SSEvents with golang

app.go

package main

import (
	"io"
	"strconv"
	"time"

	"github.com/gin-gonic/gin"
)

// Event for SSE
type Event struct {
	ID      int
	Message string
}

func sendEvents(listener chan interface{}) {
	i := 0
	ticker := time.NewTicker(1 * time.Second)
	for _ = range ticker.C {
		i++
		listener <- Event{i, "Hello " + strconv.Itoa(i)}
		if i >= 5 {
			ticker.Stop()
			close(listener)
		}
	}
}

func streamEvents(c *gin.Context) {
	listener := make(chan interface{})
	go sendEvents(listener)
	c.Stream(func(w io.Writer) bool {
		event := <-listener
		if event != nil {
			c.SSEvent("message", event)
			return true
		}
		return false
	})
}

func ping(c *gin.Context) {
	c.JSON(200, gin.H{
		"message": "pong",
	})
}

func main() {
	r := gin.Default()
	r.GET("/ping", ping)
	r.GET("/stream", streamEvents)
	r.Run() // listen and server on 0.0.0.0:8080
}

browser.js

var client = new EventSource("http://localhost:8080/stream/")
client.onmessage = function (msg) {
  console.log(msg)
}