func (c *Client) Subscribe(topic string, qos byte, callback MessageHandler) Token {
token := newToken(Message.Subscribe).(*SubscribeToken)
if !c.IsConnected() {
token.err = errors.New("Not Connected.")
token.flowComplete()
return token
}
sub := Message.NewControlPacket(Message.Subscribe).(*Message.SubscribePacket)
if err := validateTopicAndQos(topic, qos); err != nil {
token.err = err
token.flowComplete()
return token
}
sub.Topics = append(sub.Topics, topic)
sub.Qoss = append(sub.Qoss, qos)
if sub.Qos != 0 {
sub.MessageID = c.getID(token)
}
if callback != nil {
c.MessageRouter.addRoute(topic, callback)
}
c.WriteChan <- &PacketAndToken{p: sub, t: token}
return token
}
// to publish message , we need topic to publish to ,
//QoS for this message , Is this message to be Retained OR not and message body.
func (c *Client) Publish(topic string, qos byte, retained bool, payload interface{}) Token {
token := newToken(Message.Publish).(*PublishToken)
if !c.IsConnected() {
token.err = errors.New("Not Connected.")
token.flowComplete()
return token
}
pub := Message.NewControlPacket(Message.Publish).(*Message.PublishPacket)
pub.Qos = qos
pub.TopicName = topic
pub.Retain = retained
pub.Dup = false
if pub.Qos != 0 {
pub.MessageID = c.getID(token)
}
//check for the type of payload.
switch payload.(type) {
case string:
pub.Payload = []byte(payload.(string))
case []byte:
pub.Payload = payload.([]byte)
default:
token.err = errors.New("Unknown payload type")
token.flowComplete()
return token
}
c.WriteChan <- &PacketAndToken{p: pub, t: token}
return token
}
func keepalive(c *Client) {
c.Workers.Add(1) // adding as worker.
defer c.Workers.Done() // i am done client. you can do whatever you want.
for {
select {
case <-c.stop:
return
default:
last := uint(time.Since(c.HeartBeat.get()).Seconds())
if last > uint(c.KeepAlive.Seconds()) {
token := newToken(Message.Pingreq)
ping := Message.NewControlPacket(Message.Pingreq).(*Message.PingreqPacket)
c.WriteChan <- &PacketAndToken{p: ping, t: token}
token.Wait()
}
time.Sleep(1 * time.Second)
}
}
}
func (c *Client) Disconnect() {
token := newToken(Message.Disconnect).(*DisconnectToken)
if !c.IsConnected() {
log.Println("Already Disconnected.")
}
disPacket := Message.NewControlPacket(Message.Disconnect).(*Message.DisconnectPacket)
c.WriteChan <- &PacketAndToken{p: disPacket, t: token}
token.Wait()
c.setConnected(false)
close(c.stop) // this will signal all the go routines to finish what they are doing.
c.disconnect()
}
func (c *Client) UnSubscribe(topics ...string) Token {
token := newToken(Message.Unsubscribe).(*UnsubscribeToken)
if !c.IsConnected() {
token.err = errors.New("Not Connected.")
token.flowComplete()
return token
}
unsub := Message.NewControlPacket(Message.Unsubscribe).(*Message.UnsubscribePacket)
unsub.Topics = make([]string, len(topics))
if unsub.Qos != 0 {
unsub.MessageID = c.getID(token)
}
copy(unsub.Topics, topics)
c.WriteChan <- &PacketAndToken{p: unsub, t: token}
for _, topic := range topics {
c.MessageRouter.deleteRoute(topic)
}
return token
}
func (c *Client) Connect() error {
conn, err := net.DialTimeout(c.Broker.Type, string(c.Broker.Addr+":"+strconv.Itoa(c.Broker.Port)), c.Broker.TimeOut)
if err != nil {
log.Println("Error while TCP connection.")
log.Println(err)
return err
}
c.Con = conn
//creating connect message : start.
m := (Message.NewControlPacket(Message.Connect)).(*Message.ConnectPacket)
m.ProtocolName = c.ProtocolName
m.ProtocolVersion = byte(c.ProtocolVersion)
m.ClientIdentifier = c.Id.(string)
m.CleanSession = c.CleanSession
m.WillFlag = c.WillFlag
m.WillRetain = c.WillRetain
if c.WillFlag {
m.WillQos = c.WillQos
m.WillTopic = c.WillTopic
m.WillMessage = c.WillPayload
}
if c.UserName != "" {
m.UsernameFlag = true
m.Username = c.UserName
//mustn't have password without user as well
if c.Password != "" {
m.PasswordFlag = true
m.Password = []byte(c.Password)
}
}
m.KeepaliveTimer = uint16(c.KeepAlive.Seconds())
// end.
