使用Go语言创建WebSocket服务的实现示例
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GET /chat HTTP/1.1 Host: server.example.com Upgrade: websocket Connection: Upgrade Sec-WebSocket-Key: x3JJHMbDL1EzLkh9GBhXDw== Sec-WebSocket-Protocol: chat, superchat Sec-WebSocket-Version: 13 Origin: http://example.com
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HTTP/1.1 101 Switching Protocols Upgrade: websocket Connection: Upgrade Sec-WebSocket-Accept: HSmrc0sMlYUkAGmm5OPpG2HaGWk= Sec-WebSocket-Protocol: chat
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é¦åï¼è®©æ们å建ä¸ä¸ªå¸¦æ WebSocket 端ç¹ç HTTP å¤çç¨åºï¼
// HTTP server with WebSocket endpoint
func Server() {
http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
ws, err := NewHandler(w, r)
if err != nil {
// handle error
}
if err = ws.Handshake(); err != nil {
// handle error
}
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åå§æ¡æ请æ±å§ç»æ¥èªå®¢æ·ç«¯ãæå¡å¨ç¡®å®äº WebSocket 请æ±åï¼éè¦ä½¿ç¨æ¡æååºè¿è¡åå¤ã
请记ä½ï¼ä½ æ æ³ä½¿ç¨ http.ResponseWriter ç¼åååºï¼å 为ä¸æ¦å¼å§åéååºï¼å®å°å³éå¶åºç¡ç TCP è¿æ¥ï¼è¿æ¯ HTTP åè®®çè¿è¡æºå¶å³å®çï¼åéååºåå³å³éè¿æ¥ï¼ã
å æ¤ï¼æ¨éè¦ä½¿ç¨ HTTP å«æ( hijack )ãéè¿å«æï¼å¯ä»¥æ¥ç®¡åºç¡ç TCP è¿æ¥å¤çç¨åºå bufio.Writer ãè¿ä½¿å¯ä»¥å¨ä¸å³é TCP è¿æ¥çæåµä¸è¯»åååå¥æ°æ®ã
// NewHandler initializes a new handler
func NewHandler(w http.ResponseWriter, req *http.Request) (*WS, error) {
hj, ok := w.(http.Hijacker)
if !ok {
// handle error
} .....
}è¦å®ææ¡æï¼æå¡å¨å¿é¡»ä½¿ç¨éå½ç头è¿è¡ååºã
// Handshake creates a handshake header
func (ws *WS) Handshake() error {
hash := func(key string) string {
h := sha1.New()
h.Write([]byte(key))
h.Write([]byte("258EAFA5-E914-47DA-95CA-C5AB0DC85B11"))
return base64.StdEncoding.EncodeToString(h.Sum(nil))
}(ws.header.Get("Sec-WebSocket-Key"))
.....
}客æ·ç«¯åèµ· WebSocket è¿æ¥è¯·æ±æ¶ç¨ç Sec-WebSocket-key æ¯éæºçæçï¼å¹¶ä¸æ¯Base64ç¼ç çãæ¥å请æ±åï¼æå¡å¨éè¦å°æ¤å¯é¥éå å°åºå®å符串ãå设ç§é¥æ¯ x3JJHMbDL1EzLkh9GBhXDw== ãå¨è¿ä¸ªä¾åä¸ï¼å¯ä»¥ä½¿ç¨ SHA-1 计ç®äºè¿å¶å¼ï¼å¹¶ä½¿ç¨ Base64 对å¶è¿è¡ç¼ç ãå¾å° HSmrc0sMlYUkAGmm5OPpG2HaGWk= ãç¶å使ç¨å®ä½ä¸º Sec-WebSocket-Accept ååºå¤´çå¼ã
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// Recv receives data and returns a Frame
func (ws *WS) Recv() (frame Frame, _ error) {
frame = Frame{}
head, err := ws.read(2)
if err != nil {
// handle error
}åè¿æ¥ï¼è¿äºä»£ç è¡å许对æ°æ®è¿è¡ç¼ç ï¼
// Send sends a Frame
func (ws *WS) Send(fr Frame) error {
// make a slice of bytes of length 2
data := make([]byte, 2)
// Save fragmentation & opcode information in the first byte
data[0] = 0x80 | fr.Opcode
if fr.IsFragment {
data[0] &= 0x7F
}
.....å³éæ¡æ
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// Close sends a close frame and closes the TCP connection
func (ws *Ws) Close() error {
f := Frame{}
f.Opcode = 8
f.Length = 2
f.Payload = make([]byte, 2)
binary.BigEndian.PutUint16(f.Payload, ws.status)
if err := ws.Send(f); err != nil {
return err
}
return ws.conn.Close()
}使ç¨ç¬¬ä¸æ¹åºå¿«éæ建WebSocketæå¡
