+++ title = “WebSocket Recipe” description = “WebSocket recipe / example for Echo” url=”/cookbook/websocket” [menu.side] name = “WebSocket” parent = “cookbook” weight = 10 +++

WebSocket

使用 net 库的 WebSocket

服务端

server.go

  1. package main
  3. import (
  4.     "fmt"
  5.     "log"
  7.     "github.com/labstack/echo"
  8.     "github.com/labstack/echo/middleware"
  9.     "golang.org/x/net/websocket"
  10. )
  12. func hello(c echo.Context) error {
  13.     websocket.Handler(func(ws *websocket.Conn) {
  14.         defer ws.Close()
  15.         for {
  16.             // Write
  17.             err := websocket.Message.Send(ws, "Hello, Client!")
  18.             if err != nil {
  19.                 log.Fatal(err)
  20.             }
  22.             // Read
  23.             msg := ""
  24.             err = websocket.Message.Receive(ws, &msg)
  25.             if err != nil {
  26.                 log.Fatal(err)
  27.             }
  28.             fmt.Printf("%s\n", msg)
  29.         }
  30.     }).ServeHTTP(c.Response(), c.Request())
  31.     return nil
  32. }
  34. func main() {
  35.     e := echo.New()
  36.     e.Use(middleware.Logger())
  37.     e.Use(middleware.Recover())
  38.     e.Static("/", "../public")
  39.     e.GET("/ws", hello)
  40.     e.Logger.Fatal(e.Start(":1323"))
  41. }

使用 gorilla 的 WebSocket

服务端

server.go

  1. package main
  3. import (
  4.     "fmt"
  5.     "log"
  7.     "github.com/labstack/echo"
  9.     "github.com/gorilla/websocket"
  10.     "github.com/labstack/echo/middleware"
  11. )
  13. var (
  14.     upgrader = websocket.Upgrader{}
  15. )
  17. func hello(c echo.Context) error {
  18.     ws, err := upgrader.Upgrade(c.Response(), c.Request(), nil)
  19.     if err != nil {
  20.         return err
  21.     }
  22.     defer ws.Close()
  24.     for {
  25.         // Write
  26.         err := ws.WriteMessage(websocket.TextMessage, []byte("Hello, Client!"))
  27.         if err != nil {
  28.             log.Fatal(err)
  29.         }
  31.         // Read
  32.         _, msg, err := ws.ReadMessage()
  33.         if err != nil {
  34.             log.Fatal(err)
  35.         }
  36.         fmt.Printf("%s\n", msg)
  37.     }
  38. }
  40. func main() {
  41.     e := echo.New()
  42.     e.Use(middleware.Logger())
  43.     e.Use(middleware.Recover())
  44.     e.Static("/", "../public")
  45.     e.GET("/ws", hello)
  46.     e.Logger.Fatal(e.Start(":1323"))
  47. }

客户端

index.html

  1. <!doctype html>
  2. <html lang="en">
  4. <head>
  5.   <meta charset="utf-8">
  6.   <title>WebSocket</title>
  7. </head>
  9. <body>
  10.   <p id="output"></p>
  12.   <script>
  13.     var loc = window.location;
  14.     var uri = 'ws:';
  16.     if (loc.protocol === 'https:') {
  17.       uri = 'wss:';
  18.     }
  19.     uri += '//' + loc.host;
  20.     uri += loc.pathname + 'ws';
  22.     ws = new WebSocket(uri)
  24.     ws.onopen = function() {
  25.       console.log('Connected')
  26.     }
  28.     ws.onmessage = function(evt) {
  29.       var out = document.getElementById('output');
  30.       out.innerHTML += evt.data + '<br>';
  31.     }
  33.     setInterval(function() {
  34.       ws.send('Hello, Server!');
  35.     }, 1000);
  36.   </script>
  37. </body>
  39. </html>

输出示例

Client

  1. Hello, Client!
  2. Hello, Client!
  3. Hello, Client!
  4. Hello, Client!
  5. Hello, Client!

Server

  1. Hello, Server!
  2. Hello, Server!
  3. Hello, Server!
  4. Hello, Server!
  5. Hello, Server!