go 实现websocket推送

index.html

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <script>
        window.addEventListener("load", function(evt) {
            var output = document.getElementById("output");
            var input = document.getElementById("input");
            var ws;
            var print = function(message) {
                var d = document.createElement("div");
                d.innerHTML = message;
                output.appendChild(d);
            };
            document.getElementById("open").onclick = function(evt) {
                if (ws) {
                    return false;
                }
                ws = new WebSocket("ws://localhost:8888/ws");
                ws.onopen = function(evt) {
                    print("OPEN");
                }
                ws.onclose = function(evt) {
                    print("CLOSE");
                    ws = null;
                }
                ws.onmessage = function(evt) {
                    print("RESPONSE: " + evt.data);
                }
                ws.onerror = function(evt) {
                    print("ERROR: " + evt.data);
                }
                return false;
            };
            document.getElementById("send").onclick = function(evt) {
                if (!ws) {
                    return false;
                }
                print("SEND: " + input.value);
                ws.send(input.value);
                return false;
            };
            document.getElementById("close").onclick = function(evt) {
                if (!ws) {
                    return false;
                }
                ws.close();
                return false;
            };
        });
    </script>
</head>
<body>
<table>
    <tr><td valign="top" width="50%">
            <p>Click "Open" to create a connection to the server,
                "Send" to send a message to the server and "Close" to close the connection.
                You can change the message and send multiple times.
            </p>
            <form>
                <button id="open">Open</button>
                <button id="close">Close</button>
                <input id="input" type="text" value="Hello world!">
                <button id="send">Send</button>
            </form>
        </td><td valign="top" width="50%">
            <div id="output"></div>
        </td></tr></table>
</body>
</html>

server.go

package main

import (
	"fmt"
	"github.com/gorilla/websocket"
	"net/http"
)

var (
	upgrader = websocket.Upgrader{
		CheckOrigin:func(r *http.Request) bool{
			return true
		},
	}
)



func wsHandler(w http.ResponseWriter,r *http.Request)  {

	var (
		conn *websocket.Conn
		err error
		data []byte
	)
	if conn,err = upgrader.Upgrade(w,r,nil);err != nil{
		return
	}

	for{
		if _,data,err = conn.ReadMessage();err != nil{
			goto ERR
		}
		fmt.Println(data)
		if err = conn.WriteMessage(websocket.TextMessage,[]byte("服务器数据"));err !=nil{
			goto ERR
		}
	}
	ERR:
		conn.Close()

}

func main() {
	http.HandleFunc("/ws",wsHandler)
	http.ListenAndServe("0.0.0.0:8888",nil)
}

后台运行go即可开启websocket服务