func ExampleEncoder() {
enc := eventsource.NewEncoder(os.Stdout)
events := []eventsource.Event{
{ID: "1", Data: []byte("data")},
{ResetID: true, Data: []byte("id reset")},
{Type: "add", Data: []byte("1")},
}
for _, event := range events {
if err := enc.Encode(event); err != nil {
log.Fatal(err)
}
}
if err := enc.WriteField("", []byte("heartbeat")); err != nil {
log.Fatal(err)
}
if err := enc.Flush(); err != nil {
log.Fatal(err)
}
// Output:
// id: 1
// data: data
//
// id
// data: id reset
//
// event: add
// data: 1
//
// : heartbeat
//
}
func main() {
kingpin.MustParse(app.Parse(os.Args[1:]))
templateData, err := rice.MustFindBox("static").String("index.html")
if err != nil {
panic(err)
}
indexTemplate := template.Must(template.New("index").Parse(templateData))
latestImage := make([]imageUpdate, len(*videoDevices))
watchers := make(map[chan imageUpdate]bool)
for id, videoDevice := range *videoDevices {
thisDirectory := path.Join(*imageDirectory, fmt.Sprintf("cam%d", id))
if err := os.Mkdir(thisDirectory, 0755); err != nil && !os.IsExist(err) {
panic(err)
}
go func(id int, videoDevice, thisDirectory string) {
for {
logrus.WithFields(logrus.Fields{
"id": id,
"device": videoDevice,
"directory": thisDirectory,
}).Info("opening webcam")
err := exec.Command(
"streamer",
"-c", videoDevice,
"-t", "60",
"-r", "1",
"-o", path.Join(thisDirectory, fmt.Sprintf("snap_%d_00.jpeg", time.Now().Unix())),
).Run()
if err != nil {
logrus.WithFields(logrus.Fields{
"id": id,
"device": videoDevice,
"directory": thisDirectory,
"error": err.Error(),
}).Info("streamer crashed")
}
time.Sleep(time.Second * 5)
}
}(id, videoDevice, thisDirectory)
go func(id int) {
w, err := fsnotify.NewWatcher()
if err != nil {
panic(err)
}
if err := w.Watch(thisDirectory); err != nil {
panic(err)
}
for ev := range w.Event {
if ev.IsCreate() {
latestImage[id] = imageUpdate{
ID: id,
File: ev.Name,
Time: time.Now(),
}
for c := range watchers {
c <- latestImage[id]
}
}
}
}(id)
}
m := mux.NewRouter()
m.Path("/").Methods("GET").HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
w.Header().Set("content-type", "text/html")
w.WriteHeader(http.StatusOK)
if err := indexTemplate.Execute(w, struct{ Cameras []imageUpdate }{latestImage}); err != nil {
panic(err)
}
})
m.Path("/reset").Methods("POST").HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
if err := exec.Command("killall", "streamer").Run(); err != nil {
panic(err)
}
var m multierror.MultiError
var wg sync.WaitGroup
for _, d := range *usbDevices {
wg.Add(1)
go func(d string) {
defer wg.Done()
if err := exec.Command("usbreset", d).Run(); err != nil {
m = append(m, err)
}
}(d)
}
wg.Wait()
if m != nil {
panic(m)
}
})
m.Path("/latest/{id:[0-9]+}.jpeg").Methods("GET").HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
vars := mux.Vars(r)
var id int
if idInt64, err := strconv.ParseInt(vars["id"], 10, 8); err != nil {
panic(err)
} else {
id = int(idInt64)
}
if id >= len(*videoDevices) {
http.Error(w, "not found", http.StatusNotFound)
return
}
f, err := os.Open(latestImage[id].File)
if err != nil {
panic(err)
}
w.Header().Set("content-type", "image/jpeg")
if _, err := io.Copy(w, f); err != nil {
panic(err)
}
})
m.Path("/stream").Methods("GET").HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
enc := eventsource.NewEncoder(w)
w.Header().Set("content-type", "text/event-stream")
w.WriteHeader(http.StatusOK)
c := make(chan imageUpdate, 10)
watchers[c] = true
defer delete(watchers, c)
cn := w.(http.CloseNotifier).CloseNotify()
for {
select {
case e, ok := <-c:
if !ok {
break
}
f, err := os.Open(e.File)
if err != nil {
panic(err)
}
d, err := ioutil.ReadAll(f)
if err != nil {
panic(err)
}
ev := eventsource.Event{
Type: "image",
Data: []byte(fmt.Sprintf(
"%d::%s::%s",
e.ID,
e.Time.String(),
base64.StdEncoding.EncodeToString(d),
)),
}
if err := enc.Encode(ev); err != nil {
panic(err)
}
if err := enc.Flush(); err != nil {
panic(err)
}
case <-cn:
return
case <-time.After(time.Second * 30):
if err := enc.WriteField("heartbeat", nil); err != nil {
panic(err)
}
}
}
})
n := negroni.New()
n.Use(negroni.NewRecovery())
n.Use(negronilogrus.NewMiddleware())
n.UseHandler(m)
if err := http.ListenAndServe(*addr, n); err != nil {
panic(err)
}
}