I’m trying to push the time to the browser using channels, so I wrote the below:
package main
import (
"net/http"
"time"
)
type DataPasser struct {
logs chan string
}
func main() {
passer := &DataPasser{logs: make(chan string)}
go func() {
for {
passer.logs <- time.Now().String()
}
}()
http.HandleFunc("/", passer.handleHello)
http.ListenAndServe(":9999", nil)
}
func (p *DataPasser) handleHello(w http.ResponseWriter, r *http.Request) {
for {
w.Write([]byte(<-p.logs))
}
/* for {
io.WriteString(w, <-p.logs)
}
*/
}
It worked by kept adding new lines with each new time, as below:
What I need is to get single line, that is cleared and replaced with the new time every time the server sending time to it? any help?
UPDATE
I tried using SSE server sent event, as below but did not work:
package main
import (
"net/http"
"time"
)
type DataPasser struct {
logs chan string
}
func main() {
passer := &DataPasser{logs: make(chan string)}
t := time.NewTicker(time.Second)
defer t.Stop()
go func() {
for range t.C {
passer.logs <- time.Now().String()
}
}()
http.HandleFunc("/", passer.handleHello)
http.ListenAndServe(":9999", nil)
}
func (p *DataPasser) handleHello(w http.ResponseWriter, r *http.Request) {
setupCORS(&w, r)
w.Header().Set("Content-Type", "text/event-stream")
w.Header().Set("Cache-Control", "no-cache")
w.Header().Set("Connection", "keep-alive")
flusher, ok := w.(http.Flusher)
if !ok {
http.Error(w, "Internal error", 500)
return
}
for {
w.Write([]byte(<-p.logs))
// c := []byte(<-p.logs)
// fmt.Fprint(w, c)
flusher.Flush()
}
/* for {
io.WriteString(w, <-p.logs)
}
*/
// w.Write([]byte("Hi, from Service: " + ws.name))
}
func setupCORS(w *http.ResponseWriter, req *http.Request) {
(*w).Header().Set("Cache-Control", "no-cache")
(*w).Header().Set("Access-Control-Allow-Origin", "*")
(*w).Header().Set("Access-Control-Allow-Methods", "POST, GET, OPTIONS, PUT, DELETE")
(*w).Header().Set("Access-Control-Allow-Headers", "Accept, Content-Type, Content-Length, Accept-Encoding, X-CSRF-Token, Authorization")
}
And the html file as:
<html>
<head></head>
<body>
<div id="counter" width="500" height="600">
</body>
<script>
var source = new EventSource("http://localhost:9999/");
source.onmessage = function (event) {
console.log(event)
var counter = event.data; // JSON.parse(event.data);
document.getElementById("counter").innerHTML = counter;
}
</script>
</html>