如何使用Go语言构建WebSocket服务器

go get github.com/gorilla/websocket

package main

import (
    "log"
    "net/http"
    "github.com/gorilla/websocket"
)

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

func main() {
    http.HandleFunc("/echo", echoHandler)
    log.Fatal(http.ListenAndServe(":8080", nil))
}

func echoHandler(w http.ResponseWriter, r *http.Request) {
    conn, err := upgrader.Upgrade(w, r, nil)
    if err != nil {
        log.Println(err)
        return
    }
    defer conn.Close()

    for {
        messageType, message, err := conn.ReadMessage()
        if err != nil {
            log.Println(err)
            break
        }
        log.Printf("Received message: %s
", message)
        err = conn.WriteMessage(messageType, message)
        if err != nil {
            log.Println(err)
            break
        }
    }
}

go run main.go

2021/08/11 15:32:31 Listening on port 8080...

var ws = new WebSocket("ws://localhost:8080/echo");
ws.onopen = function() {
    console.log("Connected");
    ws.send("Hello, World!");
};
ws.onmessage = function(event) {
    console.log("Received message: " + event.data);
};
ws.onclose = function() {
    console.log("Disconnected");
};

Connected
Received message: Hello, World!
Disconnected