2024-02-27 16:12:04 +01:00

137 lines
3.8 KiB

* Standalone signaling server for the Nextcloud Spreed app.
* Copyright (C) 2017 struktur AG
* @author Joachim Bauch <>
* @license GNU AGPL version 3 or any later version
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* GNU Affero General Public License for more details.
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <>.
package signaling
import (
const (
initialConnectInterval = time.Second
maxConnectInterval = 8 * time.Second
NatsLoopbackUrl = "nats://loopback"
type NatsSubscription interface {
Unsubscribe() error
type NatsClient interface {
Subscribe(subject string, ch chan *nats.Msg) (NatsSubscription, error)
Publish(subject string, message interface{}) error
Decode(msg *nats.Msg, v interface{}) error
// The NATS client doesn't work if a subject contains spaces. As the room id
// can have an arbitrary format, we need to make sure the subject is valid.
// See "" for a similar report.
func GetEncodedSubject(prefix string, suffix string) string {
return prefix + "." + base64.StdEncoding.EncodeToString([]byte(suffix))
type natsClient struct {
nc *nats.Conn
conn *nats.EncodedConn
func NewNatsClient(url string) (NatsClient, error) {
if url == ":loopback:" {
log.Printf("WARNING: events url %s is deprecated, please use %s instead", url, NatsLoopbackUrl)
url = NatsLoopbackUrl
if url == NatsLoopbackUrl {
log.Println("Using internal NATS loopback client")
return NewLoopbackNatsClient()
backoff, err := NewExponentialBackoff(initialConnectInterval, maxConnectInterval)
if err != nil {
return nil, err
client := &natsClient{}, err = nats.Connect(url,
ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt)
defer stop()
// The initial connect must succeed, so we retry in the case of an error.
for err != nil {
log.Printf("Could not create connection (%s), will retry in %s", err, backoff.NextWait())
if ctx.Err() != nil {
return nil, fmt.Errorf("interrupted")
}, err = nats.Connect(url)
log.Printf("Connection established to %s (%s)",,
// All communication will be JSON based.
client.conn, _ = nats.NewEncodedConn(, nats.JSON_ENCODER)
return client, nil
func (c *natsClient) Close() {
func (c *natsClient) onClosed(conn *nats.Conn) {
log.Println("NATS client closed", conn.LastError())
func (c *natsClient) onDisconnected(conn *nats.Conn) {
log.Println("NATS client disconnected")
func (c *natsClient) onReconnected(conn *nats.Conn) {
log.Printf("NATS client reconnected to %s (%s)", conn.ConnectedUrl(), conn.ConnectedServerId())
func (c *natsClient) Subscribe(subject string, ch chan *nats.Msg) (NatsSubscription, error) {
return, ch)
func (c *natsClient) Publish(subject string, message interface{}) error {
return c.conn.Publish(subject, message)
func (c *natsClient) Decode(msg *nats.Msg, v interface{}) error {
return c.conn.Enc.Decode(msg.Subject, msg.Data, v)