package mautrix import ( "encoding/json" "fmt" "runtime/debug" "time" ) // Syncer represents an interface that must be satisfied in order to do /sync requests on a client. type Syncer interface { // Process the /sync response. The since parameter is the since= value that was used to produce the response. // This is useful for detecting the very first sync (since=""). If an error is return, Syncing will be stopped // permanently. ProcessResponse(resp *RespSync, since string) error // OnFailedSync returns either the time to wait before retrying or an error to stop syncing permanently. OnFailedSync(res *RespSync, err error) (time.Duration, error) // GetFilterJSON for the given user ID. NOT the filter ID. GetFilterJSON(userID string) json.RawMessage } // DefaultSyncer is the default syncing implementation. You can either write your own syncer, or selectively // replace parts of this default syncer (e.g. the ProcessResponse method). The default syncer uses the observer // pattern to notify callers about incoming events. See DefaultSyncer.OnEventType for more information. type DefaultSyncer struct { UserID string Store Storer listeners map[EventType][]OnEventListener // event type to listeners array } // OnEventListener can be used with DefaultSyncer.OnEventType to be informed of incoming events. type OnEventListener func(*Event) // NewDefaultSyncer returns an instantiated DefaultSyncer func NewDefaultSyncer(userID string, store Storer) *DefaultSyncer { return &DefaultSyncer{ UserID: userID, Store: store, listeners: make(map[EventType][]OnEventListener), } } // ProcessResponse processes the /sync response in a way suitable for bots. "Suitable for bots" means a stream of // unrepeating events. Returns a fatal error if a listener panics. func (s *DefaultSyncer) ProcessResponse(res *RespSync, since string) (err error) { if !s.shouldProcessResponse(res, since) { return } defer func() { if r := recover(); r != nil { err = fmt.Errorf("ProcessResponse panicked! userID=%s since=%s panic=%s\n%s", s.UserID, since, r, debug.Stack()) } }() for roomID, roomData := range res.Rooms.Join { room := s.getOrCreateRoom(roomID) for _, event := range roomData.State.Events { event.RoomID = roomID room.UpdateState(event) s.notifyListeners(event) } for _, event := range roomData.Timeline.Events { event.RoomID = roomID s.notifyListeners(event) } } for roomID, roomData := range res.Rooms.Invite { room := s.getOrCreateRoom(roomID) for _, event := range roomData.State.Events { event.RoomID = roomID room.UpdateState(event) s.notifyListeners(event) } } for roomID, roomData := range res.Rooms.Leave { room := s.getOrCreateRoom(roomID) for _, event := range roomData.Timeline.Events { if event.StateKey != nil { event.RoomID = roomID room.UpdateState(event) s.notifyListeners(event) } } } return } // OnEventType allows callers to be notified when there are new events for the given event type. // There are no duplicate checks. func (s *DefaultSyncer) OnEventType(eventType EventType, callback OnEventListener) { _, exists := s.listeners[eventType] if !exists { s.listeners[eventType] = []OnEventListener{} } s.listeners[eventType] = append(s.listeners[eventType], callback) } // shouldProcessResponse returns true if the response should be processed. May modify the response to remove // stuff that shouldn't be processed. func (s *DefaultSyncer) shouldProcessResponse(resp *RespSync, since string) bool { if since == "" { return false } // This is a horrible hack because /sync will return the most recent messages for a room // as soon as you /join it. We do NOT want to process those events in that particular room // because they may have already been processed (if you toggle the bot in/out of the room). // // Work around this by inspecting each room's timeline and seeing if an m.room.member event for us // exists and is "join" and then discard processing that room entirely if so. // TODO: We probably want to process messages from after the last join event in the timeline. for roomID, roomData := range resp.Rooms.Join { for i := len(roomData.Timeline.Events) - 1; i >= 0; i-- { e := roomData.Timeline.Events[i] if e.Type == StateMember && e.GetStateKey() == s.UserID { if e.Content.Membership == "join" { _, ok := resp.Rooms.Join[roomID] if !ok { continue } delete(resp.Rooms.Join, roomID) // don't re-process messages delete(resp.Rooms.Invite, roomID) // don't re-process invites break } } } } return true } // getOrCreateRoom must only be called by the Sync() goroutine which calls ProcessResponse() func (s *DefaultSyncer) getOrCreateRoom(roomID string) *Room { room := s.Store.LoadRoom(roomID) if room == nil { // create a new Room room = NewRoom(roomID) s.Store.SaveRoom(room) } return room } func (s *DefaultSyncer) notifyListeners(event *Event) { listeners, exists := s.listeners[event.Type] if !exists { return } for _, fn := range listeners { fn(event) } } // OnFailedSync always returns a 10 second wait period between failed /syncs, never a fatal error. func (s *DefaultSyncer) OnFailedSync(res *RespSync, err error) (time.Duration, error) { return 10 * time.Second, nil } // GetFilterJSON returns a filter with a timeline limit of 50. func (s *DefaultSyncer) GetFilterJSON(userID string) json.RawMessage { return json.RawMessage(`{"room":{"timeline":{"limit":50}}}`) }