Go网络编程-Websockets

这个例子将展示如何在Go中使用websockets。我们将构建一个简单的服务器，它将回显我们发送给它的所有内容。为此，我们必须像这样获取流行的gorilla/websocket库：

$ go get github.com/gorilla/websocket

从现在开始，我们编写的每个应用程序都将能够使用这个库。

// websockets.go
package main

import (
    "fmt"
    "net/http"

    "github.com/gorilla/websocket"
)

var upgrader = websocket.Upgrader{
    ReadBufferSize:  1024,
    WriteBufferSize: 1024,
}

func main() {
    http.HandleFunc("/echo", func(w http.ResponseWriter, r *http.Request) {
        conn, _ := upgrader.Upgrade(w, r, nil) // error ignored for sake of simplicity

        for {
            // Read message from browser
            msgType, msg, err := conn.ReadMessage()
            if err != nil {
                return
            }

            // Print the message to the console
            fmt.Printf("%s sent: %s\n", conn.RemoteAddr(), string(msg))

            // Write message back to browser
            if err = conn.WriteMessage(msgType, msg); err != nil {
                return
            }
        }
    })

    http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
        http.ServeFile(w, r, "websockets.html")
    })

    http.ListenAndServe(":8080", nil)
}

<!-- websockets.html -->
<input id="input" type="text" />
<button onclick="send()">Send</button>
<pre id="output"></pre>
<script>
    var input = document.getElementById("input");
    var output = document.getElementById("output");
    var socket = new WebSocket("ws://localhost:8080/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>

$ go run websockets.go
[127.0.0.1]:53403 sent: Hello Go Web Examples, you're doing great!