dendrite/common/events.go
2020-03-20 10:42:11 +00:00

109 lines
3.1 KiB
Go

// Copyright 2017 Vector Creations Ltd
//
// 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 common
import (
"context"
"errors"
"fmt"
"time"
"github.com/matrix-org/dendrite/common/config"
"github.com/matrix-org/dendrite/roomserver/api"
"github.com/matrix-org/gomatrixserverlib"
"github.com/matrix-org/util"
)
// ErrRoomNoExists is returned when trying to lookup the state of a room that
// doesn't exist
var ErrRoomNoExists = errors.New("Room does not exist")
// BuildEvent builds a Matrix event using the event builder and roomserver query
// API client provided. If also fills roomserver query API response (if provided)
// in case the function calling FillBuilder needs to use it.
// Returns ErrRoomNoExists if the state of the room could not be retrieved because
// the room doesn't exist
// Returns an error if something else went wrong
func BuildEvent(
ctx context.Context,
builder *gomatrixserverlib.EventBuilder, cfg *config.Dendrite, evTime time.Time,
queryAPI api.RoomserverQueryAPI, queryRes *api.QueryLatestEventsAndStateResponse,
) (*gomatrixserverlib.Event, error) {
err := AddPrevEventsToEvent(ctx, builder, queryAPI, queryRes)
if err != nil {
return nil, err
}
eventID := fmt.Sprintf("$%s:%s", util.RandomString(16), cfg.Matrix.ServerName)
event, err := builder.Build(
eventID, evTime, cfg.Matrix.ServerName, cfg.Matrix.KeyID,
cfg.Matrix.PrivateKey, queryRes.RoomVersion,
)
if err != nil {
return nil, err
}
return &event, nil
}
// AddPrevEventsToEvent fills out the prev_events and auth_events fields in builder
func AddPrevEventsToEvent(
ctx context.Context,
builder *gomatrixserverlib.EventBuilder,
queryAPI api.RoomserverQueryAPI, queryRes *api.QueryLatestEventsAndStateResponse,
) error {
eventsNeeded, err := gomatrixserverlib.StateNeededForEventBuilder(builder)
if err != nil {
return err
}
// Ask the roomserver for information about this room
queryReq := api.QueryLatestEventsAndStateRequest{
RoomID: builder.RoomID,
StateToFetch: eventsNeeded.Tuples(),
}
if queryRes == nil {
queryRes = &api.QueryLatestEventsAndStateResponse{}
}
if err = queryAPI.QueryLatestEventsAndState(ctx, &queryReq, queryRes); err != nil {
return err
}
if !queryRes.RoomExists {
return ErrRoomNoExists
}
builder.Depth = queryRes.Depth
builder.PrevEvents = queryRes.LatestEvents
authEvents := gomatrixserverlib.NewAuthEvents(nil)
for i := range queryRes.StateEvents {
err = authEvents.AddEvent(&queryRes.StateEvents[i].Event)
if err != nil {
return err
}
}
refs, err := eventsNeeded.AuthEventReferences(&authEvents)
if err != nil {
return err
}
builder.AuthEvents = refs
return nil
}