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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// 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
   }
  â¦

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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
  }     .....
}

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// 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"))
  .....
}

å®¢æ·ç«¯åèµ· WebSocket è¿æ¥è¯·æ±æ¶ç¨ç Sec-WebSocket-key æ¯éæºçæçï¼å¹¶ä¸æ¯Base64ç¼ç çãæ¥åè¯·æ±åï¼æå¡å¨éè¦å°æ¤å¯é¥éå å°åºå®åç¬¦ä¸²ãåè®¾ç§é¥æ¯ x3JJHMbDL1EzLkh9GBhXDw== ãå¨è¿ä¸ªä¾åä¸ï¼å¯ä»¥ä½¿ç¨ SHA-1 è®¡ç®äºè¿å¶å¼ï¼å¹¶ä½¿ç¨ Base64 å¯¹å¶è¿è¡ç¼ç ãå¾å° HSmrc0sMlYUkAGmm5OPpG2HaGWk= ãç¶åä½¿ç¨å®ä½ä¸º Sec-WebSocket-Accept ååºå¤´çå¼ã

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使用Go语言创建WebSocket服务的实现示例

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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
  }

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// 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
  }
  .....

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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()
}

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éè¿ä¸é¢çç« èå¯ä»¥çå°ç¨ Go èªå¸¦ç net/http åºå®ç° WebSocket æå¡è¿æ¯å¤ªå¤æäºãå¥½å¨æå¾å¤å¯¹ WebSocket æ¯æè¯å¥½çç¬¬ä¸æ¹åºï¼è½åå°æä»¬å¾å¤åºå±çç¼ç å·¥ä½ãè¿éæä»¬ä½¿ç¨ gorilla web toolkit å®¶æçå¦å¤ä¸ä¸ªåº gorilla/websocket æ¥å®ç°æä»¬ç WebSocket æå¡ï¼æå»ºä¸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 é¡¹ç®ç handler ç®å½ä¸æ°å»ºä¸ä¸ª ws åç®å½ç¨æ¥åæ¾ WebSocket æå¡ç¸å³çè·¯ç±å¯¹åºçè¯·æ±å¤çç¨åºã

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/ws/echo Echo åºç¨çWebSocket æå¡çè·¯ç±
/ws/echo_display Echo åºç¨çå®¢æ·ç«¯é¡µé¢çè·¯ç±ã åå»ºWebSocketæå¡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®°å¾åéè¯¯å¤ç

	for {
		// è¯»åå®¢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¯ååå®¢æ·ç«¯ï¼å®æåé³
		if err = conn.WriteMessage(msgType, msg); err != nil {
			return
		}
	}
}

conn åéçç±»åæ¯ *websocket.Conn , websocket.Conn ç±»åç¨æ¥è¡¨ç¤º WebSocket è¿æ¥ãæå¡å¨åºç¨ç¨åºä» HTTP è¯·æ±å¤çç¨åºè°ç¨ Upgrader.Upgrade æ¹æ³ä»¥è·å *websocket.Conn
è°ç¨è¿æ¥ç WriteMessage å ReadMessage æ¹æ³åéåæ¥æ¶æ¶æ¯ãä¸é¢ç msg æ¥æ¶å°åå¨ä¸é¢ååä¼ ç»äºå®¢æ·ç«¯ã msg çç±»åæ¯ []byte ã

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// 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 éæä»¬éè¦ç¨ JavaScript è¿æ¥ WebScoket æå¡è¿è¡æ¶åæ¶æ¯ï¼ç¯å¹åå æå°±åªè´´ JS ä»£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>
...

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// router/router.go
func RegisterRoutes(r *mux.Router) {
 ...
 wsRouter := r.PathPrefix("/ws").Subrouter()
 wsRouter.HandleFunc("/echo", ws.EchoMessage)
 wsRouter.HandleFunc("/echo_display", ws.DisplayEcho)
}

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使用Go语言创建WebSocket服务的实现示例

使用Go语言创建WebSocket服务的实现示例 æ»ç»

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https://yalantis.com/blog/how-to-build-websockets-in-go/

https://www.gorillatoolkit.org/pkg/websocket

使用Go语言创建WebSocket服务的实现示例

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