Function GetMissingEvents

federationapi/routing/missingevents.go:34–78

GetMissingEvents returns missing events between earliest_events & latest_events. Events are fetched from room DAG starting from latest_events until we reach earliest_events or the limit.

(
	httpReq *http.Request,
	request *gomatrixserverlib.FederationRequest,
	rsAPI api.FederationRoomserverAPI,
	roomID string,
)

// GetMissingEvents returns missing events between earliest_events & latest_events.
// Events are fetched from room DAG starting from latest_events until we reach earliest_events or the limit.
func GetMissingEvents(
	httpReq *http.Request,
	request *gomatrixserverlib.FederationRequest,
	rsAPI api.FederationRoomserverAPI,
	roomID string,
) util.JSONResponse {
	var gme getMissingEventRequest
	if err := json.Unmarshal(request.Content(), &gme); err != nil {
		return util.JSONResponse{
			Code: http.StatusBadRequest,
			JSON: jsonerror.NotJSON("The request body could not be decoded into valid JSON. " + err.Error()),
		}
	}

	// If we don't think we belong to this room then don't waste the effort
	// responding to expensive requests for it.
	if err := ErrorIfLocalServerNotInRoom(httpReq.Context(), rsAPI, roomID); err != nil {
		return *err
	}

	var eventsResponse api.QueryMissingEventsResponse
	if err := rsAPI.QueryMissingEvents(
		httpReq.Context(), &api.QueryMissingEventsRequest{
			EarliestEvents: gme.EarliestEvents,
			LatestEvents:   gme.LatestEvents,
			Limit:          gme.Limit,
			ServerName:     request.Origin(),
		},
		&eventsResponse,
	); err != nil {
		util.GetLogger(httpReq.Context()).WithError(err).Error("query.QueryMissingEvents failed")
		return jsonerror.InternalServerError()
	}

	eventsResponse.Events = filterEvents(eventsResponse.Events, roomID)

	resp := gomatrixserverlib.RespMissingEvents{
		Events: gomatrixserverlib.NewEventJSONsFromHeaderedEvents(eventsResponse.Events),
	}

	return util.JSONResponse{
		Code: http.StatusOK,
		JSON: resp,
	}
}

// filterEvents returns only those events with matching roomID
func filterEvents(