// Publish sends a single MQTT PUBLISH message to the server. On completion, the
// supplied OnCompleteFunc is called. For QOS 0 messages, onComplete is called
// immediately after the message is sent to the outgoing buffer. For QOS 1 messages,
// onComplete is called when PUBACK is received. For QOS 2 messages, onComplete is
// called after the PUBCOMP message is received.
func (this *Server) Publish(msg *message.PublishMessage, onComplete OnCompleteFunc) error {
if err := this.checkConfiguration(); err != nil {
return err
}
if msg.Retain() {
if err := this.topicsMgr.Retain(msg); err != nil {
glog.Errorf("Error retaining message: %v", err)
}
}
if err := this.topicsMgr.Subscribers(msg.Topic(), msg.QoS(), &this.subs, &this.qoss); err != nil {
return err
}
msg.SetRetain(false)
//glog.Debugf("(server) Publishing to topic %q and %d subscribers", string(msg.Topic()), len(this.subs))
for _, s := range this.subs {
if s != nil {
fn, ok := s.(*OnPublishFunc)
if !ok {
glog.Errorf("Invalid onPublish Function")
} else {
(*fn)(msg)
}
}
}
return nil
}
// onPublish() is called when the server receives a PUBLISH message AND have completed
// the ack cycle. This method will get the list of subscribers based on the publish
// topic, and publishes the message to the list of subscribers.
func (this *service) onPublish(msg *message.PublishMessage) error {
if msg.Retain() {
if err := this.topicsMgr.Retain(msg); err != nil {
glog.Errorf("(%s) Error retaining message: %v", this.cid(), err)
}
}
err := this.topicsMgr.Subscribers(msg.Topic(), msg.QoS(), &this.subs, &this.qoss)
if err != nil {
glog.Errorf("(%s) Error retrieving subscribers list: %v", this.cid(), err)
return err
}
msg.SetRetain(false)
//glog.Debugf("(%s) Publishing to topic %q and %d subscribers", this.cid(), string(msg.Topic()), len(this.subs))
for _, s := range this.subs {
if s != nil {
fn, ok := s.(*OnPublishFunc)
if !ok {
glog.Errorf("Invalid onPublish Function")
return fmt.Errorf("Invalid onPublish Function")
} else {
(*fn)(msg)
}
}
}
return nil
}
// For PUBLISH message, we should figure out what QoS it is and process accordingly
// If QoS == 0, we should just take the next step, no ack required
// If QoS == 1, we should send back PUBACK, then take the next step
// If QoS == 2, we need to put it in the ack queue, send back PUBREC
func (this *service) processPublish(msg *message.PublishMessage) error {
switch msg.QoS() {
case message.QosExactlyOnce:
this.sess.Pub2in.Wait(msg, nil)
resp := message.NewPubrecMessage()
resp.SetPacketId(msg.PacketId())
_, err := this.writeMessage(resp)
return err
case message.QosAtLeastOnce:
resp := message.NewPubackMessage()
resp.SetPacketId(msg.PacketId())
if _, err := this.writeMessage(resp); err != nil {
return err
}
return this.onPublish(msg)
case message.QosAtMostOnce:
return this.onPublish(msg)
}
return fmt.Errorf("(%s) invalid message QoS %d.", this.cid(), msg.QoS())
}
func (this *rnode) rinsert(topic []byte, msg *message.PublishMessage) error {
// If there's no more topic levels, that means we are at the matching rnode.
if len(topic) == 0 {
l := msg.Len()
// Let's reuse the buffer if there's enough space
if l > cap(this.buf) {
this.buf = make([]byte, l)
} else {
this.buf = this.buf[0:l]
}
if _, err := msg.Encode(this.buf); err != nil {
return err
}
// Reuse the message if possible
if this.msg == nil {
this.msg = message.NewPublishMessage()
}
if _, err := this.msg.Decode(this.buf); err != nil {
return err
}
return nil
}
// Not the last level, so let's find or create the next level snode, and
// recursively call it's insert().
// ntl = next topic level
ntl, rem, err := nextTopicLevel(topic)
if err != nil {
return err
}
level := string(ntl)
// Add snode if it doesn't already exist
n, ok := this.rnodes[level]
if !ok {
n = newRNode()
this.rnodes[level] = n
}
return n.rinsert(rem, msg)
}
func (this *Session) RetainMessage(msg *message.PublishMessage) error {
this.mu.Lock()
defer this.mu.Unlock()
this.rbuf = make([]byte, msg.Len())
this.Retained = message.NewPublishMessage()
if _, err := msg.Encode(this.rbuf); err != nil {
return err
}
if _, err := this.Retained.Decode(this.rbuf); err != nil {
return err
}
return nil
}
func (this *service) publish(msg *message.PublishMessage, onComplete OnCompleteFunc) error {
//glog.Debugf("service/publish: Publishing %s", msg)
_, err := this.writeMessage(msg)
if err != nil {
return fmt.Errorf("(%s) Error sending %s message: %v", this.cid(), msg.Name(), err)
}
switch msg.QoS() {
case message.QosAtMostOnce:
if onComplete != nil {
return onComplete(msg, nil, nil)
}
return nil
case message.QosAtLeastOnce:
return this.sess.Pub1ack.Wait(msg, onComplete)
case message.QosExactlyOnce:
return this.sess.Pub2out.Wait(msg, onComplete)
}
return nil
}
func (this *memTopics) Retain(msg *message.PublishMessage) error {
this.rmu.Lock()
defer this.rmu.Unlock()
// So apparently, at least according to the MQTT Conformance/Interoperability
// Testing, that a payload of 0 means delete the retain message.
// https://eclipse.org/paho/clients/testing/
if len(msg.Payload()) == 0 {
return this.rroot.rremove(msg.Topic())
}
return this.rroot.rinsert(msg.Topic(), msg)
}