if err != m.Write(c.Con) {
log.Println("Error while writing connect package.")
log.Println(err)
}
//This is the response packet came from server.
ca, err := Message.ReadPacket(c.Con) //read packet will validate packet and type.
if err != nil {
log.Println("Error in receiving.")
log.Println(err.Error())
return err
}
if ca == nil {
return errors.New("Received Nil Packet")
}
msg, ok := ca.(*Message.ConnackPacket)
if !ok {
return errors.New("Received wrong packet.")
}
if msg.ReturnCode != Message.Accepted {
c.Con.Close()
c.Con = nil
return errors.New("Wrong Response code.")
}
log.Println("Connected...!")
//connect is done.
// INIT SETUP : START.
c.WriteChan = make(chan *PacketAndToken, 100)
c.ReadChan = make(chan *Message.ControlPacket, 100)
c.InComingPubChan = make(chan *Message.PublishPacket, 100)
c.stop = make(chan struct{})
c.setConnected(true)
c.HeartBeat.update() // for keep alive.
c.MessageRouter.matchAndDispatch(c.InComingPubChan, c.Order, c)
//start contractors.
go writeContractor(c)
go readContractor(c)
if c.KeepAlive > 0 { // if 0 then alive forever. else we need to do some work.
go keepalive(c)
}
//INIT SETUP : DONE
return nil
}
func readContractor(c *Client) {
c.Workers.Add(1) // tell client that i am working in your group.
defer c.Workers.Done() // singnal client that i am done.
var err error
var msg Message.ControlPacket
log.Println("Reader Ready..!")
for {
select {
case <-c.stop:
return
default:
if msg, err = Message.ReadPacket(c.Con); err != nil {
log.Println("Error in read packet.")
log.Fatalln(err.Error())
return
}
switch msg.(type) {
case *Message.PingrespPacket:
log.Println("Received PingResp")
case *Message.SubackPacket:
log.Println("Received SUBACKS")
sa := msg.(*Message.SubackPacket)
token := c.getToken(sa.MessageID).(*SubscribeToken)
//these are the granted Qos From server.
// for i, qos := range sa.GrantedQoss {
// token.subResult[token.subs[i]] = qos
// }
token.flowComplete() // finish
c.freeID(sa.MessageID) // free ID.
case *Message.UnsubackPacket:
ua := msg.(*Message.UnsubackPacket)
token := c.getToken(ua.MessageID).(*UnsubscribeToken)
token.flowComplete()
c.freeID(ua.MessageID)
case *Message.PublishPacket: // calls when server publish to this client.
pp := msg.(*Message.PublishPacket)
switch pp.Qos {
case 2:
c.InComingPubChan <- pp
pr := Message.NewControlPacket(Message.Pubrec).(*Message.PubrecPacket)
pr.MessageID = pp.MessageID
c.WriteChan <- &PacketAndToken{p: pr, t: nil}
case 1:
c.InComingPubChan <- pp
pa := Message.NewControlPacket(Message.Puback).(*Message.PubackPacket)
pa.MessageID = pp.MessageID
c.WriteChan <- &PacketAndToken{p: pa, t: nil}
case 0:
c.InComingPubChan <- pp
}
case *Message.PubackPacket:
pa := msg.(*Message.PubackPacket)
c.getToken(pa.MessageID).flowComplete()
c.freeID(pa.MessageID)
case *Message.PubrecPacket:
prec := msg.(*Message.PubrecPacket)
//log.Println("Received PUBREC")
prel := Message.NewControlPacket(Message.Pubrel).(*Message.PubrelPacket)
prel.MessageID = prec.MessageID
select {
case c.WriteChan <- &PacketAndToken{p: prel, t: nil}:
case <-time.After(time.Second):
}
case *Message.PubrelPacket:
pr := msg.(*Message.PubrelPacket)
pc := Message.NewControlPacket(Message.Pubcomp).(*Message.PubcompPacket)
pc.MessageID = pr.MessageID
select {
case c.WriteChan <- &PacketAndToken{p: pc, t: nil}:
case <-time.After(time.Second):
}
case *Message.PubcompPacket:
//log.Println("Received PUBCOMP")
pc := msg.(*Message.PubcompPacket)
c.getToken(pc.MessageID).flowComplete()
c.freeID(pc.MessageID)
}
}
}
}