Go语言中websocket的使用demo分享
服务端代码 main.go
package main
import (
"errors"
"fmt"
"net/http"
"sync"
"time"
"github.com/gorilla/websocket"
)
// http升级websocket协议的配置
var wsUpgrader = websocket.Upgrader{
// 允许所有CORS跨域请求
CheckOrigin: func(r *http.Request) bool {
return true
},
}
// 客户端读写消息
type wsMessage struct {
messageType int
data []byte
}
// 客户端连接
type wsConnection struct {
wsSocket *websocket.Conn // 底层websocket
inChan chan *wsMessage // 读队列
outChan chan *wsMessage // 写队列
mutex sync.Mutex // 避免重复关闭管道
isClosed bool
closeChan chan byte // 关闭通知
}
func (wsConn *wsConnection) wsReadLoop() {
for {
// 读一个message
msgType, data, err := wsConn.wsSocket.ReadMessage()
if err != nil {
goto error
}
req := &wsMessage{
msgType,
data,
}
// 放入请求队列
select {
case wsConn.inChan <- req:
case <-wsConn.closeChan:
goto closed
}
}
error:
wsConn.wsClose()
closed:
}
func (wsConn *wsConnection) wsWriteLoop() {
for {
select {
// 取一个应答
case msg := <-wsConn.outChan:
// 写给websocket
if err := wsConn.wsSocket.WriteMessage(msg.messageType, msg.data); err != nil {
goto error
}
case <-wsConn.closeChan:
goto closed
}
}
error:
wsConn.wsClose()
closed:
}
func (wsConn *wsConnection) procLoop() {
// 启动一个gouroutine发送心跳
go func() {
for { //不断向客户端写数据，其实没有它也是一样的，客户端可以检测到断开
time.Sleep(2 * time.Second)
if err := wsConn.wsWrite(websocket.TextMessage, []byte("heartbeat from server")); err != nil {
fmt.Println("heartbeat fail")
wsConn.wsClose()
break
}
}
}()
// 这是一个同步处理模型（只是一个例子），如果希望并行处理可以每个请求一个gorutine，注意控制并发goroutine的数量!!!
for {
msg, err := wsConn.wsRead()
if err != nil {
fmt.Println("read fail")
break
}
fmt.Println(string(msg.data))
err = wsConn.wsWrite(msg.messageType, msg.data) // 读到数据后，同步的去写数据。应该写成异步
if err != nil {
fmt.Println("write fail")
break
}
}
}
func wsHandler(resp http.ResponseWriter, req *http.Request) {
// 应答客户端告知升级连接为websocket
wsSocket, err := wsUpgrader.Upgrade(resp, req, nil)
if err != nil {
return
}
wsConn := &wsConnection{
wsSocket: wsSocket,
inChan: make(chan *wsMessage, 1000),
outChan: make(chan *wsMessage, 1000),
closeChan: make(chan byte),
isClosed: false,
}
// 处理器
go wsConn.procLoop()
// 读协程
go wsConn.wsReadLoop()
// 写协程
go wsConn.wsWriteLoop()
}
func (wsConn *wsConnection) wsWrite(messageType int, data []byte) error {
select {
case wsConn.outChan <- &wsMessage{messageType, data}:
case <-wsConn.closeChan:
return errors.New("websocket closed")
}
return nil
}
func (wsConn *wsConnection) wsRead() (*wsMessage, error) {
select {
case msg := <-wsConn.inChan:
return msg, nil
case <-wsConn.closeChan:
}
return nil, errors.New("websocket closed")
}
func (wsConn *wsConnection) wsClose() {
wsConn.wsSocket.Close()
wsConn.mutex.Lock()
defer wsConn.mutex.Unlock()
if !wsConn.isClosed {
wsConn.isClosed = true
close(wsConn.closeChan)
}
}
func main() {
http.HandleFunc("/ws", wsHandler)
http.ListenAndServe("0.0.0.0:7777", nil)
}前端代码 client.html
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<script>
window.addEventListener("load", function(evt) {
const output = document.getElementById("output");
const input = document.getElementById("input");
let ws;
const print = function(message) {
const 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:7777/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 >Open</button>
<button >Close</button>
<input type="text" value="Hello world!">
<button >Send</button>
</form>
</td><td valign="top" width="50%">
<div ></div>
</td></tr></table>
</body>
</html>原文地址：https://juejin.cn/post/7181779790611873852
