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175 lines
4.8 KiB
175 lines
4.8 KiB
/** |
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* Standalone signaling server for the Nextcloud Spreed app. |
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* Copyright (C) 2017 struktur AG |
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* |
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* @author Joachim Bauch <bauch@struktur.de> |
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* |
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* @license GNU AGPL version 3 or any later version |
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* |
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* This program is free software: you can redistribute it and/or modify |
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* it under the terms of the GNU Affero General Public License as published by |
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* the Free Software Foundation, either version 3 of the License, or |
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* (at your option) any later version. |
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* |
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* This program is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU Affero General Public License for more details. |
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* |
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* You should have received a copy of the GNU Affero General Public License |
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* along with this program. If not, see <http://www.gnu.org/licenses/>. |
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*/ |
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package signaling |
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import ( |
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"encoding/base64" |
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"fmt" |
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"log" |
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"os" |
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"os/signal" |
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"time" |
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"github.com/nats-io/nats.go" |
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) |
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const ( |
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initialConnectInterval = time.Second |
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maxConnectInterval = 8 * time.Second |
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) |
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type NatsMessage struct { |
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SendTime time.Time `json:"sendtime"` |
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Type string `json:"type"` |
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Message *ServerMessage `json:"message,omitempty"` |
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Room *BackendServerRoomRequest `json:"room,omitempty"` |
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Permissions []Permission `json:"permissions,omitempty"` |
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Id string `json:"id"` |
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} |
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type NatsSubscription interface { |
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Unsubscribe() error |
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} |
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type NatsClient interface { |
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Close() |
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Subscribe(subject string, ch chan *nats.Msg) (NatsSubscription, error) |
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Publish(subject string, message interface{}) error |
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PublishNats(subject string, message *NatsMessage) error |
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PublishMessage(subject string, message *ServerMessage) error |
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PublishBackendServerRoomRequest(subject string, message *BackendServerRoomRequest) error |
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Decode(msg *nats.Msg, v interface{}) error |
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} |
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// The NATS client doesn't work if a subject contains spaces. As the room id |
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// can have an arbitrary format, we need to make sure the subject is valid. |
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// See "https://github.com/nats-io/nats.js/issues/158" for a similar report. |
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func GetEncodedSubject(prefix string, suffix string) string { |
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return prefix + "." + base64.StdEncoding.EncodeToString([]byte(suffix)) |
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} |
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type natsClient struct { |
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nc *nats.Conn |
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conn *nats.EncodedConn |
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} |
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func NewNatsClient(url string) (NatsClient, error) { |
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if url == ":loopback:" { |
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log.Println("No NATS url configured, using internal loopback client") |
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return NewLoopbackNatsClient() |
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} |
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client := &natsClient{} |
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var err error |
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client.nc, err = nats.Connect(url, |
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nats.ClosedHandler(client.onClosed), |
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nats.DisconnectHandler(client.onDisconnected), |
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nats.ReconnectHandler(client.onReconnected)) |
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interrupt := make(chan os.Signal, 1) |
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signal.Notify(interrupt, os.Interrupt) |
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defer signal.Stop(interrupt) |
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delay := initialConnectInterval |
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timer := time.NewTimer(delay) |
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// The initial connect must succeed, so we retry in the case of an error. |
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for err != nil { |
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log.Printf("Could not create connection (%s), will retry in %s", err, delay) |
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timer.Reset(delay) |
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select { |
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case <-interrupt: |
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return nil, fmt.Errorf("interrupted") |
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case <-timer.C: |
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// Retry connection |
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delay = delay * 2 |
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if delay > maxConnectInterval { |
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delay = maxConnectInterval |
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} |
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} |
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client.nc, err = nats.Connect(url) |
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} |
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log.Printf("Connection established to %s (%s)", client.nc.ConnectedUrl(), client.nc.ConnectedServerId()) |
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// All communication will be JSON based. |
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client.conn, _ = nats.NewEncodedConn(client.nc, nats.JSON_ENCODER) |
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return client, nil |
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} |
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func (c *natsClient) Close() { |
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c.conn.Close() |
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} |
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func (c *natsClient) onClosed(conn *nats.Conn) { |
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log.Println("NATS client closed", conn.LastError()) |
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} |
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func (c *natsClient) onDisconnected(conn *nats.Conn) { |
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log.Println("NATS client disconnected") |
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} |
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func (c *natsClient) onReconnected(conn *nats.Conn) { |
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log.Printf("NATS client reconnected to %s (%s)", conn.ConnectedUrl(), conn.ConnectedServerId()) |
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} |
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func (c *natsClient) Subscribe(subject string, ch chan *nats.Msg) (NatsSubscription, error) { |
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return c.nc.ChanSubscribe(subject, ch) |
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} |
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func (c *natsClient) Publish(subject string, message interface{}) error { |
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return c.conn.Publish(subject, message) |
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} |
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func (c *natsClient) PublishNats(subject string, message *NatsMessage) error { |
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return c.Publish(subject, message) |
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} |
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func (c *natsClient) PublishMessage(subject string, message *ServerMessage) error { |
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msg := &NatsMessage{ |
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SendTime: time.Now(), |
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Type: "message", |
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Message: message, |
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} |
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return c.PublishNats(subject, msg) |
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} |
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func (c *natsClient) PublishBackendServerRoomRequest(subject string, message *BackendServerRoomRequest) error { |
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msg := &NatsMessage{ |
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SendTime: time.Now(), |
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Type: "room", |
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Room: message, |
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} |
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return c.PublishNats(subject, msg) |
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} |
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func (c *natsClient) Decode(msg *nats.Msg, v interface{}) error { |
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return c.conn.Enc.Decode(msg.Subject, msg.Data, v) |
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}
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