How to Implement WebSockets in Go with gorilla/websocket

Use the gorilla/websocket library to upgrade HTTP connections to WebSockets and handle bidirectional messaging.

package main

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

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

func handler(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 {
            break
        }
        err = conn.WriteMessage(messageType, message)
        if err != nil {
            break
        }
    }
}

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

WebSockets allow your server and client to talk to each other instantly without waiting for a request. Think of it like a two-way walkie-talkie instead of sending letters back and forth. You use this when you need real-time updates, like in chat apps or live dashboards.