Question

我一直在尝试使用Golang中的websockets在服务器端推送更改。

我已经通过此代码获得了我想要的东西

服务器端代码：

package main

import (
   "golang.org/x/net/websocket"
   "fmt"
   "net/http"
   "os"
   "bufio"
)

type chat struct {
    message string
}

func (ms *chat) Echo(ws *websocket.Conn) {
    var reply string
    for {
         if reply !=  ms.message {
         websocket.Message.Send(ws, ms.message)
         }
         websocket.Message.Receive(ws, reply)
    }
}

func NewMessage(s *string){
   reader := bufio.NewReader(os.Stdin)
   for {
       fmt.Print("Enter text: ")
       *s, _ = reader.ReadString('\n')
       }
   }

func main() {
   myString := chat{"Welcome"}
   go NewMessage(&myString.message)
   http.Handle("/", websocket.Handler(myString.Echo))
   http.ListenAndServe(":1234", nil)
}

客户端代码：

<html>
<body>
<script type="text/javascript">
    var exampleSocket = new WebSocket("ws://127.0.0.1:1234");

    exampleSocket.onopen = function (event) {
    console.log("connected");
    };

    exampleSocket.onmessage = function (event) {
        console.log(event.data);
        exampleSocket.send(event.data)
        document.getElementById("p1").innerHTML = event.data;
    }


</script>
<h1>WebSockets</h1>
<form>
    <p id="p1" value="Hello, world!"/>
</form>

以上代码的问题是重复发送ms.message，因为if reply != ms.message不起作用。 var reply string只是websocket.Message.Receive(ws, reply)值不会改变reply值。

我尝试将package main import ( "golang.org/x/net/websocket" "fmt" "net/http" "os" "bufio" ) type chat struct { message string } func (ms *chat) Echo(ws *websocket.Conn) { var reply string for { if reply != ms.message { websocket.Message.Send(ws, ms.message) } websocket.Message.Receive(ws, &reply) } } func NewMessage(s *string){ reader := bufio.NewReader(os.Stdin) for { fmt.Print("Enter text: ") *s, _ = reader.ReadString('\n') } } func main() { myString := chat{"Welcome"} go NewMessage(&myString.message) http.Handle("/", websocket.Handler(myString.Echo)) http.ListenAndServe(":1234", nil) }作为指针传递，但它不会动态更新客户端的值。

以下是更改后服务器端的外观：

selected

此代码不符合我的期望。

是否可以在客户端动态更新字符串而不像在示例1中那样多次发送值？

Answer 1

只需将websocket.Message.Receive放入if语句即可解决问题。

package main

import (
   "golang.org/x/net/websocket"
   "fmt"
   "net/http"
   "os"
   "bufio"
)

type chat struct {
   message string
}

func (ms *chat) Echo(ws *websocket.Conn) {
   var reply string
      for {
         if reply !=  ms.message {
            websocket.Message.Send(ws, ms.message)
            websocket.Message.Receive(ws, &reply)
         }

      }
}

func NewMessage(s *string){
reader := bufio.NewReader(os.Stdin)
for {
   fmt.Print("Enter text: ")
   *s, _ = reader.ReadString('\n')
  }
}

func main() {
   myString := chat{"Welcome"}
   go NewMessage(&myString.message)
   http.Handle("/", websocket.Handler(myString.Echo))
   http.ListenAndServe(":1234", nil)
}

使用websockets Golang将更改推送到客户端

1 个答案: