// Echo the data received on the WebSocket.
func NewWebSocketHandler(fn func([]byte) []byte) http.Handler {
var server websocket.Server
server.Handler = func(ws *websocket.Conn) {
log.Printf("--- Received connection")
buffer := make([]byte, 8000)
var err error
for {
var nBytes int
nBytes, err = ws.Read(buffer)
if err != nil {
break
}
frame := buffer[:nBytes]
if response := fn(frame); response != nil {
ws.Write(response)
}
}
log.Printf("--- End connection (%v)", err)
}
return server
}
func (h *Hrotti) AddListener(name string, config *ListenerConfig) error {
listener := &internalListener{name: name, url: *config.URL}
listener.stop = make(chan struct{})
h.listeners[name] = listener
ln, err := net.Listen("tcp", listener.url.Host)
if err != nil {
ERROR.Println(err.Error())
return err
}
if listener.url.Scheme == "ws" && len(listener.url.Path) == 0 {
listener.url.Path = "/"
}
h.listenersWaitGroup.Add(1)
INFO.Println("Starting MQTT listener on", listener.url.String())
go func() {
<-listener.stop
INFO.Println("Listener", name, "is stopping...")
ln.Close()
}()
//if this is a WebSocket listener
if listener.url.Scheme == "ws" {
var server websocket.Server
//override the Websocket handshake to accept any protocol name
server.Handshake = func(c *websocket.Config, req *http.Request) error {
c.Origin, _ = url.Parse(req.RemoteAddr)
c.Protocol = []string{"mqtt"}
return nil
}
//set up the ws connection handler, ie what we do when we get a new websocket connection
server.Handler = func(ws *websocket.Conn) {
ws.PayloadType = websocket.BinaryFrame
INFO.Println("New incoming websocket connection", ws.RemoteAddr())
listener.connections = append(listener.connections, ws)
h.InitClient(ws)
}
//set the path that the http server will recognise as related to this websocket
//server, needs to be configurable really.
http.Handle(listener.url.Path, server)
//ListenAndServe loops forever receiving connections and initiating the handler
//for each one.
go func(ln net.Listener) {
defer h.listenersWaitGroup.Done()
err := http.Serve(ln, nil)
if err != nil {
ERROR.Println(err.Error())
return
}
}(ln)
} else {
//loop forever accepting connections and launch InitClient as a goroutine with the connection
go func() {
defer h.listenersWaitGroup.Done()
for {
conn, err := ln.Accept()
if err != nil {
ERROR.Println(err.Error())
return
}
INFO.Println("New incoming connection", conn.RemoteAddr())
listener.connections = append(listener.connections, conn)
go h.InitClient(conn)
}
}()
}
return nil
}