Golang WebSocket 프로그래밍 가이드: 고성능 실시간 애플리케이션 구축

package main

import (
    "log"
    "net/http"

    "github.com/gorilla/websocket"
)

var upgrader = websocket.Upgrader{
    CheckOrigin: func(r *http.Request) bool {
        return true
    },
}

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.Fatal("upgrade error:", err)
    }
    defer conn.Close()

    for {
        messageType, message, err := conn.ReadMessage()
        if err != nil {
            log.Println("read error:", err)
            break
        }
        log.Println("receive:", string(message))

        err = conn.WriteMessage(messageType, message)
        if err != nil {
            log.Println("write error:", err)
            break
        }
    }
}

package main

import (
    "log"
    "net/http"

    "github.com/gorilla/websocket"
)

var upgrader = websocket.Upgrader{
    CheckOrigin: func(r *http.Request) bool {
        return true
    },
}

type Message struct {
    Username string `json:"username"`
    Content  string `json:"content"`
}

type Room struct {
    clients  map[*websocket.Conn]bool
    broadcast chan Message
    join     chan *websocket.Conn
    leave    chan *websocket.Conn
}

func (r *Room) start() {
    for {
        select {
        case conn := <-r.join:
            r.clients[conn] = true
        case conn := <-r.leave:
            delete(r.clients, conn)
            close(conn)
        case message := <-r.broadcast:
            for conn := range r.clients {
                err := conn.WriteJSON(message)
                if err != nil {
                    log.Println("write error:", err)
                    delete(r.clients, conn)
                    close(conn)
                }
            }
        }
    }
}

func main() {
    r := Room{
        clients:  make(map[*websocket.Conn]bool),
        broadcast: make(chan Message),
        join:     make(chan *websocket.Conn),
        leave:    make(chan *websocket.Conn),
    }

    go r.start()

    http.HandleFunc("/ws", func(w http.ResponseWriter, r *http.Request) {
        conn, err := upgrader.Upgrade(w, r, nil)
        if err != nil {
            log.Fatal("upgrade error:", err)
        }

        r.join <- conn

        defer func() {
            r.leave <- conn
        }()

        for {
            var message Message
            err = conn.ReadJSON(&message)
            if err != nil {
                log.Println("read error:", err)
                break
            }

            r.broadcast <- message
        }
    })

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