Method subscriptionReply

server/topic.go:1376–1483

subscriptionReply generates a response to a subscription request

(asChan bool, msg *ClientComMessage)

// subscriptionReply generates a response to a subscription request
func (t *Topic) subscriptionReply(asChan bool, msg *ClientComMessage) error {
	// The topic is already initialized by the Hub

	msgsub := msg.Sub

	// For newly created topics report topic creation time.
	var now time.Time
	if msgsub.Created {
		now = t.updated
	} else {
		now = types.TimeNow()
	}

	asUid := types.ParseUserId(msg.AsUser)

	if !msgsub.Newsub && (t.cat == types.TopicCatP2P || t.cat == types.TopicCatGrp) {
		// Check if this is a new subscription (P2P & GRP only. SLF, SYS are excluded here).
		pud, found := t.perUser[asUid]
		msgsub.Newsub = !found || pud.deleted
	}

	var private any
	var mode string
	if msgsub.Set != nil {
		if msgsub.Set.Sub != nil {
			if msgsub.Set.Sub.User != "" {
				msg.sess.queueOut(ErrMalformedReply(msg, now))
				return errors.New("user id must not be specified")
			}
			mode = msgsub.Set.Sub.Mode
		}

		if msgsub.Set.Desc != nil {
			private = msgsub.Set.Desc.Private
		}
	}

	var err error
	var modeChanged *MsgAccessMode
	// Create new subscription or modify an existing one.
	if modeChanged, err = t.thisUserSub(msg.sess, msg, asUid, asChan, mode, private); err != nil {
		return err
	}

	hasJoined := true
	if modeChanged != nil {
		if acs, err := types.ParseAcs([]byte(modeChanged.Mode)); err == nil {
			hasJoined = acs.IsJoiner()
		}
	}

	if hasJoined {
		// Subscription successfully created. Link topic to session.
		msg.sess.addSub(t.name, &Subscription{
			broadcast: t.clientMsg,
			done:      t.unreg,
			meta:      t.meta,
			supd:      t.supd,