db.SetState(ctx, stateAtEvent.EventNID, stateAtEvent.BeforeStateSnapshotNID)
}
func processInviteEvent(
ctx context.Context,
db storage.Database,
ow OutputRoomEventWriter,
input api.InputInviteEvent,
) (err error) {
if input.Event.StateKey() == nil {
return fmt.Errorf("invite must be a state event")
}
roomID := input.Event.RoomID()
targetUserID := *input.Event.StateKey()
log.WithFields(log.Fields{
"event_id": input.Event.EventID(),
"room_id": roomID,
"room_version": input.RoomVersion,
"target_user_id": targetUserID,
}).Info("processing invite event")
updater, err := db.MembershipUpdater(ctx, roomID, targetUserID, input.RoomVersion)
if err != nil {
return err
}
succeeded := false
defer func() {
txerr := common.EndTransaction(updater, &succeeded)
if err == nil && txerr != nil {
err = txerr
}
}()
if updater.IsJoin() {
// If the user is joined to the room then that takes precedence over this
// invite event. It makes little sense to move a user that is already
// joined to the room into the invite state.
// This could plausibly happen if an invite request raced with a join
// request for a user. For example if a user was invited to a public
// room and they joined the room at the same time as the invite was sent.
// The other way this could plausibly happen is if an invite raced with
// a kick. For example if a user was kicked from a room in error and in
// response someone else in the room re-invited them then it is possible
// for the invite request to race with the leave event so that the
// target receives invite before it learns that it has been kicked.
// There are a few ways this could be plausibly handled in the roomserver.
// 1) Store the invite, but mark it as retired. That will result in the
// permanent rejection of that invite event. So even if the target
// user leaves the room and the invite is retransmitted it will be
// ignored. However a new invite with a new event ID would still be
// accepted.
// 2) Silently discard the invite event. This means that if the event
// was retransmitted at a later date after the target user had left
// the room we would accept the invite. However since we hadn't told
// the sending server that the invite had been discarded it would
// have no reason to attempt to retry.
// 3) Signal the sending server that the user is already joined to the
// room.
// For now we will implement option 2. Since in the abesence of a retry
// mechanism it will be equivalent to option 1, and we don't have a
// signalling mechanism to implement option 3.
return nil
}
event := input.Event.Unwrap()
if len(input.InviteRoomState) > 0 {
// If we were supplied with some invite room state already (which is
// most likely to be if the event came in over federation) then use
// that.
if err = event.SetUnsignedField("invite_room_state", input.InviteRoomState); err != nil {
return err
}
} else {
// There's no invite room state, so let's have a go at building it
// up from local data (which is most likely to be if the event came
// from the CS API). If we know about the room then we can insert
// the invite room state, if we don't then we just fail quietly.
if irs, ierr := buildInviteStrippedState(ctx, db, input); ierr == nil {
if err = event.SetUnsignedField("invite_room_state", irs); err != nil {
return err
}
}
}
outputUpdates, err := updateToInviteMembership(updater, &event, nil, input.Event.RoomVersion)
if err != nil {
return err
}
if err = ow.WriteOutputEvents(roomID, outputUpdates); err != nil {
return err
}
succeeded = true
return nil
}
func buildInviteStrippedState(
ctx context.Context,
db storage.Database,
input api.InputInviteEvent,
) ([]gomatrixserverlib.InviteV2StrippedState, error) {
roomNID, err := db.RoomNID(ctx, input.Event.RoomID())
if err != nil || roomNID == 0 {
return nil, fmt.Errorf("room %q unknown", input.Event.RoomID())
}
stateWanted := []gomatrixserverlib.StateKeyTuple{}
for _, t := range []string{
gomatrixserverlib.MRoomName, gomatrixserverlib.MRoomCanonicalAlias,
gomatrixserverlib.MRoomAliases, gomatrixserverlib.MRoomJoinRules,
} {
stateWanted = append(stateWanted, gomatrixserverlib.StateKeyTuple{
EventType: t,
StateKey: "",
})
}
_, currentStateSnapshotNID, _, err := db.LatestEventIDs(ctx, roomNID)
if err != nil {
return nil, err
}
roomState := state.NewStateResolution(db)
stateEntries, err := roomState.LoadStateAtSnapshotForStringTuples(
ctx, currentStateSnapshotNID, stateWanted,
)
if err != nil {
return nil, err
}
stateNIDs := []types.EventNID{}
for _, stateNID := range stateEntries {
stateNIDs = append(stateNIDs, stateNID.EventNID)
}
stateEvents, err := db.Events(ctx, stateNIDs)
if err != nil {
return nil, err
}
inviteState := []gomatrixserverlib.InviteV2StrippedState{
gomatrixserverlib.NewInviteV2StrippedState(&input.Event.Event),
}
for _, event := range stateEvents {
inviteState = append(inviteState, gomatrixserverlib.NewInviteV2StrippedState(&event.Event))
}
return inviteState, nil
}
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