Method validateTopicName

server/session.go:565–605

validateTopicName expands session specific topic name to global name Returns topic: session-specific topic name the message recepient should see routeTo: routable global topic name err: *ServerComMessage with an error to return to the sender

(msgId, topic string, timestamp time.Time)

//   routeTo: routable global topic name
//   err: *ServerComMessage with an error to return to the sender
func (s *Session) validateTopicName(msgId, topic string, timestamp time.Time) (string, string, *ServerComMessage) {

	if topic == "" {
		return "", "", ErrMalformed(msgId, "", timestamp)
	}

	if !strings.HasPrefix(topic, "grp") && s.uid.IsZero() {
		// me and p2p topics require authentication
		return "", "", ErrAuthRequired(msgId, topic, timestamp)
	}

	// Topic to route to i.e. rcptto: or s.subs[routeTo]
	routeTo := topic

	if topic == "me" {
		routeTo = s.uid.UserId()
	} else if strings.HasPrefix(topic, "usr") {
		// packet to a specific user
		uid2 := types.ParseUserId(topic)
		if uid2.IsZero() {
			// Ensure the user id is valid
			return "", "", ErrMalformed(msgId, topic, timestamp)
		} else if uid2 == s.uid {
			// Use 'me' to access self-topic
			return "", "", ErrPermissionDenied(msgId, topic, timestamp)
		}
		routeTo = s.uid.P2PName(uid2)
		topic = s.uid.UserId() // but the echo message should come back as uid2.Name()
	} else if strings.HasPrefix(topic, "p2p") {
		uid1, uid2, err := types.ParseP2P(topic)
		if err != nil || uid1.IsZero() || uid2.IsZero() || uid1 == uid2 {
			// Ensure the user ids are valid
			return "", "", ErrMalformed(msgId, topic, timestamp)
		} else if uid1 != s.uid && uid2 != s.uid {
			// One can't access someone else's p2p topic
			return "", "", ErrPermissionDenied(msgId, topic, timestamp)
		}
	}

	return topic, routeTo, nil
}