一、简介
websocket是个二进制协议，需要先通过Http协议进行握手，从而协商完成从Http协议向websocket协议的转换。一旦握手结束，当前的TCP连接后续将采用二进制websocket协议进行双向双工交互，自此与Http协议无关。
二、websocket demo
ws.go
package main
import (
"fmt"
"github.com/gorilla/websocket"
"net/http"
"time"
)
type wsMessage struct {
mType int
data []byte
}
type wsConnection struct {
wsSocket *websocket.Conn // 底层websocket
inChan chan *wsMessage // 读队列
outChan chan *wsMessage // 写队列
state int // 连接状态
}
func (wsCon *wsConnection) wsReadLoop() {
for {
if wsCon.state == 1 {
return
}
mType, data, err := wsCon.wsSocket.ReadMessage() // 阻塞
if err != nil {
fmt.Println("read err: %v", err)
continue
}
msg := &wsMessage{
mType,
data,
}
wsCon.inChan <- msg
}
}
func (wsCon *wsConnection) wsWriteLoop() {
for {
if wsCon.state == 1 {
return
}
msg := <-wsCon.outChan // 阻塞
err := wsCon.wsSocket.WriteMessage(msg.mType, msg.data)
if err != nil {
fmt.Printf("write err: %v", err)
continue
}
}
}
func (wsCon *wsConnection) bizLoop() {
for {
if wsCon.state == 1 {
return
}
// 处理消息
msg := <-wsCon.inChan
fmt.Println("process msg", string(msg.data))
// 返回响应
wsCon.outChan <- &wsMessage{
mType: 2,
data: []byte(fmt.Sprintf("%s done", string(msg.data))),
}
}
}
func (wsCon *wsConnection) healthLoop() {
defer wsCon.wsSocket.Close()
for {
time.Sleep(3 * time.Second)
// 返回响应
if err := wsCon.wsSocket.WriteMessage(2,
[]byte("心跳检查")); err != nil {
fmt.Println("write err: %v", err)
wsCon.state = 1
return
}
}
}
func wsHandler(resp http.ResponseWriter, req *http.Request) {
// 升级websocket协议
wsSocket, err := websocket.Upgrade(resp, req, nil, 1024, 1024)
if err != nil {
fmt.Println("upgrade err: %v", err)
}
// 一个请求，一个websocket 连接
wsCon := &wsConnection{
wsSocket: wsSocket,
inChan: make(chan *wsMessage, 1000),
outChan: make(chan *wsMessage, 1000),
}
go wsCon.wsReadLoop()
go wsCon.wsWriteLoop()
go wsCon.healthLoop()
go wsCon.bizLoop()
}
func main() {
http.HandleFunc("/ws", wsHandler)
http.ListenAndServe(":8080", nil)
}
ws.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:8080/ws");
ws.onopen = function (evt) {
print("OPEN");
}
ws.onclose = function (evt) {
print("CLOSE");
ws = null;
}
ws.onmessage = function (evt) {
const reader = new FileReader()
reader.onload = function (event) {
print("RESPONSE: " + event.target.result)
}
reader.readAsText(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!">
<button id="send">Send</button>
</form>
</td>
<td valign="top" width="50%">
<div id="output"></div>
</td>
</tr>
</table>
</body>
</html>实现效果
