func (this *Server) getSession(svc *service, req *message.ConnectMessage, resp *message.ConnackMessage) error {
// If CleanSession is set to 0, the server MUST resume communications with the
// client based on state from the current session, as identified by the client
// identifier. If there is no session associated with the client identifier the
// server must create a new session.
//
// If CleanSession is set to 1, the client and server must discard any previous
// session and start a new one. This session lasts as long as the network c
// onnection. State data associated with this session must not be reused in any
// subsequent session.
var err error
// Check to see if the client supplied an ID, if not, generate one and set
// clean session.
if len(req.ClientId()) == 0 {
req.SetClientId([]byte(fmt.Sprintf("internalclient%d", svc.id)))
req.SetCleanSession(true)
}
cid := string(req.ClientId())
// If CleanSession is NOT set, check the session store for existing session.
// If found, return it.
if !req.CleanSession() {
if svc.sess, err = this.sessMgr.Get(cid); err == nil {
resp.SetSessionPresent(true)
if err := svc.sess.Update(req); err != nil {
return err
}
}
}
// If CleanSession, or no existing session found, then create a new one
if svc.sess == nil {
if svc.sess, err = this.sessMgr.New(cid); err != nil {
return err
}
resp.SetSessionPresent(false)
if err := svc.sess.Init(req); err != nil {
return err
}
}
return nil
}
func (this *Session) Update(msg *message.ConnectMessage) error {
this.mu.Lock()
defer this.mu.Unlock()
this.cbuf = make([]byte, msg.Len())
this.Cmsg = message.NewConnectMessage()
if _, err := msg.Encode(this.cbuf); err != nil {
return err
}
if _, err := this.Cmsg.Decode(this.cbuf); err != nil {
return err
}
return nil
}
func (this *Session) Init(msg *message.ConnectMessage) error {
this.mu.Lock()
defer this.mu.Unlock()
if this.initted {
return fmt.Errorf("Session already initialized")
}
this.cbuf = make([]byte, msg.Len())
this.Cmsg = message.NewConnectMessage()
if _, err := msg.Encode(this.cbuf); err != nil {
return err
}
if _, err := this.Cmsg.Decode(this.cbuf); err != nil {
return err
}
if this.Cmsg.WillFlag() {
this.Will = message.NewPublishMessage()
this.Will.SetQoS(this.Cmsg.WillQos())
this.Will.SetTopic(this.Cmsg.WillTopic())
this.Will.SetPayload(this.Cmsg.WillMessage())
this.Will.SetRetain(this.Cmsg.WillRetain())
}
this.topics = make(map[string]byte, 1)
this.id = string(msg.ClientId())
this.Pub1ack = newAckqueue(defaultQueueSize)
this.Pub2in = newAckqueue(defaultQueueSize)
this.Pub2out = newAckqueue(defaultQueueSize)
this.Suback = newAckqueue(defaultQueueSize)
this.Unsuback = newAckqueue(defaultQueueSize)
this.Pingack = newAckqueue(defaultQueueSize)
this.initted = true
return nil
}
// Connect is for MQTT clients to open a connection to a remote server. It needs to
// know the URI, e.g., "tcp://127.0.0.1:1883", so it knows where to connect to. It also
// needs to be supplied with the MQTT CONNECT message.
func (this *Client) Connect(uri string, msg *message.ConnectMessage) (err error) {
this.checkConfiguration()
if msg == nil {
return fmt.Errorf("msg is nil")
}
u, err := url.Parse(uri)
if err != nil {
return err
}
if u.Scheme != "tcp" {
return ErrInvalidConnectionType
}
conn, err := net.Dial(u.Scheme, u.Host)
if err != nil {
return err
}
defer func() {
if err != nil {
conn.Close()
}
}()
if msg.KeepAlive() < minKeepAlive {
msg.SetKeepAlive(minKeepAlive)
}
if err = writeMessage(conn, msg); err != nil {
return err
}
conn.SetReadDeadline(time.Now().Add(time.Second * time.Duration(this.ConnectTimeout)))
resp, err := getConnackMessage(conn)
if err != nil {
return err
}
if resp.ReturnCode() != message.ConnectionAccepted {
return resp.ReturnCode()
}
this.svc = &service{
id: atomic.AddUint64(&gsvcid, 1),
client: true,
conn: conn,
keepAlive: int(msg.KeepAlive()),
connectTimeout: this.ConnectTimeout,
ackTimeout: this.AckTimeout,
timeoutRetries: this.TimeoutRetries,
}
err = this.getSession(this.svc, msg, resp)
if err != nil {
return err
}
p := topics.NewMemProvider()
topics.Register(this.svc.sess.ID(), p)
this.svc.topicsMgr, err = topics.NewManager(this.svc.sess.ID())
if err != nil {
return err
}
if err := this.svc.start(); err != nil {
this.svc.stop()
return err
}
this.svc.inStat.increment(int64(msg.Len()))
this.svc.outStat.increment(int64(resp.Len()))
return nil
}