Sample application of gorilla/websocket and labstack/echo

app.js

$(function(){

  connect = function() {
    ws = new WebSocket("ws://" + window.location.host + "/ws");

    ws.onopen = function(e) {
      console.log("onopen", arguments);
    };

    ws.onclose = function(e) {
      console.log("onclose", arguments);
    };

    ws.onmessage = function(e) {
      console.log("onmessage", arguments);
    };
  }

  connect();

}); // end of document ready

main.go

package main

import (
	"log"
	"net/http"

	"github.com/gorilla/websocket"
	"github.com/labstack/echo"
	mw "github.com/labstack/echo/middleware"
)

type Message struct {
	Type string      `json:"type"`
	Data interface{} `json:"data"`
}

var upgrader = websocket.Upgrader{
	ReadBufferSize:  1024,
	WriteBufferSize: 1024,
}

func WsHandler(res http.ResponseWriter, req *http.Request) {
	conn, err := upgrader.Upgrade(res, req, nil)
	if err != nil {
		log.Println(err)
		return
	}

	err = conn.WriteJSON(Message{Type: "welcome", Data: "Welcome to websockets"})

	if err != nil {
		log.Println(err)
		return
	}
}

func main() {
	e := echo.New()

	e.Use(mw.Logger())
	e.Use(mw.Recover())

	e.Static("/js", "public/js")
	e.Static("/css", "public/css")
	e.Static("/font", "public/font")

	e.Index("public/index.html")

	e.Get("/ws", WsHandler)

	e.Run(":3000")
}