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http.go
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/
http.go
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// Copyright © 2017 The Things Network
// Use of this source code is governed by the MIT license that can be found in the LICENSE file.
package dummy
import (
"encoding/json"
"net/http"
"sync"
"github.com/TheThingsNetwork/gateway-connector-bridge/types"
"github.com/apex/log"
"github.com/googollee/go-socket.io"
)
const (
room = "evts"
connectEvt = "gtw-connect"
disconnectEvt = "gtw-disconnect"
uplinkEvt = "uplink"
downlinkEvt = "downlink"
statusEvt = "status"
)
// Server is a http server that exposes some events over websockets
type Server struct {
ctx log.Interface
addr string
server *socketio.Server
connect chan string
disconnect chan string
uplink chan *types.UplinkMessage
downlink chan *types.DownlinkMessage
status chan *types.StatusMessage
mu sync.RWMutex // Protects connectedGateways
connectedGateways []string
}
// NewServer creates a new server
func NewServer(ctx log.Interface, addr string) (*Server, error) {
server, err := socketio.NewServer(nil)
if err != nil {
return nil, err
}
return &Server{
ctx: ctx.WithField("Connector", "Dummy-HTTP"),
server: server,
addr: addr,
connect: make(chan string, BufferSize),
disconnect: make(chan string, BufferSize),
uplink: make(chan *types.UplinkMessage, BufferSize),
downlink: make(chan *types.DownlinkMessage, BufferSize),
status: make(chan *types.StatusMessage, BufferSize),
connectedGateways: make([]string, 0),
}, nil
}
// Listen opens the server and starts listening for http requests
func (s *Server) Listen() {
s.server.On("connection", func(so socketio.Socket) {
s.handleConnect(so)
})
go s.handleEvents()
mux := http.NewServeMux()
mux.Handle("/socket.io/", s.server)
mux.Handle("/", http.FileServer(http.Dir("./assets")))
mux.HandleFunc("/gateways", func(res http.ResponseWriter, _ *http.Request) {
res.Header().Add("content-type", "application/json; charset=utf-8")
enc := json.NewEncoder(res)
enc.Encode(s.ConnectedGateways())
})
s.ctx.Infof("HTTP server listening on %s", s.addr)
err := http.ListenAndServe(s.addr, mux)
if err != nil {
s.ctx.WithError(err).Fatal("Could not serve HTTP")
}
}
func (s *Server) handleConnect(so socketio.Socket) {
ctx := s.ctx.WithField("ID", so.Id)
ctx.Debug("Socket connected")
so.Join(room)
so.On("disconnection", func() {
ctx.Debug("Socket disconnected")
})
}
func (s *Server) handleEvents() {
for {
select {
case gtwID := <-s.connect:
s.emit(connectEvt, gtwID)
case gtwID := <-s.disconnect:
s.emit(disconnectEvt, gtwID)
case msg := <-s.uplink:
s.emit(uplinkEvt, msg)
case msg := <-s.downlink:
s.emit(downlinkEvt, msg)
case msg := <-s.status:
s.emit(statusEvt, msg)
}
}
}
func (s *Server) emit(name string, v interface{}) {
marshalled, err := json.Marshal(v)
if err != nil {
s.ctx.WithError(err).Error("Could not marshal event")
return
}
s.server.BroadcastTo(room, name, string(marshalled))
}
// Uplink emits an uplink message on the server page
func (s *Server) Uplink(msg *types.UplinkMessage) {
select {
case s.uplink <- msg:
return
default:
s.ctx.Warn("Dropping uplink message on websocket")
}
}
// Downlink emits a downlink message on the server page
func (s *Server) Downlink(msg *types.DownlinkMessage) {
select {
case s.downlink <- msg:
return
default:
s.ctx.Warn("Dropping downlink message on websocket")
}
}
// Status emits a status message on the server page
func (s *Server) Status(msg *types.StatusMessage) {
select {
case s.status <- msg:
return
default:
s.ctx.Warn("Dropping status message on websocket")
}
}
// Connect emits a message when a gateway connects
func (s *Server) Connect(gatewayID string) {
select {
case s.connect <- gatewayID:
default:
s.ctx.Warn("Dropping connect message on websocket")
}
s.mu.Lock()
defer s.mu.Unlock()
for _, existing := range s.connectedGateways {
if existing == gatewayID {
return
}
}
s.connectedGateways = append(s.connectedGateways, gatewayID)
}
// Disconnect emits a message when a gateway disconnects
func (s *Server) Disconnect(gatewayID string) {
select {
case s.disconnect <- gatewayID:
default:
s.ctx.Warn("Dropping disconnect message on websocket")
}
s.mu.Lock()
defer s.mu.Unlock()
previouslyConnectedGateways := s.connectedGateways
s.connectedGateways = make([]string, 0, len(previouslyConnectedGateways))
for _, existing := range previouslyConnectedGateways {
if existing != gatewayID {
s.connectedGateways = append(s.connectedGateways, existing)
}
}
}
// ConnectedGateways returns the list of connected gateway IDs
func (s *Server) ConnectedGateways() []string {
s.mu.RLock()
defer s.mu.RUnlock()
return s.connectedGateways
}