éè¿ä¸é¢çç« èå¯ä»¥çå°ç¨ Go èªå¸¦ç net/http åºå®ç° WebSocket æå¡è¿æ¯å¤ªå¤æäºã好å¨æå¾å¤å¯¹ WebSocket æ¯æè¯å¥½ç第ä¸æ¹åºï¼è½åå°æ们å¾å¤åºå±çç¼ç å·¥ä½ãè¿éæä»¬ä½¿ç¨ gorilla web toolkit 家æçå¦å¤ä¸ä¸ªåº gorilla/websocket æ¥å®ç°æ们ç WebSocket æå¡ï¼æ建ä¸ä¸ªç®åç Echo æå¡ï¼ Echo æææ¯åé³ï¼å°±æ¯å®¢æ·ç«¯åä»ä¹ï¼æå¡ç«¯åææ¶æ¯ååç»å®¢æ·ç«¯ï¼ã
æä»¬å¨ http_demo 项ç®ç handler ç®å½ä¸æ°å»ºä¸ä¸ª ws åç®å½ç¨æ¥åæ¾ WebSocket æå¡ç¸å³çè·¯ç±å¯¹åºç请æ±å¤çç¨åºã
å¢å 两个路ç±ï¼
/ws/echoEchoåºç¨çWebSocket æå¡çè·¯ç±/ws/echo_displayEchoåºç¨ç客æ·ç«¯é¡µé¢çè·¯ç±ã å建WebSocketæå¡ç«¯
// handler/ws/echo.go
package ws
import (
"fmt"
"github.com/gorilla/websocket"
"net/http"
)
var upgrader = websocket.Upgrader{
ReadBufferSize: 1024,
WriteBufferSize: 1024,
}
func EchoMessage(w http.ResponseWriter, r *http.Request) {
conn, _ := upgrader.Upgrade(w, r, nil) // å®éåºç¨æ¶è®°å¾åé误å¤ç
for {
// 读å客æ·ç«¯çæ¶æ¯
msgType, msg, err := conn.ReadMessage()
if err != nil {
return
}
// ææ¶æ¯æå°å°æ åè¾åº
fmt.Printf("%s sent: %s\n", conn.RemoteAddr(), string(msg))
// ææ¶æ¯åå客æ·ç«¯ï¼å®æåé³
if err = conn.WriteMessage(msgType, msg); err != nil {
return
}
}
}connåéçç±»åæ¯*websocket.Conn,websocket.Connç±»åç¨æ¥è¡¨ç¤ºWebSocketè¿æ¥ãæå¡å¨åºç¨ç¨åºä»HTTP请æ±å¤çç¨åºè°ç¨Upgrader.Upgradeæ¹æ³ä»¥è·å*websocket.Conn- è°ç¨è¿æ¥ç
WriteMessageåReadMessageæ¹æ³åéåæ¥æ¶æ¶æ¯ãä¸é¢çmsgæ¥æ¶å°åå¨ä¸é¢ååä¼ ç»äºå®¢æ·ç«¯ãmsgçç±»åæ¯[]byteã
å建WebSocket客æ·ç«¯
å端页é¢è·¯ç±å¯¹åºç请æ±å¤çç¨åºå¦ä¸ï¼ç´æ¥è¿å views/websockets.html ç»å°æµè§å¨æ¸²æ页é¢å³å¯ã
// handler/ws/echo_display.go
package ws
import "net/http"
func DisplayEcho(w http.ResponseWriter, r *http.Request) {
http.ServeFile(w, r, "views/websockets.html")
}websocket.html éæ们éè¦ç¨ JavaScript è¿æ¥ WebScoket æå¡è¿è¡æ¶åæ¶æ¯ï¼ç¯å¹åå æå°±åªè´´ JS 代ç äº
<form>
<input id="input" type="text" />
<button onclick="send()">Send</button>
<pre id="output"></pre>
</form>
...
<script>
var input = document.getElementById("input");
var output = document.getElementById("output");
var socket = new WebSocket("ws://localhost:8000/ws/echo");
socket.onopen = function () {
output.innerHTML += "Status: Connected\n";
};
socket.onmessage = function (e) {
output.innerHTML += "Server: " + e.data + "\n";
};
function send() {
socket.send(input.value);
input.value = "";
}
</script>
...注åè·¯ç±
æå¡ç«¯å客æ·ç«¯çç¨åºé½åå¤å¥½åï¼æ们æç§ä¹å约å®å¥½çè·¯å¾ä¸ºä»ä»¬æ³¨åè·¯ç±å对åºç请æ±å¤çç¨åºï¼
// router/router.go
func RegisterRoutes(r *mux.Router) {
...
wsRouter := r.PathPrefix("/ws").Subrouter()
wsRouter.HandleFunc("/echo", ws.EchoMessage)
wsRouter.HandleFunc("/echo_display", ws.DisplayEcho)
}æµè¯éªè¯
éå¯æå¡åè®¿é® http://localhost:8000/ws/echo_display ï¼å¨è¾å¥æ¡ä¸è¾å¥ä»»ä½æ¶æ¯é½è½å次åæ¾å°æµè§å¨ä¸ã
æå¡ç«¯åæ¯ææ¶å°çæ¶æ¯æå°å°ç»ç«¯ä¸ç¶åæè°ç¨ WriteMessage ææ¶æ¯ååä¼ ç»å®¢æ·ç«¯ï¼å¯ä»¥å¨ç»ç«¯ä¸æ¥çå°è®°å½ã
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åèé¾æ¥ï¼
https://yalantis.com/blog/how-to-build-websockets-in-go/
https://www.gorillatoolkit.org/pkg/websocket
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