1、服务端

package main

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

var UP = websocket.Upgrader{}

var conns []*websocket.Conn
var msg = make(chan string, 20)

func hanlder(w http.ResponseWriter, r *http.Request) {
    conn, err := UP.Upgrade(w, r, nil)
    if err != nil {
        log.Println(err)
        return
    }
    // 保存所有的链接
    msg <- "有人上线：" + fmt.Sprintf("%v", conn.RemoteAddr())
    go broadcast(conns)
    conns = append(conns, conn)
    for {
        _, p, e := conn.ReadMessage()
        if e != nil {
            break
        }
        // 遍历链接，广播发送消息
        msg <- fmt.Sprintf("%v：%s", conn.RemoteAddr(), string(p))
        go broadcast(conns)
    }
    conn.WriteControl(websocket.CloseMessage, []byte("关闭链接"), time.Now().Add(time.Second))
    defer conn.Close()
    log.Println("服务关闭")
}

//广播消息
func broadcast(conns []*websocket.Conn) {
    m := <-msg
    for i := range conns {
        conns[i].WriteMessage(websocket.TextMessage, []byte(m))
    }
}

func main() {
    // websocket接口
    http.HandleFunc("/", hanlder)
    // 通过web接口推送消息
    http.HandleFunc("/msg", func(writer http.ResponseWriter, request *http.Request) {
        // 从body获取消息推送
        //body := request.Body
        //b, _ := io.ReadAll(body)
        //body.Close()
        //fmt.Println(string(b))
        // 从form表单获取消息推送
        b := request.FormValue("msg")
        fmt.Println(b)
        msg <- b
        fmt.Println(conns)
        go broadcast(conns)
        writer.Write([]byte(fmt.Sprintf("%v", "发送成功")))
    })
    http.ListenAndServe(":8000", nil)
}

2、客户端

package main

import (
    "bufio"
    "fmt"
    "github.com/gorilla/websocket"
    "log"
    "os"
)

func main() {
    dl := websocket.Dialer{}
    conn, _, err := dl.Dial("ws://127.0.0.1:8000", nil)
    if err != nil {
        log.Println(err)
        return
    }
    go send(conn)
    for {
        m, p, e := conn.ReadMessage()
        if e != nil {
            break
        }
        fmt.Println(m, string(p))
    }
    defer conn.Close()
}

func send(conn *websocket.Conn) {
    for {
        reader := bufio.NewReader(os.Stdin)
        l, _, _ := reader.ReadLine()
        conn.WriteMessage(websocket.TextMessage, l)
    }
}